i just recently bought a 90 IROC with 123,xxx miles and it blows white smoke out of the tailpipes when i get on the gas and when it's started up. i understand this is from burning coolant but my question is how could i know how bad this really is? could it just be a cracked head gasket...or a cracked head? this a 350 TPI L98 motor btw, it's slightly modded with new runners and throttle body. so ANY help at all as to what the problems could be and how to fix them is greatly appreciated. i've only done amatuer type work so having to rebuild this is going to be tough so thanks for any help you can lend

 

Start pulling spark plugs.

When you find the one thats soaking wet in antifreeze then you know where the problem is at.

Then you can start tearing into it. pull the head and inspect the headgasket for damage, then the head and cylinder for any cracks.

 

thanks. have you ever dealt with this sort of thing? any estimated time, cost and how much of a pita it is? i'd also really appreciate step by steps for head removal though it seems pretty cut and dry. basically just dont want anything to go wrong that can.

 

I'm proud that you're willing to work on your own car 8)

Cost? <$50 DIY, $600 for a shop to do it.


Disconnect battery cable
Pull belt(s) off
Drain engine coolant
Remove accessories (on that head's side)
Disconnect all wires and connectors
Disconnect fuel lines and coolant lines
Remove the plenum and intake, including linkages and distributor
Check for ground straps on the back of the head, remove if necessary
Remove the exhaust manifold
Remove rocker arms and pushrods
Unbolt the 17 head bolts
pull the head off (might need a prybar)
replace head gasket and inspect head for obvious cracks
good time to clean up the carbon deposits in the combustion chambers


when reinstalling rockers, be sure to set valve lash (search)
change oil and top off coolant
suggested to replace O2 sensor, as burning coolant kills them


It's easier than it looks. It's just a pain in the ***. Don't be afraid to do it yourself, there's pretty much nothing you can "break" or mess up. You could finish it in a day even as a novice. Just keep your bolts in order, remember to reconnect all the wires, and keep things clean.

 

thanks so much for the help. i'm a 17 (almost 18) year old kid that uses this car as his daily driver. i had a ton of problems with my last car (88 RS), did a bunch of neccessary body work on it then lost the whole thing in a fire...so it seems like i've been having tough luck with my cars, so any help is greatly appreciated.

 

i just did heads and intake on my 305 , never done it before , all i did was mark where the vac , fuel , and other wires go and started tearing it down , once you get one side off it get easy , just remeber to put it together how u took it apart,
if you have to do head gaskets , clean the old gasket off before installing the new one

 

Before I ripped apart the top half of the motor I would start with just replacing the intake gaskets first. I also recently purchased an 85 TA and the 383 crate motor had only 25k on it but the guy I bought it from used the wrong kind of sealant on the intake gasket causing it to leak. You can also do a compression test on the cylinder with the coolant on the spark plug to determine if it has a cracked head or bad head gasket. If you have a compressor or acess to one you can use the same hose from the compression tester to inject air into the cylinder. Make sure that the radiator cap is off when you perform all tests for some times it will bubble when tests are performed. Good luck

 

Sounds like a good excuse to buy a new set of heads. Or at least get them both worked on. Personally, If I was going to remove one head, I'd do them both at the same time. By the time you take one head off, most of the work is already done.

 

good call, my bad

 

alright finally got the time to start tearin into her. i've pulled half the plugs so far and none have been wet, just a little charred so i'm replacing them with Delco rapid fires. my question is, is it possible that when my new throttle body was put on by the previous owner that they didnt use any sealant or the right sealant on the gasket and thats why its burning coolant? i've got a feeling thats it becuase the night before i started taking her apart i ran against a 94 LT1 Z-28 and took him pretty easily so i dont think its a cracked head cause i'm still making real good power. what do you experts think?

 

come on, i'm sure someone can simply tell me whether or not it could be the TB gaskets

 

Wow, havent seen this thread around in a while...

I dont have much experience with TPI setups but it cant be a TB gasket can it?

Doesnt the coolant just circulate through the TB and back out, without going to the plenum?...


One possibility is the intake gaskets, they can sometimes leak and dump A/F into a runner or the lifter valley.



Anyways check all the plugs. It only takes 1!

My previous motor popped a head gasket and would flood only #6 with water. It also ran decent, not great but it still had some power...