So a couple of weeks ago i took my 95 firehawk out for a test run after installing lowering springs and tunnel mount adjustable torque arm. everything went smoothly but about 4 blocks from my house i was sitting at a stoplight and noticed that some steam came from the right corner of the hood. got the car home and opened the hood to see quite a bit of steam coming from the area near the rear of the cylinder head. my first thought was that it was the steam pipe seals. thought it would be a simple fix. found the seals online and ordered them from summit racing. after getting the seals in the mail i removed the steam pipe (with intake and strut brace still in car). used my gasket cleaner attachment on my die grinder to clean all the gasket surfaces and even sprayed carb cleaner on a rag and reached back to clean everything as good as possible. keep in mind that the old seals had areas of light visible around the edge where the rubber and metal meet. I then added some teflon tape to the threads of the bolts and pre-installed them to the steam pipe and bolted everything back up. topped off the coolant and started the car up. seemed fine at first but once the cooling system built a little pressure the leak started again. very frustrated i pulled everything out again and even swapped steam pipes with an extra from my spare engine. same issue! it is hard to see back there since all i am using is a mirror and a surefire flashlight but it appears that the coolant is comeing from between the head and block. is this a common issue with LT1's? Has anyone had problems resealing the steam pipe? I am open to suggestions as it takes me a mere 5 minutes to pull everything out now that i am well versed at it.... and and all help will be greatly appreciated. oh, and btw, no there are no signs of coolant getting into the #8 cylinder. nothing on the plug and not smoke out the exhaust.... THANKS in advance for help.

Karl

 

There aren't too many possibilities for coolant leaks back there. Either somehow the steam pipe fittings aren't sealing or it BHG'd.

My first guess would be that you mauled the head with the die grinder so it isn't flat anymore. Banjo bolts shouldn't have teflon on the threads either. Maybe that is keeping the bolts from tightening completely. That is all I have got.

 

well i didn't use a die grinder so to speak, just a right angle type pneumatic die grinder with the gasket cleaner attachment on it and never once touched the cylinder head with it. merely cleaned the steam pipe gasket surfaces. also i first installed the banjo bolts without teflon tape and they leaked horribly bad so tried it using teflon tape to see if that was the problem.

 

Did you get new bolts? Either there is corrosion on the surfaces or the head gasket is leaking,you said coolant appears to be coming from between the head and block?

 

It is very hard to tell since the angles that I have to hold the light and mirror at to see it is so bright the coolant looks pretty much clear. I can see where it has been on the block, but not much at all where it would be coming form the banjo bolts. Also no I did get new banjo bolts as I would have no idea where to get them. I did clean the threads and bolts with a wire wheel on my grinder to really clean them up. I am at a loss and do not want to pull a cylinder head and find nothing wrong with the gasket and go through all that time and money for nothing.

 

try using copper gaskets with a touch of rtv on both sides of the copper ring?, maybe find a proper size rubber o ring and hope for the best.

 

well i am using the factory GM part #10108689 coolant pipe seals so i dont see any reason why they shouldnt be sealing. seems to me like the factory original part would be far superior to any "O" ring or copper seal.....

 

eh, sometimes you get lucky. if the factory stuff isnt working, then you need to try a different avenue to rule out a gacked head gasket

 

Is everyone here retarded? Telling him a million different ways to seal the steam pipe when thats NOT THE PROBLEM ....?

I have two words for you man.

Head
Gasket

Do a pressure test to verify...

 

it is indeed the head gasket.... capped everything off and used my air compressor to put about 20psi of air into the system and the started blowing coolant out the back of the head. there was so much it made it easy to find! ripped it apart and found that the the upper rear coolant jacket port that goes between the block and the head it what was leaking. the felt on the felpro gasket rotted away and allowed the coolant to leak out. on a good note i have been able to verify some parts that were intalled on my car by MTI (the one out of houston) such as crane gold roller rockers, comp beehive springs, what appears to be stainless retainers and some trickflow push rods. also found that it has ARP head bolts. arent these re-usable as long as i use moly lube when i torque them down? thinking about swapping out cams while im this far into it.... it has the LT4 hotcam right now. any recommendations? It is a stock bottom end but soon will be going 383 or 396 so would prefer a cam that i could re-use maybe.....

 

Glad you found the issue.

 

For anyone else who is going to do that test don't use more pressure then the system is rated for. The system is rated for 18psi You should use some sort of blow off valve to make sure you don't pop the heater core. I don't see a problem with 20 but it's getting close. Just a reference. Other wise you all are going to be replacing unnecessary parts and gaskets lol.

 

That is a very good point! Believe me, I was very careful! Did not really think to point that out to the general population though.

Right now I am debating whether or not to install a new cam and get rid of my LT4 hotcam and/or send my heads to AI for their CNC 200 job. Have seen some really impressive numbers with these heads on everything from stock short blocks to fully built 383's with power adders. Any suggestions?

 

Can't go wrong with a stock casting AI or LE head worked out like that. Have them find a cam for what you want and it's money well spent. You will spend the next round of dough on traction lol.

 

I have no doubt that traction would be the issue as it has been for the many years ive owned the car. On a lighter note everything behind the engine has been beefed really well. did some suspension stuff shortly after buying the car and then grew from there into a Strange S60 with 4.10's, chromemoly DS, and later a Rockland Standard Gear "son of tranzilla" T56, McLeod twin disc with billet steel flywheel, Tick master cylinder, and Quick time Inc. bell housing with a mini starter. At the time i did the trans and clutch i upgraded to kooks long tubes and Mufflex 4" catback as well. A better set of heads with a larger cam would make this thing nasty until i build an all forged short block....

 

For about 4000 bucks to AI and with a stock bottom end will hit over 400rwhp.

 

well ive already made over 350rwhp with a bad knock sensor pulling 8* of retard and when i calculate my 1/4 times against the weight of the car with me in it it lands around the 410 to 415rwhp mark so if it would take $4k to AI to do that then ill pass however, i doubt the cost would be that high. their CNC 200cc head job is 1750 and for another 395 can get one of their custom cam grinds and with another 295 a set of patriot gold valve springs and then its just the cost of gaskets and putting it back together and some tuning. Don't see me hitting the $4k mark on that.... just my input though.

 

I think he was actually right on but that includes everything. That is what they quoted me several years ago for a set of trickflows worked with cam and complete valve train from lifters to rockers.