Topic: Cooling System Leak - 1969 w. Flow Kooler
in Forum: C3 Cooling and Heating Systems
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O.K. - here is a list of what I have done so far - had the radiator re-cored; flushed the block and refilled with water / glycol; Replaced the hoses, thermostst, and thermostst housing.
The water pump blew out last fall, and after a long search, including Bill Mock, I could not find a numbers matching water pump. The engine is a small block 350/300 with factory A/C. It runs great, although with the headers, the cabin gets extremely warm - year round.
After much pondering I decided to install a Flow Kooler water pump to improve the cooling of the engine. It supposedly pumps 30 to 40% more volume than a standard water pump. I had to put on a reinforced lower radiator hose so it wouldn't collapse.
Everything has been running great, but now I see a small amount of cooling fluid at the front of the block above the number 1 cylinder. Most of it was on the intake maniflod - an Edelbrock Performer, and a small amount on the block. After drying it completely and runing the enging until it warmed up, It appears to be seeping from under the intake manifold.
BIG QUESTION - is this just a poor seal of the manifold gasket at this point or is it going to blow the gasket out entirely? It does not spray, it just slowly seeps through.
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I'd say looks like somebody is goin to be pulling the intake off.
If it's leaking to the outside, chances are it's also leaking to the inside.
Best thing to do would be go ahead and replace the intake gaskets. Be sure to NOT use the rubber end seals that fit across the front and rear of the block. They can keep the intake from setting down properly, which can lead to weird leaks like this. Use black sillycone on the block ends.
Of course, the intake could also be corroded around the water jackets, causing the leak.
The new water pump may have simply accelerated the leak...it would have shown up eventually anyway.
If you do replace the gaskets, use a small amount of Permatex "Aviation Sealer" around the water jackets(only!) of the gaskets. Let it sit for a few minutes before you put the gaskets on the heads. This will ensure no leakage from around the gaskets there.
If it's leaking to the outside, chances are it's also leaking to the inside.
Best thing to do would be go ahead and replace the intake gaskets. Be sure to NOT use the rubber end seals that fit across the front and rear of the block. They can keep the intake from setting down properly, which can lead to weird leaks like this. Use black sillycone on the block ends.
Of course, the intake could also be corroded around the water jackets, causing the leak.
The new water pump may have simply accelerated the leak...it would have shown up eventually anyway.
If you do replace the gaskets, use a small amount of Permatex "Aviation Sealer" around the water jackets(only!) of the gaskets. Let it sit for a few minutes before you put the gaskets on the heads. This will ensure no leakage from around the gaskets there.
Joel Adams
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I agree with everything Joel said. When I installed my Performer I used the rubber gasket in front and back and it didn't set right. So I put a nice round bead of silicone front and back and it did the trick. Also I think its important to tighten the bolts in the right sequence and torque. Joel prolly knows what the torque setting is.
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#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
Intake bolts are 35lbs/ft, if my memory is still semi-intact. Start in the center and work your way out criss-cross. Be careful tightening the end bolts around the water jackets...do them slowly. 
Joel Adams
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Joel:
So if it IS leaking to the inside, wouldn't I notice something - like the engine running crappy or something like that?
I'm supposed to be attending a cruise-in weekend starting this Friday - about an 80 mile drive one-way. What are the chances I'll have a catastrophic failure on the road!!!
When the water pump blew I sat on the side of the road for 3 hours waiting for AAA to pick me up (it was way out in the country)!
How difficult would you rate this gasket replacement job???
Jim
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Jim, would wouldn't necessarily notice any difference in they way it runs...it's a small leak, from what I gather, and it is around the coolant passage(s), not around the actual intake passages.
The only thing you would notice, IF it is leaking to the inside, is possible milky oil when you pull the dipstick, or the filler cap. It would have to be leaking internally quite a bit to mix in with the oil and do that, so if your oil looks normal, you're prolly okay.
Have you checked the bolts to see if they are loose around that area? You may be able to snug them up a little and stop, or ar least slow down the seepage. I'd suggest checking them anyway, just in case.
Changing the intake gaskets is not all that hard, or technical. It's simply a matter of remove/replace. Of course, if/when you decide to tackle the job, we're right here if you run into any issues, and need help.
The only thing you would notice, IF it is leaking to the inside, is possible milky oil when you pull the dipstick, or the filler cap. It would have to be leaking internally quite a bit to mix in with the oil and do that, so if your oil looks normal, you're prolly okay.
Have you checked the bolts to see if they are loose around that area? You may be able to snug them up a little and stop, or ar least slow down the seepage. I'd suggest checking them anyway, just in case.
Changing the intake gaskets is not all that hard, or technical. It's simply a matter of remove/replace.
Of course, if/when you decide to tackle the job, we're right here if you run into any issues, and need help.Joel Adams
C3VR Lifetime Member #56
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You will need to pull the distributor to pull the intake. So mark the distributor housing to the intake, and the position of the dist rotor before you pull it out. Then dont turn the engine, and put the dist back in place matching your marks. That will be close enought to start the engine and do the fine tuning with a timing light. With care, you may be dead on.
all good advise. should you decide to go original. i have my original `69 350/300hp a/c water pump. seemed to be working fine when i pulled it off the car. Bob
Thanks to all for the advice/support!
I have pulled the distributor before, so I am familiar with that process - and last time it was "dead on"!
I did try to snug the manifold bolts, but they wouldn't budge, so I suspect its just a problem with the gasket or sealer at the point that it is seeping water.
I haven't checked the oil, but will take a look just out of curiosity.
Too bad I didn't catch this last fall so I could've done this over the winter!
Jim
in Forum: C3 Cooling and Heating Systems
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