[69 redbird]

I have a 69 FB w/ 350 eng. 4bbl carb. a edlebrock pontiac performance intake manifold.
It's been leaking anti-freeze from the intake right above the waterpump. I decided i was going to tackle, changing the intake man. gasket.. Well, i just picked it up (felpro- MS9980) These are 2 gaskets? that look like they go one on each side of the manifold. The leak is in the front of the intake. Am i supposed to put RTV or something across that area?
I guess i was thinking it would have been some kind of valley pan gasket??? well i guess you can tell i haven't done a JOB like this before.....

Thanks for any advice on how to do this job...

[AGTO8U]

There is round rubber type seal that goes in between the intake and the water pump housing. You can use RTV on that and around the water crossover openings to help prevent leaks. When you get the intake in place, start all 10 bolts in the manifold, then tighten the bolt that goes from the water pump to the intake FIRST, followed by the other 10 bolts. Avoid excess RTV as it could sqeeze into the water passage and restrict flow.

[BVR421]

find out exactly where its leaking from before you take it apart, from reading your post it sounds like you arent sure yet

[69 redbird]

I took a couple of pics. I hope y'all can see them. The antifreeze is sitting in that valley section? I just can't see where it's coming from?

[69 redbird]

How can i test to figure out where this leak is coming from?

[petesake]

You can get a pressure tester. It replaced the radiator cap and you pump it like a bicycle pump. If you see antifreeze leaking from that area then it is definately the "o" ring in the front of the manifold. As someone else mentioned, start the intake bolts then tighten the long bolt. This will move the manifold forward.

[66Mutt]

The coolant appears to be pooling on the valley tin ABOVE the gasket surface of the tin and intake manifold. That would lead me to believe that you have a leak in the round rubber seal between the intake and the water pump. You might see if the bolt that snugs the water pump up to the intake manifold (located to the right of the round gasket) can be snugged up. But it is likely that the seal has hardened. My engine had the same leak and it seemed to leak more when the engine was cooling back down.

You might get by with just buying the water pump gasket set which includes the rubber seal. If you replace the intake manifold gasket, you may need to pull the water pump and replace its gaskets too just to make sure everything gets aligned and torqued properly.
Doug

[69 redbird]

I will try to test it first, to see where it's coming from. Thanks guy's...

[dmorg1]

I had the same pooling problem on my LeMans. The pooling only occured after shutdown, no leaks while running. Check around the thermostat housing for some telltale signs of wash. I replaced the thermostat housing gasket and pooling stopped. Much easier fix than manifold gaskets, if that's the cause.

Dave

[steve]

when you pull the manifold tight against the timing cover do no torque the whole way down until you have some light torque on the other manifold bolts......... tighten the bolt that goes from the water pump to manifold snug, then do the sequence on the other manifold bolts like halfway, then torque the water pump to timing cover bolt all the way, then go back and do the other manifold bolts the rest of the way. re-check the bolts after a few hundred miles. makes sure all surfaces are super clean with mineral spirits or something like that first, anti freeze has a way of keeping your "permatex ultra grey" from sealing if there is residue. JMO.

[69 redbird]

Thanks a lot

[shineybike]

I'll second the post regarding the thermostat housing. I had leakage just as you described and it was coming from the T-stat housing. I replaced the gasket (which was new) and used some RTV, but it still leaked. Re-did it but first used some sand paper or emery cloth to make sure the surfaces were smooth. Worked the second time and no problems since.

[77birdman]

That long bolt on the right hand side of the water pump needs to be tightened, same thing happened to me. It is the bolt going thru the pump housing, in my 1977 it even have a small triangle type of washer going with it.

[69 redbird]

I will be checking this leak out real good before i go changing anything....

[69Customs]

I had the same problem but took the easy way out, added a can of stop leak and it fixed the problem. But if your really set on finding the leak the pressure pump test is the way to go, you will either see antifreeze coming out where its leaking or hear air hissing. I bought a radiator pressure tester years ago (Stant) and it is one of the best tools for checking cooling sytems.