Sc400 Running Horrible..help

[slidekin]

A few months ago I bought a 92 sc400 with 125k on it. Now it smokes from the tail pipes and runs super rough and crapy. I took it to my mechanic and he said I will have to replace or rebuild the engine. Sounds a little extreme to me. I heard it could be the rings or the valve guides from him and other shops. Still way to expensive. I looked on this site and found that other people with this similar problem have had problems with the coils and it seemed to work for them. But I dont see how that could cause smoking from the tail pipes, and that awful gas smell that comes from them. Please HELP I think it s to dangerous to drive so its been sitting in my garage for about a month.

[Sadistic]

If it's smoking, I would say that it's probably burning oil somewhere. If something needs to be replaced, or rebuilt it should be done. Even if it's expensive. There could be other things, but if multiple mechanics are saying the same thing, and they've done diagnostics to figure this out. I would have to say go with what they suggest.

[texsn95]

What color smoke? White = coolant, blue = oil, black = pig rich.

Oh and find a new mechanic if they can't even explain why an engine swap is needed

[slidekin]

As for the first response, they didnt do anything but guess. To find out what is wrong they would have to take the engine apart. That alone is the most expensive part. I have only taken it to two mechanics, in addition to Lexus. The first mechanic said there is a 20% compression loss on all cylynders. And took a guess as to what is happening. I replaces the spark plugs and there is wet oil on one ind the threading and dry on another above the seal line. Also there seems to be oil leaking from the rear main seal. The smoke coming from the tail pipe is white. Which = coolant but why?They have explained why engine swap is needed, b/c its cheaper to replace it tan rebuild Any other suggestions? Coils?

[Sadistic]

Do an oil change on your car. Drain the oil and see if it's frothy, and smells like coolant. Or if you can get a good enough look at it under your oil cap, go for it. It almost sounds like head gasket is starting to go between. That could explain the white smoke. The oil on your plugs (if I read it right) sounds like the valve cover gasket.

[texsn95]

As for the first response, they didnt do anything but guess. To find out what is wrong they would have to take the engine apart. That alone is the most expensive part. I have only taken it to two mechanics, in addition to Lexus. The first mechanic said there is a 20% compression loss on all cylynders.

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So he did a leakdown test then? That's different and more involved than just a compression test, which just shows xxxpsi. Whichever one he did, it helps to have the numbers, then you can compare to spec.

[jzz30]

um did the car run rough all of a sudden? and that smoke does it smell like gas? if these 2 things match then i think 99% that its your coil primary or secondary but you should just chnage both, they range from 75-100bucks from the dealer. if you keep on running like this you will overheat and damage your cats. your oil leak maybe a different case but the plugs are probably just wet with fuel.

[texsn95]

Oil on the spark plug threads are indicative of worn valve guides and/or seals. If they're really bad you'll get a puff of blue smoke on startup. It's not throwing a check engine light?

[SKperformance]

Oil on the thread is from an oil leak form a valve cover usually.

As oil doesn't leak on a plugs thread unless the head is cracked.

Oil on the tips only is a problem but not on the threads.

[texsn95]

Oil on the thread is from an oil leak form a valve cover usually.

As oil doesn't leak on a plugs thread unless the head is cracked.

Oil on the tips only is a problem but not on  the threads.

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Ar, forgot about the valve cover. What I mentioned is common on the pushrod V8s I'm familiar with, but perhaps not with these <_<

[slidekin]

Oil on the thread is from an oil leak form a valve cover usually.

As oil doesn't leak on a plugs thread unless the head is cracked.

Oil on the tips only is a problem but not on  the threads.

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So what your saying is that my head is cracked since there is oil on the threads. :o

[slidekin]

um did the car run rough all of a sudden? and that smoke does it smell like gas? if these 2 things match then i think 99% that its your coil primary or secondary but you should just chnage both, they range from 75-100bucks from the dealer. if you keep on running like this you will overheat and damage your cats. your oil leak maybe a different case but the plugs are probably just wet with fuel.

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I like this idea. Is it hard to do yourself?? Any computer reconfig after?

[jzz30]

not hard to do at all you dont even have to disconnect the battery, no computer reconfig.

[slidekin]

So what exactly do I ask for when I go to Lexus and get the coils. I know there is a diffrent name for them. And how would I find out how to install. Thanks for the help

[jzz30]

just ask for the ignition coils. and its fairly simple to replace you just have to look for them. one is on the driver's side bank of the engine and the other is in the middle of the V you will see coil wires coming out.

but make sure first that you smell raw fuel coming out of the exhaust