3100 Malibu running rough

[cardana24]

I picked up my engine today. I hope to start working on the swap this week. Any helpful tips?

[cardana24]

I am leaning towards a direct engine swap. It looks like I can get an entire engine for ~650, and the engine would have over a 100k less than the engine in the car. Once you add up the cost of head gasket replacement, I am guessing I would be at over $100 in parts, plus similar labor time in replacing the entire engine.

[Azrael]

The only way to see where the compression is going without pulling the head off is to do a leak-down test.

There aren't many options for direct engine swaps. The LG8 3100 is the only other engine that will directly drop in but they're far less common. The next closest is the 2005-06 3500's (LX9?) but they require a bit of modification to get some of the electrical and fuel systems working.

[pocket-rocket]

3400 prices vary depending on your area. I think it's a safe bet to gamble on a head gasket. If everything looks fine besides that, I would just get a head set and head bolts and start tearing into it. Do take the heads to be cleaned, pressure checked and decked though. The pressure testing is cheap insurance to make sure there are no cracks, and the cleaning makes them look nice again

[cardana24]

compression results are in
cyl
1 190
3 195
5 30
2 175
4 190
6 175

Soooooo....cylinder 5 is having issues. So it looks like I am looking at a blown head gasket on the number 5 cylinder. Is there anything else it could be? Would it be easier/smarter just to swap out the engine? What is the going price for a 3400, are any other engines direct swaps? Also, what cars use the same engine I need (years and model)?

[cardana24]

Okay, so the car is finally home. It is a 2003 Impala with a 3400. It runs, but rough. It does blow white smoke from the tail pipe and it smells like coolant. I am going to go look into it more now but I was wondering if a bad LIM gasket would cause it to smoke from the tailpipe?

[pocket-rocket]

Engine wise, it's all the same be it an Impala or Malibu.

[cardana24]

So would everything be the same if this car is really a V6 Impala?? I now realize they are not sure which model the car is.

[robertisaar]

any GM engine with the "twin post" coil packs, the coils are the same, so go for it.

[cardana24]

What I am getting at about the compression test is that it compression checks out then it could be the LIM gasket but not the head gasket. I think we are all saying the same thing. Do these newer engines still use the same coil packs that I would have on my 94 camaro 3.4 engine? I have spares of these and I was planning on taking one or two.

[Azrael]

The LIM gasket issue really only affects the sealing around the coolant ports between the head and the manifold. A pressure test of the cooling system and/or a visual inspection of the oil is the only way of knowing for sure. If it's the cause of the rough running then the engine is already far gone enough that just looking under the cap will be enough. It will end up looking like a milkshake.

If it doesn't then continue diagnosing. I agree that the coilpack is a likely suspect.

[robertisaar]

hmm.... compression test can determine a bad headgasket, and using a little pressure tester for the radiator might be able to check LIM integrity.

[cardana24]

Azrael would be referring to LIM gaskets, although head gaskets could do it, LIM gaskets is way more common and almost expected depending on mileage.

Gotcha. It has over 200k miles. What would be the best way to troubleshoot a blown LIM gasket as opposed to a head gasket, am I right in assuming a compression test will point to one or another? Assuming the problem really is a blown gasket?

If it is a blown LIM gasket what work would need to be done other than replacing the gasket?

[pocket-rocket]

Azrael would be referring to LIM gaskets, although head gaskets could do it, LIM gaskets is way more common and almost expected depending on mileage.

[cardana24]

Also check under the oil fill cap and coolant resevoir and make sure there's no cross-contamination of oil and coolant. That's the only real common issue for these motors.

What are you refering to? Blown head gasket or blown intake manifold gasket. I am guessing if it is the head gasket that would show up on the compression test, but if it's a blown intake gasket the compression test should check out. Thanks for the input.