Hi guys,

I have a 1988 trans am gta with the 350 TPI. I have owned it for four months and it has always had a slight coolant leak. I have maybe added two three pints of coolant during the 300 miles or so I have driven it

There is not really signs of any leaks apart from some tiny puddles on the passenger side of the intake manifold. Do you think this is the intake manifold gasket that is leaking or could it be something else? Car otherwise run fine and doesn't overheat. And no sign of water in the oil or white smoke from the exhaust.

Thanks!
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Picture below of the manifold.

 

Could be a head gasket or an intake gasket leaking into an intake port. Such a small amount of loss would be tough to track down.

 

Sounds like you already know what's wrong and don't want to face up to it. Which I can't blame you for that, fixing it is not very pleasant. However, the only way for it to get ON TOP OF the intake, is via the bolts; butt the only way for it to get THERE, is a failed intake gasket. So, after car-washing all that schmutz off of your intake that you can see in the pic, it looks like your upcoming weekend is all planned out for you.

Head gaskets rarely leak coolant invisibly, without other FAR MORE SERIOUS consequences. Coolant passages there can leak coolant only 3 ways: into the crankcase, in which case (no pun intended) you'd see your oil turning into grayish powdery gloppy gook; into cylinders (combustion), which the leak going the opposite way (combustion into the coolant) would be obvious; or externally, such as down the side of the block. In NO CASE can they possibly put coolant on top of the manifold. I'd save those for the VERY LAST suspect.

Far more likely, after the problem you already know you have, would be: the head bolts, specifically the row under the exhaust ports (the other 10 would leak into the crankcase and produce the above described coolant-in-the-oil symptom); the water pump (vent hole for the bearings weeping, which the coolant ends up on the inside of the pulley and gets slung everywhere as a fine mist); the heater core or radiator, butt you'd probably smell it, or worse, if it was the HC, or see/smell it from the radiator; or the coolant recovery bottle (cracked).

Get up under the front of the car and look up at the bottom of the lower rad hose. If there's signs of a drip running down the bottom of it, you need a water pump.

Intake gaskets almost never leak from coolant to ports. There's like 4 times as much gasket that it would have to go through horizontally to get there, than to get to the outside world. By the time one gets bad enough to leak into the ports there'd be coolant dripping EVERYWHERE. Kinda like, what you've got.

Based on the concept in my signature, I'd start by quarter-car-washing the motor after soaking it for a bit in spray-can engine degreaser (NOT the "foaming" kind) so that all old dried-up grungy crustified leakage from prior centuries is cleaned up. Then I'd fix the problem(s) I ALREADY KNOW OF, namely intake gaskets, which will be far less unpleasant when you don't have to wallow in the 10,000 years of funk all over everything. Put some thread sealer (NOT RTV) on the 2 center bolts on each side, and wire-brush the bolts real good and run a thread chaser down the 2 bolt holes at each coolant port, and use anti-seize on those. Then, if new intake gaskets didn't completely cure it, and when I could actually see what I'm doing, I'd inspect the radiator and cap and bottom of the coolant bottle, then if all that is OK look at the WP.

Save head gaskets for after doing all that. Save alien abduction, and their clandestine consumption of your particular car's coolant as a powerful aphrodisiac intoxicant, for even later.

 

@sofakingdom Huuge thanks for this and for the weekend plans, lol. I needed to hear this. I actually allready have the intake gasket set from Fel Pro waiting on the shelf.

The car is my project car so I'll see when I get the time to fix it, two small kids at home so time is a luxury. But I will return and tell you how it goes.

 

Pull the heads & see if u can locate anarea where the gasket has failed. At this point, u could choose to have the heads planed especially if u have a lot of miles on the engine.
I replaced the head gaskets on my 1972 Buick GS 350 once & when leak appear 8 year later, I had the heads planed & rebuilt.
Before u reinstall heads, be sure all surfaces are super cleaned then reinstall with new ARP head bolts, which I did. I also used a thread chaser to clean the threads before installing the head bolts.
Goo luck

 

Did you verify the hose that comes out of the throttle bottle area is not leaking, that leak appears to be in the general area. lots of hoses in that area in fact. I'd pressurize the cooling system and look for leaks. easiest way to find it.

 

"tiny puddles on the passenger side of the intake manifold"

Where you see coolant, there is a leak!!!



Thats a pretty big job though unfortunately.

 

It's not the heads or head gaskets. Head gaskets can't leak up on top of the intake manifold.

Don't worry about head gaskets or pay any attention to anyone who talks about them.

Blue's idea about the hoses is worth checking out though. I kind of assumed you had already looked at those and not found a problem. Butt we all know what happens when you break the word "assume" down into its 3 basic component parts...

 

Allright, so we are finally half way there. Just got it all torned apart. Not that bad of a job, just time consuming. Especially since this is my first time.
I wonder if the gaskets have ever been off the car, man were they nasty looking and brittle stuff. It also had the rubber gaskets for the china walls which seem to have been leaking as well.

Anyways, I noticed that the coolant passages were quite brown/rusty looking, especially in the rear. Anything to be concerned about?

 

The factory didn't use rubber gaskets on the china wall so someone has been in there before.
i have to do one of my cars soon as well, not looking forward to that

 

No, just put it back together.

 

Job done! Finally got it reassembled. Hardest part were getting the distributor back in the right place. Otherwise it wasn't a bad job. Just took ages to clean off all the old rotten gaskets.

Had it idling in the driveway a long time to burb the cooling system and everything seems to work well, no wet intake anymore nor leaks from the front china walls.

Seems to be idling better as well, I also replaced a rotten vaccum hose along the way.

Huge thanks to everyone for their help, I will return here if there still are any leaks.

I actually had a lot of white smoke when I first started it up so immediately started suspecting head gaskets, but it all disappeared when the engine warmed up.



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