I will be replacing the lifters in a 2003 6L Chevy Suburban engine with almost 300K miles. What is a recommended brand name of lifter that I should get for lifter replacement in this engine?
Thanks all.....

Larry,
If the lifter is just noisy, it may just be gummed up. That be the case, you might do a change to a lighter weight synthetic for at least one change. It may get in there and make it quiet down a little. Sure is easier than pulling the heads.
Matt

Matt,
It is noisy on cold start-up. Clattering goes away in about a minute of running. Oil is Mobil 1 0W40. Then starts clattering again when running down the freeway at 2100 rpm for 10-15 minutes. Clatter eventually goes away when off the freeway in 30-40mph traffic. Oil pressure runs at 30-35 cold start, and gains to 40 at hwy speeds. The warmer the engine gets, seems to gain 2-3lbs. Son-in law has made regular 3K oil changes since new with only Mobil 1 oils. I don't think it is a gummed up issue. Seems like lifters that are just worn out. JWIT. Thanks for the suggestion.

After 20 years, it might be a good idea to have a look under the valve covers.
Don‘t forget to replace the valve cover rubber gasket. Order them beforehand.

Dominik wrote on Fri, 06 January 2023 15:49

After 20 years, it might be a good idea to have a look under the valve covers.
Don‘t forget to replace the valve cover rubber gasket. Order them beforehand.

Dominik,

Did you ever find a GMC to buy?

The GM 6.0 was one of their most robust engines (probably why the discontinued it). The only thing Larry could do under the cylinder head covers might be the valve guide seals. But in this engine series, he is more likely to loose a coil pack. If I remember correctly, there is also enough top FEAD on the engine to make removing the head covers a real bear AND (depending on the assembly plant - there were 2), it could have formed in place gaskets. Those are famous for leaking if not applied on automated line at St.Katherines (PO).

If it is just being noisy, Larry is better off just turning the radio up.

Matt - the refugee from dyno-land

I'm sorry, I don't mean to be assumptive with my suggestions – I just spent hundreds of dollars (actually, swiss francs) and hundreds of hours replacing parts on a 1988 Chrysler 3.0 Liter engine (Mitsubishi), and am still having the same knocking problems as I had from the start. Just trying to save Larry from replacing parts that are fine – Like me, replacing the Lash Adjusters twice to no avail...
I tried to leave out the technical questions to my old Chrysler minivan from the GMC Motorhome forum, but if they're welcome, I'll gladly ask.

Best wishes, have a safe and healthy new year;
Dominik

Matt I’m assuming the 4.0 I-6 wrist pin knock is nothing to worry about? My 99 XJ is at 321,000 and it’s noticeable only when I first pull to end of driveway and get out to get the mail. Not enough to hear in the vehicle. My Cinnabar built 455 on the other hand has cold start piston slap (only hear 1) at cold starts. It goes away after a couple mins. Assuming better than too tight? About 15,000 on the 455.

Back in early January of 2023 Idid a post entitled "Lifter recommendation" and wanted to let those interested (especially Carl Stouffer ) what happened.

Here is the post:

I will be replacing the lifters in a 2003 6L Chevy Suburban engine with almost 300K miles. What is a recommended brand name of lifter that I should get for lifter replacement in this engine?
Thanks all.....

Larry
78 Royale w/500 Caddy
Menomonie, WI.

Here is Carls response.

Larry,

I have a 2006 C-20 HD work truck with the 6.0 engine in it. Some time back, this truck (with just under 200,000 miles on the clock) was doing the same thing you are describing. Along with the lifter clattering at startup, it also had somewhat low oil pressure, which got better as it warmed up.

The initial diagnosis was that it maybe needed a new oil pump, but my mechanic fiend wanted to try something else first. He said his previous experience with this same issue showed that the oil pump was generally okay but he theorized that the problem was the O-ring seal at the oil pickup. His thinking was that it was leaking when it was cold and as it warmed up, it would swell just enough to seal up.

Since the oil pan is easy to access on this truck, he wanted to try just changing that O-ring instead of doing the much more involved, and expensive, oil pump job. I was willing to take a chance on it and he dropped the pan and changed out the o-ring. That immediately fixed the problem. The truck has good oil pressure and NO lifter noise right from a cold startup and runs like new.

Chances are you are experiencing the same problem and a simple O-ring change might be the fix.

Carl Stouffer '75 ex Palm Beach Tucson, AZ


As a result of Carls response, researching the "O" ring change I found this to be a very common problem with high milage LS GM engines. I bought the pan gasket, "O" ring, and Oil cooler gasket, and spent two days dropping pan and Oil pick-up tube to find that the O ring had hardened up, and shrunk in size. Replaced the O ring and put it back together. Oil pressure has increased from around 35psi at a hot run, to 60psi at a hot run. No start-up lifter clatter, and no lifter clatter after running on the highway for 30 minutes or so. Oil pressure is now steady instead of varying from 20-40psi at random. Anyway, THANKS CARL STOUFFER. Saved me a lot of trouble and now potential for reaching 400K miles.

Back in early January of 2023 Idid a post entitled "Lifter recommendation" and wanted to let those interested (especially Carl Stouffer ) what happened.

You're welcome! Relatively simple fix, wasn't it.

Ok, I'll bite, what's this "Front Pumpkin" thing of which you speak?

That ment dropping the front pumpkin which made "JUST" enough room to juggle the pan out.