Engine Oil - A slippery subject Part 2

bluedevils

Truthfully, I'm not planning on going as far as repairs to valve seals/pistons/rings. The vehicle seems to run fine, and fuel consumption has not changed significantly. I'm convinced the motor is basically sound. Plus I don't feel like spending the $$$ on such work. Plus I know many folks who seem to live with high consumption rates on these motors. I do plan to change plugs soon and some other typical mileage-related maintenance items.

By the way, this is an Isuzu-made 3.5L V6. DOHC, 24 valves. I'm not sure of the other technical highlights that might be of interest to you.

adc100

I don't know if that engine has a distributor, and wires. But if it does you should replace cap/rotor/wires and then plugs. Don't ever replace plugs without checking all the stuff upstream. Wouldn't hurt to do a compression or put an OBD II Scanner on things. If you live anywhere near Harrisburg-let me know-I have one. I get down near Duke once and a while.

Other thought is to go with a 40 wt. oil. You would have to go with synthetic here. Mobil 1 0W-40, Delvac 1 5W-40, or even Rotella 5W-40, Amsoil/Redline/Shaeffers also works. An alternative which has reduced oil use in a 94 Toyota is 3 quarts of Mobil 1 10W-30 and a quart of 15W-50. I just dumped Rotella 5W-40 in it yesterday-we'll see.

Al

bluedevils

"Don't ever replace plugs without checking all the stuff upstream."

This is the kind of advice that people like me - well-meaning do-it-yourselfers who understand very little about how automobiles work - need.

I'll have to ask the Trooper folks to find out if the 3.5L on the 98 Troopers has cap/rotors/wires. IIRC, the motor is a little unusual - I think it has a coil pack directly on each plug and therefore no traditional 'spark plug wires.' Or something like that.

fleetwoodsimca

My statement in #2022 was left vague, and really on purpose. Top and bottom ends of motors is a set of terms that neglect to define the middle of the engine. If you really get down to forcing the issue of defining it all, and if the rules said there can be no third area defined as the middle, then: The dividing line must surely be the head gasket. What do you think? As far as I know, this gritty question is answerable only as a matter of opinion. (:oÞ

bluedevils

fleetwood, you don't wanna know what I think, because I have no idea. I don't even understand the basic function of 99% of the parts in an engine. E.g. what is the function of a head gasket? I have no idea. Don't know what it looks like, don't know where it's typically located, don't know what parts it interacts with, etc.

About the only thing I know is the location of the engine oil drain plug, filler cap, and oil filter.

bluedevils

My 98 Trooper is consuming a lot of oil - up to a qt. every 1200-1500 miles. It's been explained that this means there's likely a lot of carbon built up in the motor. Therefore, I'd like to run a motor oil in the engine, either for a little while or perhaps permanently, that will hopefully clean up the motor. I also plan to switch weights and/or brands in hopes of curbing the consumption.

The vehicle used conventional oil - Castrol GTX - from 10-16k miles; synthetic blend - Castrol Syntec Blend and Valvoline Durablend - from 16-50k miles; synthetic - Mobil 1 SJ-rated Tri-Synthetic - from 50-67k miles; and Citgo SuperGard SL-rated conventional oil from 67k-present (almost 75k).

Any suggestions on what oil will help clean things up? I'm thinking one of heavy-duty diesel-oriented oils might be a good idea. E.g. Mobil Delvac (is this the same as the '1300' stuff?), Chevron Delo, Shell Rotella T. I'd like to try something that's readily available off the shelf, which rules out Amsoil, Redline, Sheaffer's, etc.

I'd be willing to run this clean-up oil permanently if cost isn't too high. I'm no longer willing to run extended drain intervals long enough to offset the per-quart cost of synthetics.

armtdm

Suggest trying Schaeffers Neutra, about $3.50 but due to mail order cost may be prohibitive if ordering less then a case.

bluedevils

I presume a respected cleaner additive added to a typical conventional oil would clean things up more quickly and more thoroughly than simply using a high-detergent oil?

The only cleaner additives I've heard NOT characterized as snake oil are Schaeffers Neutra and Auto-RX. I'm not anxious to buy a case (12 containers?) of Neutra, nor am I anxious to lay out 20 bucks for a bottle of Auto-RX. Plus I'm looking for quick results - I can get a good cleansing oil today vs. ordering via phone or Internet for Neutra or Auto-Rx.

malachy72

Delvac 1 is the synthetic, I believe, and Delvac 1300 is the dino. Auto-rx is 3 bottles for 40 bucks for a short time. I'm giving it a try on my accord which has lost a couple of mpgs over the past 6 months as well as some get go. I'll post if I feel/see any difference.

bluedevils

Tonight I bought 3 gallons of this stuff (15W40 - is that the only available weight?). $5.88 a gallon at Wal-Mart seems like a great deal on a good oil. I plan to drop it and a new filter in my oil-eating Trooper for 1,000 miles or so and see if it helps reduce the oil consumption and clean up the motor.

By the way, some of the Chevron Delo 15W40 gallon containers at Wal-Mart, as well as the gallon and quart containers of 15W40 Shell Rotella T, were SJ, not SL rated. The datestamp on some of the containers showed August and September 2001! So if anybody's interested in using SJ instead of SL, some Wal-Marts have plenty of old stock.

It was disappointing to see no 5W30 Chevron Supreme at 2 different Wal-Marts this week. There isn't even a sign for it on the shelves. Both stores did have 10W30 (not a lot) and 10W40 (2-4 cases).

fleetwoodsimca

I think I missed something here. If you are this intent on cleaning up the internal chambers of your engine, you must surely be convinced that it needs it! Please explain. Now, I have cleaned up some dirty engines when I disassembled them. I used old table spoons and putty knives for the removal of sludge, and lesser debris. I must confess I do not think that an engine can really be cleaned without using this approach.

bluedevils

fleetwood, my 98 Isuzu Trooper has 75k miles and is consuming a LOT of oil. I can handle a quart every 2-3k miles, but this engine has gone from well less than 1 qt/3000 miles for the first 10k miles to 1 qt/2500-3000 miles around the 40-60k mark, to 1 qt/1200-1500 miles since 70k or so.

I don't understand at all how combustion engines work, but it's been suggested by a few folks online that an engine consuming lots of oil is very likely, perhaps certain, to have significant carbon buildup.

The engine seems to run fine and I've noted no other 'problems' besides the oil consumption. Fuel economy is in line with other Troopers with this 3.5L engine, no funny noises, no visible signs of oil leaks, no trouble starting, etc. I'm not sure if any of that stuff is relevant.

fleetwoodsimca

Classically, truck engines have been made by some manufacturers with oil shedders on the valve stems that would intentionally allow a lot more oil to flow down the valve stem during engine running, to increase both lubrication and cooling. Oil shedders wear over miles to where they allow more oil to pass down the stems and into the engine where it is burned. As the shedders get "looser and looser" they allow more and more oil to sneak by and get into the combustion chamber. Maybe you need some top end rebuilding? If Alcan could get his paws on that mill of yours... you'd get a real answer from the Canadian Professor.

bluedevils

Yesterday I bought 3 gallons of Mobil Delvac 1300 15W40 oil (not the Delvac 1 synthetic). It's approved for us in gasoline engines but aimed more at the diesel market.

I like the idea of helping to clean out the oil-eating motor in my Trooper with a high-detergent oil such as the Delvac 1300.

Winter here in Michigan typically hits 10-20F for the lows. Occasionally below that but not real often. I'm assuming the truck will start just fine running the 15W40 but I'm a little nervous about excess wear since the 15W40 is quite a bit thicker than I've run in any vehicles.

Also, how will I be able to tell, without doing oil analysis, if I'm subjecting the engine to lots of wear by running the 15W40? Will it be apparent through hard starts, noisy startup, or other obvious signs? How else can one tell?
Any thoughts on this?

gmlover1

I would not run 15w40 this time of year. Why not wait till spring.

adc100

What is the pour point? You will be able to tell by hard cranking and does the light go out quickly. Also lots of noise upon startup is a sign. I suspect those two will be relatively normal.

bluedevils

it's -27F (-33C). Also, some other numbers that may be relevant but which I don't understand:

Pumping viscosity is 19,000 cP at -25C and 52,000 cP at -30C. Cranking viscosity is 6,000 cP at -20C and not rated at -25C.

I changed to this oil a couple hours ago and I'm not expecting any problems during the cold weather here, which is rarely below 0F. I'm really hoping this oil cleans up the motor, and I plan to change the filter and top up the oil after about 1,000 miles. More than the cleaning, I'm hoping for reduced consumption. My last change interval was 3,100 miles with Citgo SuperGard 5W30. My Trooper used 2.5 quarts during the interval, which is a quart every 1200-1300 miles.

My Trooper owner's manual recommends 10W30 unless cold weather is prevalent; then it recommends 5W30. But the manual also shows most common weights, up to 20W50, as being acceptable for various air temperatures. 15W40 is okay for 0F to 100+F.

df2000

I am with gmlover1.Your ZU call for 10W30 year around, but when cold 5w30 is OK. Try search net for 4x4wire and post your ? on isuzu forum.A lot of knowledgeble people(offroaders)there.

fleetwoodsimca

If your owners book says 15W-40 is okay in your temperature range, you've got all the authorization you need, and a need for reducing consumption. I'll bet you will get positive results. Let us know, of course!

malachy72

gmlover really, really , really wants you to wait until spring!

fleetwoodsimca

15W-40 Valvoline All Fleet is doing well in my 6 cylinder Honda 1520cc engine-- in my Valkyrie motorcycle. I switched over from Lubrimatic 10W-40 motorcycle oil, at 6000 miles on the odometer. My point here is that I have faith in the "heavy duty" nature of the 15W-40 diesel qualified, turbo qualified lubes. If I owned a car or truck in which I would be comfortable with that weight, I'd use it without hesitation.

bluedevils

They seem to be pretty good quality, but I'm a little concerned about running a diesel/commercial oil in a gas-powered passenger vehicle. It seems the ash % may be higher than in other oils and there are a couple other things that are still question marks for me - potential to gum up the catalytic converters etc.

At least for a little while, I think the Delvac 1300 will be a good way to clean things up. Today I started the engine cold (probably 35F in my garage) and the engine fired up as quick with the Delvac 1300 15W40 as with the 5W30 Citgo SuperGard that preceded it. Did about 10 miles of city driving and the engine and vehicle seemed to be running the same as before.

bluedevils

After I changed the oil in my vehicle, I started the engine and ran it about 5 seconds then shut it off. I checked the level on the dipstick a couple times in the next 24 hours and was a little puzzled to see such dark oil on the dipstick. The 15W40 Delvac 1300 I used is a nice honey color, but the stuff on the dipstick still looked like older, used, darker oil.

After driving the truck a few miles tonight, I checked the level again and was relieved to see the oil on the dipstick was much closer in color to the fresh oil that was added in yesterday's change.

Is this normal, or does the dark oil on the dipstick immediately after the change suggest that things in the motor are dirtier than they should be?

edwardn1

but I can't help but wonder if the diesel specific components are harmful, benign or helpful in a gasoline engine. Rotella and others like it have extra additives for wear due to the extra pressures a diesel places on the oil due to the compression ignition of the beasts (22:1). I have thought of using Rotella 15w40 dino oil in some of my older cars that burn some oil and are driven short distances, thinking that the extra additives may help with sludge and acids, as these are common in a diesel. Or do the extra additives just take up space in the oil or worse yet form deposits. Keep in mind that some of these additives are for dealing with soot which is probably not a concern in a gas engine. ANY INPUT

fleetwoodsimca

...the diesel competency of the oil as a plus to the gasoline engine. I have never heard any evidence to indicate that the diesel rated oils are inappropriate. The diesel oils are formulated the way they are in order to get some durability for the oil in the very harsh environment of the diesel engine. The gasoline engine is an easy job for this very tough, effective motor oil.

bluedevils

While I agree with you 95% of the time, I've been reading some things from a few fairly knowledgeable, logical folks on another web site that digs much deeper into oil-related matters. Anyway, I haven't seen any evidence indicating that diesel-rated oils are inappropriate or harmful in gasoline engines. However, I have seen some reasonable-sounding ideas that some of the components in these diesel-rated oils aren't always such a good idea in a gasoline engine. Recently, one person posted that they think diesel engines are actually easier on oil than gas engines. I don't remember all the reasoning behind the theory, but one part of it was that diesel engines usually contain more oil (I presume that somehow eases the burden on the engine).

In the back of my mind is a nagging idea that using an oil whose intended primary use is in diesel engines may not be the best thing for a gas engine, even though the oil is approved for gas-engine use. This doesn't scare me to death, as I was willing recently to drop Delvac 1300 into a vehicle that I dearly love and plan to drive for 200k+ miles. But I'm still not convinced it's a great idea to run a diesel oil in a gas engine over the long term.

vadp

Here is a quote from the RedLine Tech Info file:

"The diesel engine oils contain significantly greater detergency and total base number (TBN) which helps keep the engine clean. This additional detergency is not recommended for gasoline engines since it could increase the tendency for spark plug fouling."

bluedevils

I have Delvac 1300 in a 3.5L V56 gas engine right now, primarily for its higher detergency. I'm hoping it helps clean up the engine, although I'm not sure if the engine is dirty. The comment from Redline jives with my suspicions that running diesel oil in a gas engine is not a good plan for the long term.

malachy72

post and I believe he supported your experiment with Delvac 1300. Isn't that oil SL or Sj rated. You're probably right in not wanting to leave it in too long, just long enough to see if the trial can provide some benefit.

fleetwoodsimca

I would never dismiss your sense of caution on this matter. On some engines, fouled spark plugs are hard to get at for cleaning/replacement. There may be other considerations not yet brought to light. Now, what we know as being an accepted fact in the engine world is that diesel engines do not do well on common gasoline engine oils. Diesel engines show special needs beyond the needs of gasoline engines, thus the origination of diesel engine oils. I interpret this to reveal that common motor oil technology is a subset of diesel oil technology. It is not a long stretch to presume that the more encompassing technology will work just fine for all subset conditions. Real world results will tell the tale, and until then, I do not fear using fleet oils like Valvoline, that are recommended for both diesel and gasoline engines.

edwardn1

...and I still have a suspicion that the components that are diesel specific, such as those for soot dispersement, would either take up space in the oil or have some minor or major consequence on something. Additives in gas oils are probably not as likely to foul plugs as the diesel has no plugs. I do wonder if the diesel type oils are better for say an older classic type car that gets driven very little and has a condensation, sludge, water, etc., potential. Thanks, Ed

yurakm

AMSOIL recommends practically the same.

http://www.amsoil.com/products/atm.html

mrdetailer

If it does don't worry about the extra additives. I used Diesel approved oil in conventional gas engines for years without a single problem. The brands I purchased however also had the appropriate SG rating which was the current one.

bluedevils

Fleetwood, I totally agree with your logic in post #2055 - it makes sense to me. Still, I have heard some folks explaining things to the contrary, and I continue to wonder how much concern I should have.

I'm 120 miles and several starts, including a few with the engine being dead cold and air temp around 30-35F, into the Delvac 1300 15W40. Truck seems to run the same with the Delvac as it always has with 5W30. It's a bit early to tell on consumption, but the dipstick does appear to be in the same spot as 120 miles ago. So I'm hopeful that the thicker oil will reduce my consumption.

By the way, the Delvac 1300 15W40 is API SL-approved. Like most other diesel oils, it meets a host of other specs and guidelines that many gas-engine oils don't bother with.

bluedevils

A couple comments swiped from a different message board:

"gasoline engines are much more hard on oil than the diesel engine, turbo or not. Most of that comes from the lack of solvency remaining in reformed gasoline today. Of course a turbo or Supercharged gasoline engine will cook oil faster."

"Most diesels have large(er) sump capacities than do gasoline engines which is one reason why the latter is so tough on oils."

Just some thoughts...

fleetwoodsimca

If the oil is approved for gasoline and diesel engines by the API, I would be willing to accept that as certification enough. I think you're in tall cotton on this one!

edwardn1

consider them. I have wondered about this issue for a few years, either the 15-40 rotella and delvac type oils are really good for a gas engine or there are probably some drawbacks. I do know for a fact based on conservations with lube engineers that they do contain more antiwear, detergents, antiscuff and more additives to deal with acids and water vapor. My sources did not agree on the negative effects of the additives that are diesel only and deal with the soot that a diesel subjects its oil to. I would like to hear a long term report on the effects on a modern gas engine.

fleetwoodsimca

It does not seem logical to think that a soot grabbing additive would create a problem when it does not find much work to do. The oil is in whatever kind of engine, and the additives are in the oil to help it keep the metal surfaces from rubbing each other over a lot of revolutions of the engine before oil change time.

edwardn1

Do you suspect as I do that it is really better than the oil companies want us to think?

fleetwoodsimca

I got lost here. I'm not sure what your reference is. I guess what I am saying is that I am very comfortable with running 15W-40 Valvoline All Fleet Motor Oil in any engine I have that can handle the thicker oil. At present, I use it in my Honda Valkyrie motorcycle. It calls for 10W-40, up to as high as 20W-50 and the 15W-40 is in between those limits.

edwardn1

...that possibly superior oil is why we see big rig diesels with rediculous miles between rebuilds, which is remarkable considering the stresses on a diesel engine. All things equal, they should fall victim to oil breakdown from the forces put on the oil film to create such high compression ratios.

vadp

Diesel engine = tough internals + lubricating properties of the diesel fuel

bluedevils

"Do you suspect as I do that it is really better than the oil companies want us to think?"

I know you weren't asking me, but I think you may have hit the nail on the head. Of course, we don't know for sure.

After 250 miles running Delvac 1300 15W40 in my gas-engine Isuzu Trooper, the truck is still running fine. But that probably doesn't fit your definition of a long-term test

malachy72

May have to open the laboratory for some Delvac in my Civic AWD wagon. It definitely is within the recommended viscosity range.(:>)

malachy72

bobistheoilguy, is going to go 8-9k on a dino batch of oil then post an analysis.

malachy72

to all in 2003!

fleetwoodsimca

I'm beginning to worry...(:o]
And may the new SL year bring you improved additive packages...

edwardn1

Soon we'll have not SL but SM, SN and then we can all complain about having to buy SO SO oil! HAPPY NEW YEAR!

glo22

I have to say this forum is not the easiest to maniuplate. Subject line get so long that it is almost impossible to search thru.

Anyway, I am in Ca. I have an Odyssdy and the manufacturer recommends 5w30. Based on what I read so far, it is to enhance gas mileage with lower viscosity.

Just wondering if I should switch my other cars to also 5w20. Seems like there is really not much harm to use 5w20 instead of 10w30. Actually would there be any problem in switching back and forth between the two viscosity oil. With the lower viscosity, would there be enough lubrication on my car engines???

bluedevils

I'm no expert, but 5W30 isn't as good as thicker oils when air temperatures are higher. There should be no problems in switching back and forth between viscosities in the same engine. Just make sure you are using a viscosity that makes sense in each vehicle (based on mfr's recommendation, driving type, weather, etc.).