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GM ENGINE KNOCK
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Nick, I'm glad you don't work in the service department because your explanation of the piston slap issue indicates a fundamental lack of understanding. You need to stay with sales. Metal, including the pistons and connecting rods expand when hot, not cold. Your theory that the piston is hitting the head is way off base. If that were the case, then it would only get worse as the engine heated up. My understanding of the issue is the type of material and shape of the pistons (hyper-eutectic aluminum alloy and very short skirts) is causing them to rock sideways in the cylinders when cold and clearances are greater. Ford went through this same problem with the 5.4 when it first came out. Also note that Ford 5.4 puts out more torque than a comparable GM 5.3. Shoot, even that little Toyota 4.7L puts out nearly as much torque as the GM 5.3L (315 ft-lbs vs. 325 ft-lbs) and the Toyota does it at a lower more usable RPM. And when you said GM is the #1 motor manufacturer, I assume you meant quantity, not quality.
Alan
Engineer and shade-tree mechanic
so no the 4.7L has no advantage whatsoever over the 5.3L, so why get the 4.7 when you can get a bigger engine with better milege?
Quad we know which one is the best
bigger engine better milage = more efficient
So we should all get the 8.1? Sometimes I truly wonder.......
I held out for a 2001 Yukon when GM repurchased my 99 Sierra. I assumed at the time the 01 would be knock free, since they were tightening the bearings...I was actually surprised when it began knocking just like my 99. Everything I have read or heard is that it is piston slap. I am still unsure if GM is actually going to have a fix for it at this point.
Also in an earlier post someone questioned oil consumption in these engines. My engine doesn't use oil...another reason not to want a dealer to tear down my engine to replace the pistons. I drive only highway miles, I have heard the speculation that only the engines that are run short distances daily have high oil usage. I don't know if I buy that or not. However, I am sure there are a lot of owners out there complaining of high oil usage.
Here, your most influential component in the
timeing is the knock sensor. I would ask them to
verify the operation of the knock sensor.
If your problem is indeed pre-ignition based upon
timeing. Try running higher octane gas and the
problem should be better.
Hope this helps.
My knock has not gone away yet in my 8.1L, but 10 seconds is much more tolerable than the 30-45 seconds it was!!
Bob
http://207.37.252.232/gmc/lr4lm7ben.html
(BTW, thanks tiredofwaiting for that other link)
and today they offered a 5 year/100,000 extended warranty on the motor only. She also said that there will be an official fix coming out in April.
I told her I would have to think about it, what do you all think? Did any of you that did take the extended warranty offer, get it for the whole truck or just the motor?
Clay
their first offer was a 5/75K, and i asked why not 100K since i put about 22-25K miles on it per year. Chris said no problem, as long as i agree not to go after a buyback deal on em. the engine has the rattling sound associated with bearing clearance, but does not burn oil, continues to deliver great fuel mileage, but the diesel like noise you hear when up against a building has increased in respect to when it was new. the service manager that takes care of me, has it documented. new engine would be fine by me.
Seelig
Did you know that Major Guard will reimburse you for a vehicle rental should your dealer decide not to give you one. All you have to do is get a receipt, document the circumstances of why the dealer didn't give you a rental and they will reimburse you. Best one yet was when I filed for reimbursement, I had written as the reason the dealer didn't give me a rental was because "they didn't FEEL like it". That didn't go over well with the folks at Major Guard customer service.....not too sure what happened after as long as I got reimbursed.
Speaking of warranty, when I was going to leave my truck to have the knock checked and documented, they stated I couldn't have a rental car for 24hrs. WTF?? I have to wait 1 business day for them to try to fix it before my bumper to bumper warranty will allow a rental car for me, yet my extended warranty (GM Major Gaurd) will give me one if the repair lasts more than two hours?? Sure makes sense to me....
Bob
All repair work at a dealer has a "Flag"
time. It it the number of hours charged for
a given repair. They are standardized, so if
your repair will only take 1.5 hours and
they cannot get to it in one day. You are out of
luck. If you have several jobs to be done that flag
more than 2 hours total you qualify as well. It is
the same for the GMPP major guard as well.
The Performance section of the magazine tells how to determine which if either of these are the source of noise on the new 8.1. There was a last comment of going to 20W-50 oil on the new 8.1
Think they could then get Bob Seger and the Silver Bullet Band to re-record "Like a Rock" to "Sounds like a Rock"?
Joe
Engine Repair: "Customer states the truck has a cold engine tap on start up and occasionally when warm."
"Checked for bulletins, none found. Called into T.A.N. no fix as yet. Chevrolet is in the process of working on fix."
I can only assume T.A.N. means Technical Assistance Network.
Well at least I'm on record now for whenever GM comes up w/this fix. If it gets worse or just before warranty expires I'll push for the 100,000 mile warranty.
Ray T.
had the truck in 3 times to the dealer where i bought it. every excuse in the book and it still makes the noise - anyone else have any luck getting an answer or a solution to this problem from GM? I thought the 4.8L was improved for 2001 to get rid of this noise? anyone else feel my pain? let me know.
Bob
Just a reminder that the News & Views chat is on tonight (5-6pm Pacific/8-9 pm Eastern). Hope to see you there!
Tonight's topic is On the road again: Your best road trips in 2001!
http://www.edmunds.com/townhall/chat/newsviews.html
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Host
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Is this what Chev meant by "like a rock" - Like a rock rattling around inside your engine?
It sort of sounds like the toy owners, though, when in the past they would say things like, "Who cares that the body is rusted/non existent, at least the motor still purrs like a kitten!!!" Or how about, "The head gasket problems were on the oooold motors and toy did give an extra warranty."
Ford owners were picking on other Ford owners in forums claiming that they should learn to accept their defective trucks. Very similar, sad story.
What fix has Ford developed to eliminate Piston Slap knock?
If your vehicle is still under warranty, Ford will replace your engine at no charge;
99 Model year vehicles will receive a brand new 2000 engine
97-98 Model year vehicles will receive an FQR (remanufactured) engine
It sounds like to me if your warranty expired - you're screwed. Ford took 2 years to admit to this problem so many Ford owners took it in the shorts. Typical Ford schlock quality!
As far as being out of warranty........I have mixed emotions. it seems that if the problem didn't show up within 36,000 miles there could be MANY other things that could have caused the slap/knocking. Lack of maintenance comes to mind.
You sort of need to face some facts yourself there, bama. While skimming your 2 YEAR OLD LINK I couldn't find any Ford owners that said to "accept" the slap/knock" seemed like there were a few happy owners that got brand new motors.
Keep digging.
1. The people posting to this topic have a problem with engine knock. So did the F150.
2. It took Ford over two years to admit to the problem. Does this sound familiar?
3. Ford told owners whose warranty expired in the meantime - Tough Luck!
4. This is coming from the company that did not admit to Firestone tires until many people were killed.
If you don't learn from history, you are destined to repeat it. I think that the GM owners to this site could learn a lot from the Ford piston slap fiasco.
1. Keep documentation of your engine knock issue. Insist that the service dept. write up of your requests to get your knocking fixed. Keep copies of these records while your truck is still in warranty.
2. Keep records of all your phone conversations with the dealer or manufacturer.
3. Don't give up - the manufacturer and the dealer are going to try their best to wear you down on this issue.
Good Luck!
Post 96 was probably the most usable post I've read from you and could be helpful to those who may be getting shafted by dealers/manufacturers. I personally went thru a lemon law buy back w/a GM product in 87, documentation and persistence is what helped me win my case.
Those coments may be appreciated but tooting your horn and bashing GM owners doesn't belong on this board from someone who doesn't own one, we can bash each other quite well on our own thank you!
Ray T.
1) True, but Ford DID acknowledge it and replaced motors. GM is still in denial. Besides, your original comment was that Ford owners had said to live with the knock like some GM owners which is where I called you out. You then found a 2 year old post that said Ford DID replace motors. Sorta shot yourself in the foot there.
2) Admit or fix???
3)Not true if was documented. If the knock came up after 36,000 and you didn't buy the extended warranty you were probably SOL. Did you know you could buy the extended warranty UP TO 36,000 miles?
4)Whole 'nother can of worms. Does deeeep pockets and ignorance have anything to do with the blown out of proportion fiasco?
Read the first paragraph of post #97. It does characterize you to a T.
They're currently offering to cover the engine, if it should fail due to something related to the knocking, for 60 months/60000 miles.
Since I plan on keeping the truck for at least 10 years, I think 72 months/100000 miles is more reasonable.
Does anyone have recommendations on negotiating with GM for extended coverage on engine knocks?
Thank you.
obyone, why should playdough want an extended warranty of either 5/60K (Toyota's standard warranty, BTW) or even 7/100K when Chevy is "The most dependable, longest lasting trucks on the road" ?
HAVE FUN WITH THIS ONE NOW!!!
Why do I have to explain Toyota's warranty to you since it's in front of your face. Geewhiz, dude, take the time out to read your manual...DOH!!
GOOD LUCK ON THIS ONE NOW!!