I was pricing parts today and someone from Autozone asked me what I was doing with the car (I was asking for some parts pricing).

I described one of the issues which is, I have oil sludge build-on the engine block. (See Pic) ...Basically all over the engine. It is caked on there pretty good. They said that the LIM Gaskets were probably faulty because of some change in the fluid chemicals with the coolant / oil from GM. And that after about 100K miles the gasket was eaten away by it. And probably needed to be replaced. I don't mind doing it if it really is the issue, but i'm not really convinced. They said that if it looks wet, it's a oil/coolant combo. It does somewhat look wet in certain spots, but I guess it never occured to me that it was more than oil.

I thought the LIM issues occured with S/C 3800s not with N/A engines???

Can you gurus please take a look at the pic and give your opinion? I can take more pics if needed. What causes the oil sludge build up on the engine below?

At some point, I dont know how long ago and it may still be an issue, but at some point the N/A engines had an issue with the Intake manifold (the black piece on top of the engine) warping and leaking coolant into the engine. My understanding was that it was due to heat from the EGR, which supposedly was later corrected by putting a shield around the EGR.

I have not heard of any issues with the N/A engine LIM, though that may not mean much.

That all said, looking at your picture, Im thinking your issue is more valve cover gasket related than anything. Is the back side of the engine the same way? Id be given that baby a long, detailed steam bath.

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Scotty Hall
Bartlesville, OK
2001 Pontiac Grand Prix GTP
It whines a lot, but I like it.

The only limitation you will ever face in life is yourself!

Not sure where you read that, but the S/C and N/A engines use the same crappy paper LIM gaskets. The gaskets on my N/A 3800 started leaking coolant onto the bell housing at around 50k. I've since replaced them with the newer aluminum gaskets and all is well.

Not sure if that's specifically the problem you're seeing, but it is probably contributing. If 100k miles are on the engine I guarantee they're leaking. I've seen them leak in a variety of ways from oil mixing with coolant, coolant mixing in to the oil, oil pooling on the LIM area, coolant dripping down the block, etc.

For what it's worth, the guy was wrong about one thing. The gaskets are not "eaten" by anything. They fail over time as a fact of a faulty design. That's why GM redesigned the gaskets, not changed the fluids used. If you've ever installed the new gaskets you see why they don't fail. They're thick and rigid and the stock gaskets are complete crap when you take them off.

Anyway, hope this helps.

Edit: Here's what the new gaskets look like...

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2004 Impala LS - got some mods
NAIOA Moderator

Making you think twice before picking on Impalas

va;ve covers from what i can see. tske snother pic of the upper intake manifold if possible so we can see what that looks like.

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1999 Silver GTP~HP Tuners~XP cam~ZZP FS Intercooler~#4 FMHE~ZZP 78mm Billet Throttlebody~LQ4 MAF~Lucas 42.5's~ZZP SS Headers~2.8 MPS~PRJ fuel logs~Ported & Polished S/C~JMB fwi ~Built Tranny-3.29's-7/8's chain-Intense forged Input Shaft~

Running mid-high 12's

Agreed on the Valve covers! they wear out over time and get pretty melted flat....even being on the N/A motors.

best way.....scrape all the sludge off by hand....all the big clumps anyway.

then get some dawn soap and a rag.....then finally go in with some degreaser.


EDIT: also looks like your oil pna gasket may need replaced..I see a little bit of fresh oil on the sludge..

To clarify a few things. ALL GM engines produced in the mid 90's that had went to the plastic style intake gaskets failed. Partially due to heat, and partially due to a reaction with Dex-Cool. They basically pushed too much on R&D, and used an inferior material to make the gaskets. When this happens, the plastic softens and causes a coolant leak.

On the picture, I'd agree on the Valve cover gaskets are probably gone, and the Oil pan gasket probably should be replaced on it as well.

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GreenBastardPerformance2000 GTP Coupe (the green bastard)
XP, Pacesetters, LS1 TB & MAF,MSD System, P&P LIM, P&P GenV w/ 3.2, 3.0, 2.8, Devil'sOwn Injected 100% Methanol,PowerTuned, TripleEdge Trans w/3.29's
12.92 @ 105mph

X2

A good washing with a brush and solvent would be a good idea as well before and after those parts are fixed/replaced.

~F~

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