GM 4.3 L 6 cyl - Noisy Lifters?

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pmt

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I bought my 2003 GMC 1/2 ton pickup new. 80 - 90% of miles are on the highway. OCI has been 5000 mi, using synthetics (M1 5W-30, GC 0W-30, Havoline Synth 5W-30, and PP 5W-30). Total miles on truck are about 81,000. Not sure when I first started to notice the lifter noise - maybe the last year or so.
A guy I knew where I used to work had a late model S10 with the same engine. He said he'd had no problems with the truck except for noisy lifters. He also did mostly highway driving and used synthetic oil - I'm not sure of oil brand or OCI. I do know that his truck at the time had well under 100,000 miles on it.
Do the GM roller lifter 4.3 L engines have a reputation for developing noisy lifters at so few miles? I would think that a roller lifter design would have very low wear rates compared to the many flat bottom lifter Chevy small block V-8s I have driven through the years. So this doesn't make any sense to me. Thanks for any input.
 
My OHV 2.2 roller-cam has noisy lifters too. It really started with the last OCI with maxlife. I'm hoping maybe there was gunk built up inside the Hydraulic lifters and the maxlife just cleaned it out and it needs flushed. If not, it's not a big deal. A tappy tappet is a happy tappet as they say.
 
Does it make this noise at start up and then go away when warm?

I have heard of both lifter noise and piston slap occuring in the 4.3
 
mine was fine untill i started getting it gummed up by seeping antifreeze into the oil due to an intake manifold gasket. Fixed the gasket, but engine has not been as quiet since.
 
My 1996 is quiet @ 260k and my 2004 is quiet @ 119k.

The 1996 has only seen 5w-30 and 10w-30 and the new to me 2004 is running on 5w-30.

The 1996 has never been apart and it looks like the 2004 is still all original.

I've always found the 4.3 to be quiet and was happy when I found another.

Take care, Bill
 
My 4.3L lifter noise is there when started cold and doesn't change much as it warms up. I had an 85 Monte Carlo with a 4.3L (flat bottom lifters, not rollers) and when I stopped driving it at 249,000 miles due to rusted out body the lifters were still quiet.
It seems like the 4.3L engines have a lot of variability in lifter noise, as they do in whether they vibrate or not. The one in my 2003 GMC has vibrated from new noticeably between 1000 and 1500 rpm when driving. Of course my GM dealer's service dept said, "All the 4.3L sixes do that." No - they don't. Many guys I know with 4.3Ls in pickups and vans say their engines are perfectly smooth. But on some websites you can read others complaining about rough 4.3Ls. GM quality control I guess.
 
The 2 4.3's I had (1994 and 1998) were always quiet. The 1998 piston slapped like a mofo on cold start, but quieted after 30sec or so. On the 1990 4.3L my dad owned for many years, it developed a nasty lifter tick one time after a ~5hr hywy run. I did an oil/filter change on it, it went away and never came back. I just assumed a pc of debris clogged and collapsed a lifter, I got lucky with new oil flushing it out? Dunno. This was a good 10yrs ago.

Joel
 
brother of mine has a 91 4.3L and lifters are quiet!
also for the record his does not vibrate, and this is significant because they added the balance shaft in 1992? mike
 
My 2002 ZR2 has a very quiet top end BUT I would bet the sound you are hearing is your balance shaft. The 96+ 4.3s had noisy balance shafts. It almost sounded like the bolts on the cat shield were vibrating a tad bit. This normal for these engines. There is a TSB for solving this noise but requires ripping off the timing cover which is not worth it in my opinion.
 
Originally Posted By: muffinstew
My 2002 ZR2 has a very quiet top end BUT I would bet the sound you are hearing is your balance shaft. The 96+ 4.3s had noisy balance shafts. It almost sounded like the bolts on the cat shield were vibrating a tad bit. This normal for these engines. There is a TSB for solving this noise but requires ripping off the timing cover which is not worth it in my opinion.


My '99 had the same issue.
 
My son had a 96 Blazer with the same engine, he bought it used. It had a slight lifter noise, I added a qt of MMO to the oil, the noise went away. We kept the Blazer for 3 years, I sold it to a friend 3 years ago and he swears it is the best running vehicle he's ever owned. It has well over 150,000 miles on it and is now driven very hard.
 
Originally Posted By: pmt
I bought my 2003 GMC 1/2 ton pickup new. 80 - 90% of miles are on the highway. OCI has been 5000 mi, using synthetics (M1 5W-30, GC 0W-30, Havoline Synth 5W-30, and PP 5W-30). Total miles on truck are about 81,000. Not sure when I first started to notice the lifter noise - maybe the last year or so.
A guy I knew where I used to work had a late model S10 with the same engine. He said he'd had no problems with the truck except for noisy lifters. He also did mostly highway driving and used synthetic oil - I'm not sure of oil brand or OCI. I do know that his truck at the time had well under 100,000 miles on it.
Do the GM roller lifter 4.3 L engines have a reputation for developing noisy lifters at so few miles? I would think that a roller lifter design would have very low wear rates compared to the many flat bottom lifter Chevy small block V-8s I have driven through the years. So this doesn't make any sense to me. Thanks for any input.

GM had to replace a number of the 4.3 S-10s because of lifter niose. Most that had the issue did it early on in the engine's life. I've sent two to the local Chevy dealer that had less than 30K on them. They put new short blocks in both. No explanation as to what was wrong either. Usually, when the manufacter opts to put a new short block in it's because there's a machining problem with the block and not a simple pressure-related problem. The 4.3L has been one of GM's bright spots in an otherwise dark world. Very torquey v-6 without alot of problems.
 
To: muffinstew

Do you happen to know which side of the engine the balance shaft is located? My "lifter" noise seems to be confined to the passenger side of my 4.3L 6 cylinder. Nothing much from the driver side.
Thanks
pmt
 
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