Synthetic motor oil

pulgo · April 2001

I just read on German website that the oil change interval for the Toyota Yaris (our Echo) with the 1.5 Liter engine is every 15000 Kms (9300 miles) or once a year. This is with synthetic oils of course and they recommend 5W40, 0W30 and similars.

How come this is the recommendation considering the fact that they typically drive at higher speeds (Autobahn), rev their engines higher and most of their trips are short? What does this say about the quality of engine oils sold in North America?

armtdm · April 2001

It has to do with oil company and auto dealer service dept and quick lube profits. The marketing hype of these companies like Quaker State/Pennzoil and Jiffy Lube have convinced the American car owner that the oil should be changed every 3000 miles or the engine will fail or warranty not be honored. It is as simple as that!

Consumer Reports consistently states that petroleum based oil can now go at least 5,000 miles between changes but it seems very few believe it. They prefer to keep believing an oil change is cheap insurance for a car so why not change every 3000. Don't seem to care that the oil and filter are also cheap and it may be part of the reason they recommend every 3000 miles.

armtdm · April 2001

For informational purposes I was informed that Amsoil now offers the 5W20 full synthetic oil. However, it is the XL 7500 series which means that they recommend changing it at 6 months or 7,500 miles. It is not their series of oil which they recommend 25,000-35,000.

They say it offers superior protection over the petroleum oils out there but obviously the 5W20 weight has them lowering their change intervals to the 7500. Their XL7500 series does not have the same additive package for longer usage and is intended more for the quick lube business.

Happy that I do not have to use 5W20 as yet!

riswami · April 2001

What is the word on Exxon Synthetic? Is it high quality when compared to Mobil 1?

adc100 · April 2001

more 20 wt. oil around. It is the best of all worlds for the auto companies. Better gas milage, shorter (yet acceptable) engine life, and probably a reason for not lengthening the interval between oil changes. Life is good (for the oil companies, Jiffy Lube and car manufactures) Just think if everyone used syn they could downgrade the durability of the engine still further, knowing that the syn could still give acceptable performance.

mdecamps · April 2001

Do you have the address to the website about the Toyota Echos in Germany? No problem if it's in German.....I speak German. I'm curious to read about what the Europeans are saying...they've been proponents of extended drain intervals for some time now.

Mark

pepper32 · April 2001

Where I work we have a Liebherr excavator and the service manual recommends oil changes at 500 hrs. Our Caterpillar books sat 250 hrs. The selling dealer says that because oil is higher priced in Germany Liebherr goes with the 500 hr. change. We change at 250 same as the Cats.

currey · May 2001

Actually, they did not lower the mileage limit on the XL7500 for the 5W-20, it is the same mileage limit as there XL7500 5W-30. armtdm is right though, it is in the additives that the difference is made between Amsoil's regular synthetic (25,000 miles) and their XL7500 (7500 miles). Talking with an Amsoil tech, he told me that the XL7500 line was created for the jiffy lube business. They figured people (and lube shops) who wanted a synthetic would be willing to go 7500 miles or six months, however, as these shops are used for the average Joe (oil change must be 3000 miles), they would have a hard time convincing them to go longer than 7500 miles even if the rest of the automotive world new the synthetic oil could do it. Thus, the XL7500 line does not have the additives in it to go for the longer haul.

Again, I am soooooo happy somebody has a synthetic 5W-20, BUT, once I am through my warranty period I will be using synthetic 5W-30.

pulgo · May 2001

Here's one of the websites I mentioned:

http://www.lesezeichenverlag.de/versand/yaris.htm

(The Echo is called YARIS in Europe)

pulgo · May 2001

This is the other website:

http://www.carija.de/pdf/Yaris_Datenblatt_032000.pdf (in German)

jimmah · May 2001

I have a 2000 Toyota Echo. I switched to Amsoil 0W-30 and installed a bypass oil filter. My gas mileage increased about 2 mpg, getting 37-39 mpg driving in Atlanta roads without the AC. I could also feel a smoother engine and faster acceleration, not much but noticeable. The bypass filter keeps the oil cleaner much longer. I plan on changing the oil at 20,000 miles intervals and the bypass filter, which is 8 inches tall x 4 inches in diameter, every 40,000 miles. Regular oil filter (Amsoil) every 10,000 miles. I also plan to sample the oil for analysis about every other year. First sample with 10740 miles was still acceptable. I have run synthetic oils for the past 25 years and believe in extended oil changes and no problems. I typically run my vehicles until about 125,000-150,000 miles before I get tired of that style, which is about 8-9 years for me. You can call Amsoil number 800-956-5695 and use my customer id number 402023. Enjoy the performance of synthetic oils, which is a much higher quality product than petroleum oil. Synthetic oils are man-made so they are technical engineered products, hence the higher cost. You are better off in the long run with synthetics, even overall cost savings with improved gas mileage and less oil changes. My profession, mechanical engineer at a power plant.

bluedevils · May 2001

At 5,200 miles on current oil, I'm ready for a change on my 95 Contour's Mobil1 5W-30. I have several quarts of petrol-based ("dino") oil laying around. I'm wondering if it would do my engine any good to pour in this new oil and drain it right away (probably just leaving the drain plug out)?

I have no reason to believe that my engine is excessively dirty-- just trying to figure out what to do with this extra dino oil.

pulgo · May 2001

jimmah:
Do you have any photos of the installation of Amsoil by-pass filters on your Echo?
What was the total cost and where exactly did you install it?
Which one of the by-pass filters do you use?
Any info you provide will be helpful as I intend to install this system my self.
One exception, though: I will not use Amsoil oil because I believe it is too expensive and it's easier for me to obtain Mobil 1 locally.

haspelbein · May 2001

Okay, it's been a while since I lived in Germany, but it is actually hard to get anything but synthetic oil over there. Some large outlets sell mineral oil, but the default is always synthetic oil. 15000 km sounds about right, and also matches the interval that I've found in the German enthusiast's handbook for my Benz. (But that engine also holds more oil than the average US car I've owned.)

One more thing to consider: The recycling fees for used oil are higher in Germany.

pulgo · May 2001

You are right. Dino oil starts at about DM 8 (US$3.60 aprox) and syn oil can easily cost US$ 10 per liter and more. A very good incentive to use the oil for as long as possible.
*herzlichen Gruss aus Vancouver*

dpwestlake · May 2001

Drian the old oil, put in the fresh mineral oil and drive around for a while (10-20 mi) until the oil heats up then carefully drain and fill with synthetic. Change the filter when you put in the synthetic.

If you really want to clean it get a can of engine flush. Follow the instructions on the can.

steverisity · May 2001

It has been one year since I purchased my Y2K Z3 BMW which came with synthetic oil and 36 months of maintenance included. I called my local dealer for my one year check up and after telling him I have 7,000 miles on the car, he said my first check up and oil change is at 15k miles!

Could this be right, to go 2 years or 15k miles before my first oil change?
He said if I want it done earlier it would be on my on nickle.

I'm wondering if BMW didn't recommend an oil change at 7k miles when they didn't include service with the cost of the car.

haspelbein · May 2001

Steversity...what does the service indicator say ? I have a '97 Z3 which I bought in February. I was planning on waiting for the service indicator to signal an oil change. I might also change the oil after 6 months, mainly because the car doesn't get driven all that much and I want to avoid oil contamination through condensation.

I'd simply do the oil change myself if it makes you feel better. I personally wouldn't be too concerned with the 15000 miles, but rather with going for two years without changing the oil.

steverisity · May 2001

Did your Z come with Maintenance included?
What does your manual recommend?

My indicator has not gone on yet. But I'm assuming it's not very intelligent
and simply goes on at a certain odometer reading as opposed to sensing
oil contamination or degredation.

I will likely change the oil on my own. It just doesn't seem right to me to say that all scheduled maintenance is included and then all of a sudden change the rules to 15k miles being the first oil change. If BMW is not consistant, then they're either short changing owners now or were ripping people off in the past.

armtdm · May 2001

The engine must be very small for a bypass to fit in there, most new cars simply do not have the room for a bypass. Also, with the bypass Amsoil claims unlimited oil life yet you are changing at 20,000 miles. Why bother with the bypass???????

mdecamps · May 2001

I was in Germany a couple of years ago and got into a heated discussion with a German about oil change intervals. Keep in mind that this was before I was "converted" to synthetic oil. The German argued that there was no reason to change oil any sooner than 15,000km or 10,000mi. I was stuck in my 3,000mi routine and argued my point. I can remember thinking what the inside of his engine looked like. Looking back, I'm sure that his engine was spotless with a good grade of synthetic. Our 2001 Volkswagen Jetta came out of the factory with Castrol (YUK) Syntek and requires 10K oil changes under all driving conditions....I think the Germans are onto something.....

Danke Pulgo fuer alles was Sie geschrieben haben!

Mark

armtdm · May 2001

Only problem I have with your post is that Castrol Syntec is not a synthetic oil, just a product of misleading and false advertising using a regurgetated petroleum product and reaping in huge profits by selling it as a synthetic!!!!!

div2 · May 2001

The BMW SI indicator originally calculated service intervals based on engine ram, engine temperature, and other factors. Munch's engineers discovered that fuel consumption alone was equally accurate. Reason? High fuel consumption is indicative of hard driving, short trips and stop and go traffic, while low fuel consumption reflect less severe "highway miles". In any event, I would change oil on at least an annual basis. DO NOT reset the SI lights until they indicate an Oil Service or Inspection, otherwise you'll screw up the servicing sequence.

haspelbein · May 2001

No, mine did not come with service included, but I haven't had to bring it in for service, yet.

div2 is correct in stating that the service indicator is actually rather accurate on how hard the car is being driven.
(It's interesting to see that MB actually has a sensor that measures the dielectric constant of the oil to determine the degradation.)

The Bentley service manual for the Z states that it is expected to have an oil change intervals of > 7k miles, depending on when the service indicator demands it.
Or in short, you probably can just follow the service indicator, bring the car to the dealership, and you'll be just fine. And I can somewhat understand BMWs side when they only cover the indicated services.

However, if you want the warm, fuzzy feeling of being on the safe side, just change it earlier. (And don't reset the lights, just as div2 said.)

brucer2 · May 2001

What is "Synthetic" Motor Oil? texasoil

Here is the REAL technical information.

Mobil 1 is formulated with what are called Poly-alpha-olefins (PAO's). These molecules look like a zipper or the wire in a chain link fence, with a single unsaturated bond on the end (the 'alpha-olefin). These molecules are pretty good for use in lube oils because they hold their viscosity better with temperatures than 'conventional' lube oil molecules. They are not perfect however. they are not very good solvents for theadditives and combustion byproducts in an engine, so the detergent and dispersant additives have to be 'better' than in 'conventional' lube oils. Also, some co-solvent conventional base oil has to be included to keep the additives in solution.

A refining process developed a few years ago and first used by Shell Oil 'isomerizes' paraffin wax so that the isomerized molecules look and behave almost exactly like the PAO molecules- but without the terminal double bond.

These are very different approaches to making essentially the same 'synthetic' molecules. PAO's are made by connecting a whole bunch of ethylene molecules (the poly), while isomerization starts with natural molecule and rearranges it.

Now interestingly, petroleum waxes are often 'cracked' or split up into the samll ethylene molecules that are then polymerized back togetherinto PAO's.!!. Now which way do you think is more costly? Tearing up molecules and then glueing them back together, or rearranging ones nature has already made?

By the way, if petroleum wax, which is mostly straight chain or 'normal' paraffins did not freeze solid at such high temperatures (130F or so) it makes an outstanding lubricant base oil. 'Isomerizing' rearranges some of the 'normal' portion of the wax molecule into 'iso' paraffins-basically adding a few bends and pieces or wire to the main piece.

The Courts found that since neither of these molecules were 'natural' and both are 'synthetic', actually do look almost identical, and behave essentially the same in lube oil, that Castrol (and others) could call oils blended with either as "Synthetic."

This is a real victory for we consumer because it means that lower cost 'synthetics' are finally going to happen. These are better base oils for engines, but do cost more to make than 'conventional' ones.

vadp · May 2001

<<<This is a real victory for we consumer because it means that lower cost 'synthetics' are finally going to happen.>>>
O, yea? Does Castrol charge any less for its "synthetic"?

dpwestlake · May 2001

No, Castrol costs MORE than Mobil1. At least in my area.

piglover · May 2001

So do most agree that 5W-20 is recommended for 2001 Ford vehicles (and some posts even said Honda requires it) to increase fuel economy? Aren't the engines in the 2000 Fords and Honda the same as the 2001 or were they redesigned in some way? If a 2000 Ford or Honda used 5W-30 then it should follow that a 2001 could use it too.
I would gladly sacrifice some fuel economy for a better lubricated engine. With the hot summertime temperatures 5W-30 couldn't hurt, right?

adc100 · May 2001

the Ford engines were redesigned to utilize the 20 wt. Idon't know what year this was done. First of all I would not have purchased the vehicle because of this fact alone. As I said.. If it were mine 10W30 Mobil 1 goes in. Appropriate receits for 5W-20 would be available.

pepper32 · May 2001

The Ford engines were not reenginered for 20 wieght oil. I had the oil changed at the dealers in my '98 F150 and they used 5w20. I told the service manger about thier mistake and he pulled out a TSB stating Ford recommends 5w20 for a number of engines dating back to the early '90's. One exception is the 4.0L which did not meet engine wear standards.

vadp · May 2001

Same here. My 2000 Ford manual recommends 5W30.
During my recent free oil change the technician put 5W20 weight in my car. After questioning, the tech told me that he followed Ford's directions .

jimmah · May 2001

Pulgo, I installed the bypass filter in the space behind the left headlight. I installed the BE-100 (8") because the dealer was out of stock of the BE-90 (6"). There is enough room to install the BE-110 (10") and it is only $US 2 difference between each size. The filter adapter is bolted to a 4inch cross member, take the battery out and it is easy. The labor was about $US250 and 6 hours labor because the guy had to find adapter fittings from the oil sending unit to the Amsoil adapter, remove the valve cover, drill and tap for the return to the back side of the valve cover. Was it worth it, probably not in hind sight, but I like technical things and am willing to experiment. The oil stays cleaner about 3 times longer. I have 15,000 miles on the oil now and will sample at 20,000 miles to see if I can continue or decide to change oil. Even though some people say you could run the life of the car without changing the oil, only oil analysis will tell. I know after running 25 years on synthetic, over time, the oil is cooked and thickens to the point that gas mileage decreases. Synthetics just last longer. My initial plan was to run the oil for 2 years or 40,000 miles even though the samples were good. My experience with the oil without the bypass filter, lasted about 20-25k miles if everything else in the engine is running perfect. With oil analysis, I determined my 1992 Ford Econoline could not make it pass 8000 miles before the oil properties were out of spec. The Ford still ran fine at 124,000 miles before I sold it to by the ECHO. 37 mpg sure beats 16 mpg. I also have a Honda Odyssey but can't find a place to install the bypass filter or the dual remote. My planned oil change interval on the Honda will be 15-20K miles if the oil analysis goes the way I predict. I averaged about 24.5 mpg at 75 mph for my trip to Canada over spring break. This is about 1.5 higher than when I was on the original petroleum stuff. If you become an AMSOIL dealer, the oil doesn't cost that much more given what I perceive as benefits over Mobil 1. I used Mobil 1 and AMSOIL back in 1975, and I preferred AMSOIL. I switched to Mobil 1 back then because of cost, but hey I did not have a job then. For the extra $US8 per oil change over Mobil 1, I can afford it. I also feel comfortable being able to communicate with AMSOIL if I have technical questions. GO to AMSOIL.com Happy hunting!

dpwestlake · May 2001

It sounds like an awful hassle over 4 qts of oil. Wouldn't it just be more cost effective to change it at 5K?

pulgo · May 2001

jimmah, thank you very much for the detailed explanation. I think I will go ahead and have the Amsoil dual filter system installed pretty soon.
It is doing a great job on my '91 Caprice (210k miles) and using only about 1/2 quart every 8k miles.

dpwestlake: Cost effective? Probably not. But if cost is the only reason why don't we all commute on bikes? Wouldn't that be cheaper and more cost effective? All of us fix up our cars, some buy expensive wheels, stereo equipment, etc. Others invest a little in good oil and filters and have cars that (hopefully) last a little bit longer.

dpwestlake · May 2001

Years ago I was a truck mechanic. We had bypass filters on a lot of the trucks. but they held anywhere from 24 to 60 qts of oil. It just seems to me that it would make more sense to change the 4 quarts of oil.

For the $250 labor to install the bypass filter you could buy enough Mobil 1 to change the oil about 14 times!

pulgo · May 2001

You are absolutely right. I makes no sense financially. But isn't it fun to mess with our perfectly good cars anyway?

bonitatl · May 2001

Amsoil now has 5w-20 available. It's about $5.20/qt. www.amsoil.com

Dave

pulgomaus · May 2001

yupyupyup:

Compared to whatever vehicle(s) you drive jimmah (and I) are saving hundreds of dollars per year, probably many thousands over the life of the car.
I accept that you drive any car you choose, even if that means contributing your bigger share of pollutants to our air. That's your prerrogative. I don't think it's appopriate to belittle other people's choice of car.
I also own a Chevrolet Caprice (bought new) and a Chevrolet K1500 (2 years old), but I use my Echo to drive to work daily and, believe me, it's a fun to drive little car. Just because you choose to drive something more expensive doesn't make your choice any better or worse, it's just your personal choice.

adc100 · May 2001

You'll have to argue that with Automotive Engineering Magazine. The article was quite factual and detailed. They said Ford's engines were redesigned in part to accomodate the 20 wt oil.

jimmah...I know this is still a matter of personel preference. But you'll have to tell me what the advantages of Amsoil over Mobil 1 are. I was a dealer once and I have used both products. I believe that Mobil 1' s documented testing program is more public than Amsoil's. I also believe that Amsoil is also a fine product.

dpwestlake · May 2001

I didn't think I made any negative comments about your choice of vehicle. If you interpreted ny comments that way I apologize.

I was simply questioning why one would install an elaborate filtration system to get 40K out of 4 qts of oil, although you've most likely increased the capacity to 5+ with the big filter.

If the answer is "Just for the hell of it." that's as valid to me as any other answer. people have questioned my sanity for restoring a TR7 and a V4 Saab.

If you're interested in experimenting how long you can get oil to last why don't you also install an oil cooler? It may prevent the oil from degrading from heat.

Another question: over 40K won't you end up changing the oil by just having to add oil now and then? All engines lose a bit of oil past the rings and valve seals. Don't you anticipate adding at least 4 qts over 40K?

brorjace · May 2001

BlueDevil - I did what you're thinking of. at 100,000 miles, I have my Honda (which has used synthetic 90% of the time) a dead-dino enema using Pennzoil 10W30. I put it in along with a cheap oil filter and ran it for 20 days and then drained it and removed the filter. Wow, that stuff soaked up a lot of black stuff inside my fairly clean engine. I then add a new filter and refilled the motor with Valvoline Synpower. Never use an "engine flush," you are just asking for trouble.

Brucer2 - That is Castrol's basic response to the whole Syntec vs. Mobil 1 issue. It's not 100% BS but it IS spin. Just look at that bit about the consumer benefitting ... even though Castrol has not reduced their retail price at all!

As for European drain intervals, don't forget to factor politics into the equation. Europe imports a great deal of their petroleum and they may be encouraging people to get the most out of each quart of motor oil ... and disposal is another problem. Remember, it was the EPA that gave us 5W20 oil ...

--- Bror Jace

pulgo · May 2001

By keeping the oil in the engine as long as you suggest you would effectively have replaced (or consumed) all oil by the 40K mark. On the other hand the microfiltering with the dual Amsoil filter will add significant life (I hope) to the engine, possibly doubling it. Too bad no one has compared two identical cars, one with the by-pass filter and one without, to determine which one of the engines lasts longer and by how much.

adc100 · May 2001

I'm all for anything which will preserve engine life beyond what is expected. The presumption is that less wear will lead to better reliability. To me reliability is the key. Coupled with this low wear, syn can also help preserve the engine if bad things happen, such as a coolant leak. It gives me added confidense that the vehicle will get my wife and daughter where they need to go.

I believe the add on filters may detract from overall vehicle reliability by adding lots more pressure boundaries, fittings, hoses, etc. These things have not undergone the evaluation which the vehicle manufacturer put into each vehicle. They are somewhat of a one size fits all approach. Hoses can rub other parts, fittings can vibrate lose.

I am also dubious about your guesstimate for doubling engine life. Mobil has ran many 200,000 mile tests on many vehicles. Filters(standard-not even Pure-One calibre) are chananged at 7500 miles and oil (Mobil 1) AT 7500 OR 1500 MILES. Results are, that all wear parts come up to specs for new parts. I'm guessing the engine wears out or fails via other than oil related failures. Who knows?? Besides the super clean oil probably will not affect ring wear as there are abrasion products entering here constantly.

So for me it's a nice feel good concept that has more risks than benefits.

pulgo · May 2001

Well, you are probably right. My only experience with Amsoil filters was my previous truck, a GMC that ran 332K miles and when time came for a rebuild (so I thought) the rebuilder said that no new parts were necessary and the engine looked good for another couple hundred thousand miles.
I sold the truck so I don't know how long it lasted.

adc100 · May 2001

It's been successful for you and that's what counts. I can't really blame you for going with it. When things work for me I go back to it.

Later,
Al

mdecamps · May 2001

The European drain intervals may be influenced by the government there, but if you'll look at the German cars sold in America, you'll see that they recommend those same extended drain intervals right here in the US. They are known for making the best cars in the world. I lived a Germany for a while and they get many, many miles out of their engines there. I don't think it's politics as much as it is good oleo German engineering!

ssliberty · May 2001

Last week I received an update to my owners manual from Mercedes Benz which states that my 2000 ML320 now requires use of synthetic motor oil as part of the FSS. The recommended engine oils were specifically listed as follows:

Mobil 1 Synthetic 15W-50
Mobil 1 Synthetic 0W-40 (only available to dealers)
Valvoline Synthetic 5W-30
Castrol Syntec 5W-50
Castrol Syntec 10W40
Castrol TXT Softec Plus 5W-30
Shell Helix Ultra 5W-30
Shell Helix Ultra 5W-40

I'm a dyed-in-the-wool Mobil 1 user like most people on this board. Is MB telling me that Mobil 1 OW-30, 5W-30, 10W-30 are not as good as the other brands listed in similar weights?

I live in Southern California, do alot of stop and go driving, many short trips of less than 10 miles, drive to Mammoth Lakes (snow country) via the desert in both winter and summer.

At 1200 miles I changed the mystery factory oil with Mobil 1 5W-30 and plan to continue oil changes at half the FSS schedule (approx. 5000 mile intervals). I can't get a straight answer from any of the half dozen dealers in my area on what oil weight would be appropriate. What Mobil 1 weight oil would be best?

I don't like second guessing MB, but 15W-50 seems to heavy and does not provide enough cold temp. protection, and 0W-40 is not available for do-it-your-selfers. Is 5W-30 or 10W-30 Mobil 1 a reasonable alternative? What's a guy to do?

Thanks in advance!

div2 · May 2001

I live in KY and see often winter temps below 0F. I've run 15W-50 Mobil 1 year round in my BMWs since 1990 with no problems. The BMW viscosity chart indicates that non-synthetic 15W-50 is good down to 15F. FWIW, Mobil's product data sheet for 15W-50 states that 15W-50 is an acceptable substitute for 15W-40. I'd go with the 15W-50.

adc100 · May 2001

There seem to be some insonsistencies with their recommendations. The first numbers (ambient temp) range from 0 to 15. the second (hot) from 30 to 50. I'm with you - I don't like to second guess the factory engineers. However you have to remember they try to make their product bullet proof for the Joe Six-Packs of the world. If this wer my car- easy to say.

I would:

1. Call up Mercedes and get hold of their technical engineering department. It can be done if you are persistent. I would not necessarily do this step first. Find out why they are doing this- There's something fishy here.

2. Call up Mobil 1-800-ask-mobil. If you are not happy with the answer, ask the phone guy to transfer to Mobil technical engineering/research. I have done this.

3. In the meantime, if you have to change, I would go with the 10W-30(gives a bit more protection for the short trips/frequent starts.)

4. I wouldn't worry about the 5000 miles. Oil change interval doesn't appear to be the issue here. But if you do a lot of short drips, that's no big deal. You can also probably afford it. As i have said before when I was a working stiff, I learned a fair amount about oils. Syns can generally give adequate service one grade below(lower viscosity) recommended, both in the ISO (International Standards) grades and API/SAE grades.

5. Just another thought. I'm planning to go with Red Line 10W-30 on my next change. It's salty but then again-so are cars.

http://www.redlineoil.com/products.htm

Finally- The update by Mercedes is troubling- These things are sometimes done because of some unexpected condition they discovered. Keep this in mind for the future - you may have a legal case if the vehicle has oil related difficulties even after warranty. For warranty purposes and because of my last statement, I would have "proof" that I complied with their recommendations- if you get my drift.

Let me know via this board or email me on what you found. I'm curious.

Later,

Al

blujeep · May 2001

'99 Grand Cherokee. I've got 25k miles on it & I'm a little concerned after reading some of the posts here. Is it too late now to switch to syn oil?
I want to use Amsoil - they also make an engine flush product - should I first flush the engine & then add the syn oil? If I do, how long should I go b4 the first change? Should I go the full 7,500 miles or do it sooner since it's the 1st time I'm using it after 25k miles of regular oil?
Any ideas or advice??
Thanks in advance.
:-)

Synthetic motor oil

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