MasterTomos

iTrader: (15)

My buddy blew a headgasket in his '95 LT1 Z28. He let the motor cool down and then drove it home about 15 miles. It ran hot the whole way home, but never got into the red on the temp gauge. About 3 blocks from home, the car died, but then started up again while coasting and then died in the driveway.

The serp belt and everything spins so I dont think the motor is locked up or anything like that. but what else could it be? I was thinking maybe the ICM?

thanks for any input.

BowtieGirlZ28

Why is it overheating? If the water pump is leaking it is possible the opti got wet, and that can cause what you are describing.

BowtieGirlZ28

Is he sure it's a blown gasket???

Badazz 97 TA

iTrader: (18)

How do you go from a blown headgasket and then assume the ICM is the issue because the car wont start? i dont get it. Does the oil look milky?

MasterTomos

iTrader: (15)

Pretty positive its a headgasket. It smoked like crazy out of the exhaust before it was parked (before the cool down) and exhaust was bubbling out of the radiator when the cap was off.

ICM's go bad due to heat many times, hence why people do the ICM cooling mod. Its still got the oem ICM with 100k+ miles.

Oil doesn't look milky, but pretty positive there is exhaust in the coolant.

RamAir95TA

iTrader: (2)

I've seen a number of instances where a severe overheating has caused failure of some electronic component within the vicinity of heat, namely the ICM, coil, and opti.

MasterTomos

iTrader: (15)

^so im not crazy for thinking this. Good

Badazz 97 TA

iTrader: (18)

ok fair enough. makes sense. haha

Paul Bell

iTrader: (9)

As you were suspecting the ICM from your opening post, did you check for spark with a test spark plug directly from the coil during cranking? This would be the first test on the list.

How many miles on this car? Any coolant in the oil? You can check this by looking at it's level.

MasterTomos

iTrader: (15)

It boiled some of the coolant out of the overflow-so it is low. No coolant in the oil, however.

Havent tested a plug yet. Never done that before, assuming you just pull the plug with a wire on it and put it on something metal and crank the motor?

Paul Bell

iTrader: (9)

You get a spare spark plug and spark plug wire. One end to the plug, the other directly to the ignition coil. Lay the spark plug on any metal body or engine component. have a buddy crank the engine while you watch the spark plug.

BowtieGirlZ28

I just had a similar thing happen to me and it ended up needing a new opti, the harness was melted!! I also had to replace the coil wire thingy...I hope you guys figure it out soon....

MasterTomos

iTrader: (15)

Im thinking the motor is going to get pulled sooner or later here. Probably replace the ICM and opti while we're doing the headgaskets.

96TransAmboosted

iTrader: (8)

http://www.arrowheadradiator.com/hea..._leak_test.htm

the link above is a tool we use at the shop to test head gaskets, works very well and is worth the money when owning these cars.

MasterTomos

iTrader: (15)

Back up top, I have a general question that pertains to this project.

When you blow a head gasket, obviously it can get exhaust in to the coolant, coolant in to the exhaust, oil into the coolant, and coolant in to the oil...

The motor has been sitting for a few months now and plugs have not been pulled. We drained the oil tonight and it came out at exactly 5 quarts, normal looking oil (not chocolate milk style)

Is there still a chance there is still coolant in the cylinders if there is no coolant in the oil that was in the oilpan?

Kind of a newbie question but I wasn't 100%

Thanks guys

96TransAmboosted

iTrader: (8)

Could be leaking into the cylinder itself, the head could be cracked or warped as well. You said it was smoking, but the oil is not molly and oil not in coolant. That tells me it might be leakig into the cylinder directly. Your going to need to diag more before anything. Have the heads checked

whytryz28

iTrader: (28)

Sounds like what happened to mine. Head gasket blew and was dumping my rad fluid into the cylinder, no change in oil level etc. etc.

Hook up a radiator pressure tester (rent them from vato zone)