05 Tahoe, started making a noise, loud when cold, quiet to nothing when warm, sounds exactly like the lifter noise shown on various YouTubes and such. Mechanic tried oil flush and change now quotes $4100 to pull the heads and repair or $7500 for a new engine with a warranty - both seem high to me and extreme for the problem.
All I can offer is what I might do. I would go up a weight in motor ( 10w30 to 10w40 ) maybe add some engine snake oil ( some kind of additive ) . Now if this Tahoe is in really good shape and suits your needs then a new engine with warranty is a choice only you can make.
Proper diagnosis for a proper job, similar car, similar issue, ended up being a bad tensioner, old school shade tree mechanic I am, got fooled, but my shop was on it and fixed it for way less than a new engine.
Go to your search engine, and enter, 2005 Tahoe Piston Slap
Should also mention that its only got 80k miles on it.
Check with your Chevy Dealership, from what I see there’s a customer interest bulletin about valve train noise on this vehicle. PIP4138P. A collapsed lifter is one of the potential problems mentioned. Often the manufacturer will provide the necessary service as an extended warranty for customer interest bulletins, or at least offer a discount. No harm asking anyways.
I wonder if your oil filter may have.a.defective check valve and is allowing the oil that would normally remain in the filter to drain back into the crankcase. On a cold.start, the oil filter has to be refilled and allows less oil to get to the lifters. Be sure to use a name brand filter when you have the oil changed and if you aren’t doing your own oil changes, have the job done by a reputable independent shop or.dealer and avoid the oil change chains.
Also, I wouldn’t go to a heavier oil than your manual recommends. You want the oil to flow.freely when the engine is cold.
At any rate, get a second opinion.
These engines regularly go 250,000 miles with reasonable service. Agree with @Tester This is classic piston slap. Loose tolerance when cold, tightens up when hot. Annoying but harmless. Ignore it. I had this on an '02 5.3 liter Chevy V8.
BTW Your mechanic is trying to make his boat payment. This engines are so reliable, they are cheap in the junkyard with lower miles than your. A 35K used motor swap would cost you less, way less than the $4100 he wants for the heads.
If the noise is piston slap, I wouldn’t worry about it. I still think it might be.lifters. I had lifter.noise on my 1954 Buick,. particularly in the late.fsll and early spring. I used straight weight oil, 30 weight in the summer,.20.weight in the fall and spring and 10 weight in the winter. Even after I became a convert.to 10W-30, I would.occasionally get lifter.noisr starting my Buick,.or my later Ramble.Classic.and.Maverick in extremely cold weather.
I wouldn’t worry about a.little lifter noise or piston slap on an engine if the noise goes away as.the engine warms up.
Add a bottle of Lucas engine treatment to your oil. It works wonders for my wife’s Acura with 240K miles on it. No more lifter noise on cold startup.
This is actually good advice. The internet is swamped with complaints about piston slap on Chevy engines of this vintage. It’s a very well known problem. Most techs attribute it to piston skirts that are too short, however the location of the wrist pin axis relative to the piston size, the location of the wrist pin relative to the piston’s top surface, the configuration of the piston top, the combustion flamefront, the stroke, and other issues are all key parts of the equation. It isn’t as simple IMHO as just the piston skirt. I suspect that deep, deep in the bowels of the GM engineering department there exists a few guys that have determined exactly why piston slap occurred, and I suspect it’s all been reported to management (although probably not in writing), but we the consuming public will never know the whole true story. All manufacturers of any size have company secrets, and I suspect this is one of GM’s.
Note that I’m not suggesting not getting further diagnosis. I’m only agreeing that it may well be the infamous piston slap, and if it is there’s no cure.
Maybe an oil pressure check with an external manual gauge would be a good idea. If the oil pressure sucks then a replacement engine or vehicle may be in your future.
As for only having 80k miles, that means nothing. Depending upon the oil change regimen, etc, it’s quite common for 80k miles engines (and even engines with far less miles) to suffer major issues. Many have died premature deaths at way under 30 or 40k miles. Sadly…
Agree completely. Likely a decision made to reduce friction to improve MPGs. There is a trade-off between piston skirt length, wrist pin offset and piston clearance that help MPGs but make noise.
Back in the 60’s piston slap on startup was far more common on performance engine delivered with forged pistons. Especially on big bore (big block) engine. Add solid lifter clatter to that and the engine makes quite a racket until it heats up. Hypereutectic cast pistons have been installed with very tight clearances for quiet operation plus hydraulic lifters so we got very used to that silent startup.
Many thanks to all - I’m going to pick it up from the mechanic and take it to someone else (probably the local chevy dealer) for a second opinion and see where we go from here - at the very least I’m going to lean on the mechanic to bring the cost down.