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GM ENGINE KNOCK
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So, a longer drivetrain warranty (GMC's is only 3/36K), like Toyota's, certainly would have been of help for playdough.
obyone, you are as sharp as a razor!
My guess would be: He isn't confident it will go 60K or 100K miles without major repairs because of that knocking engine!
What's YOUR answer?
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you will have to wade through the Pluto/Bama garbage though......sorry, it seems we hvae children posting in here at times.
b
See, Toyota actually learns from the few mistakes it has made, like the head gaskets, and fixes the problem.
But GMC just continues to crank out engines that knock, then fights people tooth and nail when they want the problem fixed. GMC CAN'T fix it, that's why they're offering extended warranties.
At any rate, who wants to spend $30K on a truck whose engine knocks, even if GMC decides to extend your warranty?
If I wanted an engine that knocks, I'd buy a diesel for crying out loud, and get the longer warranty that diesels come with in the first place, LOL!
Have fun with THAT one, now!!!
It seems that history is repeating itself. I would suggest that GM Knock owners visit the F10online website and do a search on "Piston Slap". I am sure that GM owners will learn some lessons. Ford terribly mishandled this problem, I would hope that GM would do better!
It seems to me that there are alot of people that are complaining
about the noise and I have yet to hear of a knock related failure.
I also hear Toy owners trying to make a mountain out of a molehill
regarding this issue. Basically people that need to get a life.
Could it be that the Piston Slap is just an Annoyance?
GM has acknowledged the issue in TSBs
GM does not have a solution yet. What are they going to tell you?
The engine is working as it was designed.
No doubt that GM will come out with a fix soon, and it will be a
repair for a "Customer annoyance Issue".
Just keep in mind that any solution to this issue will have to be
well engineered and that takes time. Time for testing in the field as well
as Destructive testing.
Seriously, I think many of you have been brainwashed by obyone, owner of the Chevy in the shop 4+ months who continually brags about his truck.
we'll find out.
at any rate, you two have got to be the most antagonizing poster(s) on this forum. you obviously don't have lives, and this consistent stalking of Obyone, and the way you put up posts and then delete (name calling) has gone way beyond what's known to be abnormal. i know it's better to just ignore immaturity, and you two (or one) certainly aren't taken seriously, but your foolishness is really getting on peoples nerves.
if you own trucks that are trouble free, then we are all glad for you, but some people i talk to on other forums have gone there because the nonsense you cause here is simply chasing people away from Edmunds. good job........i'm sure that Edmunds is real proud of you.
I will refrain from posting in this thead from now on, however, as I can speak from experience how annoying it is when the likes of tbunder, obyone, quadrunner500, stang, etc. keep posting in our Toyota threads.
There. I am acting like the adult here. Let's see if the likes of tbunder, obyone, quadrunner500, stang, etc. do the same. Doubtful.
4.8 who? / 4.8 in shop again for engine noise ,once again they tried to tell me it was from too high an octane fuel but told them I switched to low grade fuel last summer on their advice with no change. I also have hard starting condition warm ,starts fine when cold but cranks for a while after engine is warm. Ed
Nothing. The truck was in excellent shape inside and out. It unfortunately
was a 2wd and I wanted 4wd. So I upgraded. 2001 Chevy Silverado. No knock.
I will say this. There is no substitute for a good dealer and an excellent
service writer. Too many of the service writers out there are boneheads.
They don't know s*** and they guess when they don't know the answer.
I am lucky to know serveral in the business that are former mechanics.
These are the ones that know what they are doing. They know who to talk to
to get the answers.
In any case I would rather deal with a Bonehead Chevy service writer than the
many arrogant take it or leave it Toyota Service writers. My wife having owned a Toyota
passenger car in the past, I had first hand experience with the idiots in several Toyota
service departments.
-- Don
are going to be a reality. Just got off
of a conference call with a local service manager
and the regional field engineer.
GM has produced 500 sets of these specially coated
pistons and installed them in field tests.
In every case these pistons have solved the problem.
The pistons are made by a third party, that due
to the production requirements, had to build a new
production facility. This new facility is
scheduled to open first quarter next year.
When I asked if there had been any issues of
longevity with the current pistons, the reply
was "none reported."
Some dealers have replaced motors for complaining
customers only to have the piston slap come back.
Now these dealers are having to eat the cost of the
motor as well as deal with a possible buy back
based upon the lemon law. As I was told, GM has
tied the dealers hands regarding this issue only
to tell them that a fix is in progress.
As I also understand, this will not be a recall
as it does not affect longevity of the motor. It
will be based upon customer complaint.
GM went with the current design in order to
help their CAFE requirements. Less drag from the
piston skirt equals better fuel mileage. What
they did not count on was the consumer backlash
from the resulting piston slap.
They also asked me which brand of gas I was
using. Apparently Chevron gas is the best for
the 5.3 l motor. A certain gas suppliers product
has produced alot of carbon build up on the pistons
and valves.
Who knows what we will see.
Take it for what it is worth.
who are threatening with a Buy Back. It is a tough decision, Live with the Piston slap
or let some engine tech go through it?
The new pistons were not designed for mileage but to reduce the piston slap without affecting
the current mileage. Only time will tell.
http://www.c5registry.com./2k2z06/page5.htm
Ray T.
Truck 5.3 Vortec is going the same route.
The only engine replacement I would suggest is one that already has the new pistons in it.
Walter
It sounds like a bad lifter or something - is it really piston slap? very annoying.
dealer runs fuel injector cleaner for it, comes up with all kinds of excuses.
If it is as loud as you state, there must be something wrong.
To some of us it is extremely loud yet others may never hear the
same sound from the same engine. Try to compare it to a like
vehicle.
Cold engines have oil at the bottom of the pan and until the oil runs through the engine, then you will hear clatter and noise.
You have a problem if the engine is warm and you get knock or you get knock under load.
From what I understand, that is what you have.
Thanks.
tep
Manufacturers like 5W30 (or 10W20 in a Ford) because it helps bump up their CAFE (Corporate Average Fuel Economy) numbers a little, which are mandated by law.
The synthetic oil actually has much better ability to adhere to surfaces for a longer period of time. The Air Force has been using it extensively, especially in engines (gas and turbine) exposed to near-zero and sub-zero climates for years. SAE testing has clearly verifyed the superior coating qualities of synthetic oils.
Good luck!
Joe
Oh, you didn't know that it is the truck's GVWR that determines if it is considered for CAFE ratings, and not the size of the engine? Too bad....guess you were too busy trying to be funny at someone else's expense to bother checking the facts. Wow...you could work for CNN with credentials like that!
And, oh, by the way, the way to refer to an oil's SAE rating is 5W30, or 5W20, not 5-20.
You suggested to TEP that "SAE testing has clearly verifyed the superior coating qualities of synthetic oils." Then why would he have a more pronounced "knock & clatter" after this recent switch to the more superior synthetic??
Curious minds what to know !
I am not convinced to switch to the more expensive synthetic oils, the only one benefitting from it is stockholders and oil company CEO's.
Don't mind modvptnl comments, silence is deafening!
Ray T.
The reason I brought up the V10 was your comment here;
Manufacturers like 5W30 (or 10W20 in a Ford) because it helps bump up their CAFE (Corporate Average Fuel Economy) numbers a little, which are mandated by law.
-------------------------------------------------
Of course I know that CAFE is based on GVW. You can't get the V10 in anything but the 3/4 ton and up chassis. Your sales comment has nothing to do with the V10 and its 5-20 recommendation for CAFE reasons. Understand yet???
I'll try it a more simple gentle way. Why would 5-20 be recommended for the V10 when it AND THE CHASSIS it's in isn't subject to CAFE???
BTW, "arguement" is spelled argument.
Let's get our ducks in order next time before we try correcting other people...
-------------------------------------------------
And, oh, by the way, it is STILL 5W20, not 5-20.
And, as I said, I never even brought up the Ford V10; I just made reference to the fact that Ford recommends 5W20 in many of its engines rather than GM's preference of 5W30.
If you admit that the V10 isn't included in the CAFE calculations, why did you bring it up? I didn't mention the GM truch models also not included in the CAFE.
The Toyota crying chat room is down the hall and to the left.
See ya!
You said the "REASON" was CAFE for the 5-20. I'm simply asking why Ford would recommend 5-20 in motors that aren't subject to CAFE.
Guess what? The 5.4 V8 in the Super Duties (3/4 and up) also recommens 5-20. They, also, are not subject to CAFE.
Is this the twilight zone???
If the reason for 5-20/5-30 is CAFE as you so eloquently stated in your first post(mentioning Ford I might add) Why do motors not subject to CAFE run it???? I'm trying to let you save face here, instead you keep with the stupid, meaningless corrections and toy comments. I guess that's what people do when they're wrong.
What is recommended for the 8.1? If it's also 5-30 I think that also shoots your CAFE theory all to heck. Same with the 6.0, does it have different oil recommendations for 1/2 and 3/4 ton? So forget the Ford motors. Does GM have different recommendations for their CAFE exempt vehicles?
Oh, and BTW, "truch" is spelled trucK. Dohhhhhh.
Whey you go to the parts store, be sure and ask them for 5 DASH 20 oil. When they tell you they only have 5W20 or 5W30, guess you'll have to settle for that.
By the way, yes, Chevy does recommend 5W-30 in the 8.1!
Jeff
I should have mentioned that I switched to the 5W-30 Mobil 1 from 5W-30 Pennzoil conventional oil (Duraguard filter). I've only changed the oil twice. I'm not sure what the engine ships with, but I suspect it is also conventional 5W-30 oil.
tep
What's funny is that Honda also recommends 5-20 and there isn't one car in their line up that gets under the CAFE.
ruud, I apologize about the rantings. I simply stated a disagreement with a hot head. If the 8.1, which is exempt from CAFE BECAUSE of the GVW, runs 5-30, why would GM state to run a lower viscosity just for fuel economy if it doesn't count against their average?
PitAman, I actually am quite able to get my own oil off the shelf. Stop being so anal and defensive. Sorry I disagree with you about the CAFE being the reason. From now on, everything you say shall be gospel(even if you spell it wrong) LOL!!!
From now on, I will try to offer constructive advice ONLY to those asking for help, and ignore the ramblings and offensive attempts to sound funny at someone else's expense made by non-GM owners here in a GM forum.
As for my reactions, I apologize only to those looking for assistance here in the forum. I'll not fall into such a silly juvenile trap again in the future.
TEP: As for the oil shipped from the factory, I was once told by a GM rep that the engines are usually shipped with a slightly heavier oil to aid break-in. The one exception I know of are the Corvette engines shipped with Mobil 1 from the factory.
Joe
Peter
They did the same thing with the conversion from R-12 to R-134a refrigerant in their A/C systems.
When they changed paint from a lacquer to enamel-based paints, they changed out entire factory at the same time so that all models made in that factory were painted with the same type of paint.
GM has also used many other standardized items, such as the same or virtually the same radios, brake pads, windshields and other non-body items in similar models.
Now, any theory on what I asked the other day, "You suggested to TEP that "SAE testing has clearly verified the superior coating qualities of synthetic oils." Then why would he have a more pronounced "knock & clatter" after this recent switch to the more superior synthetic??"
I can't figure it since 5w30 is 5w30 whether synthetic or not the viscosity is the same.
Ray T.
PitAman, sorry my original pun hurt your delicate, sensitive feelings. Ray has now asked twice for your constructive advice. We all await anxiously for your profound wisdom.
You really are acting like a spoiled baby that just won't shut up. Between the fact that you don't own a GM truck, and you seem to be more interested in trying to sound funny rather than make any substantial contribution to the conversation, I have trouble finding any LEGITIMATE reason for you to be in here.
To the REAL Chevy owners,
As for the original question, I have a couple of suspicions, but I'm going to ask a friend of mine that owns his own auto repair business, has 20+ years of repair experience, does TWO radio call-in shows for auto repair; one on a San Antonio station, and one in Houston. He also owns a '99 Chevy Silverado with the 5.3 engine. I suspect that he will point to the filter, which may not have the correct anti-drainback valve, causing the engine to start with a near-empty oil filter the first thing in the morning. The other cause may be the detergents in the synthetic oil loosening some deposits in the engine and partially blocking an oil passage.
When I get the information, I'll gladly provide it to anyone that would like to find out what he said. However, I won't be bothering to post it in here; I've learned from experience that the best way to deal with an unruly baby is to not give them what they want the most. In the case of the little boy named Jason, it seems to be attention at someone else's expense.
Anyone wanting to know what he says can e-mail me. I'll be glad to help any Chevy owner with an engine problem.
Joe
your info is most interesting, and don't worry about the puns. considering who they come from, they hold little value. no apology needed.
What's funny is that your drain back valve theory may be the culprit. But like CAFE you have the mechanics wrong. The valve keeps the oil from draining from the oil passages, not the filter. A bad valve lets oil back in the filter FROM the motor. Like Eric stated, once started, your filter is usually full. I apologize in advance if doubting your wisdom insults you in any way.
Stop winking, mike. I know you miss tim and all but I don't think Joe will let you have a sleep over.