Coolant leak on heads question

[chev-obsession]

So I bought a truck that sat in a field for the last 20 years, I went to go get it going and long story short I threw on a set of fresh 993 heads on. The engine is a bone stock 350, block has been surfaced at some point and I did not see any indication of a blown head gasket or cracked block when I cleaned the block. Heads were not killed but were checked for flatness and surface was cleaned, used permatex aviation form-a-gasket on bolts, Cleaned the deck very thoroughly with a razor blade, installed felpro blue head gaskets, torqued to spec in 3 steps.

Fired it up for the first time and I could see the head gasket was soaked and there was some coolant leaking onto the starter and a small puddle on the ground. I have never had to re torque the head bolts on a SBC after the first firing.

Any tips or tricks?

[crazy longhorn]

It sounds like you were very carefull on clean & check, just one more thought....could it be that the rear of the intake has a leak,& maybe following the back side of the head causing the drip on the starter? Just a thought....Longhorn

[Rickysnickers]

Yes, what did you use on the China walls, the gasket included in the had gasket set, or something like the Right Stuff? If you used a gasket, it could have squished out.

[crazy longhorn]

Originally Posted by Rickysnickers

Yes, what did you use on the China walls, the gasket included in the had gasket set, or something like the Right Stuff? If you used a gasket, it could have squished out.

Good call on the China walls....but it sounds like a coolant leak. My thoughts are that maybe with the block decked & or heads decked also, maybe the intake does not set all the way down (with the stock seals on the china walls)? This could cause a coolant tween the head & intake The best way to know, would be to pressurize the system (cold), & you will find the leak Many times , when blocks & heads are cut, the intake may also need cut to fit. Longhorn

[Dead Parrot]

Check the oil for signs of coolant and the coolant for signs of oil, just in case there is a problem with the block or head gasket.

2nd on checking the back bolts on the intake.

Check the freeze plugs. After a 20 year sit, they could be end of life.

[chev-obsession]

Originally Posted by crazy longhorn

It sounds like you were very carefull on clean & check, just one more thought....could it be that the rear of the intake has a leak,& maybe following the back side of the head causing the drip on the starter? Just a thought....Longhorn

I will have to check back there, I never thought of that, for some reason I went right to a leak on the heads.

Originally Posted by Rickysnickers

Yes, what did you use on the China walls, the gasket included in the had gasket set, or something like the Right Stuff? If you used a gasket, it could have squished out.

I used the little rubber gasket with the little tits to hold into the block, then used a very small dab on the ends of the rubber where the manifold gasket sits on top of them. Also used a very small amount of the right stuff around the water jackets on both sides of the gasket. I did not see any water in the oil but then again it was a very small leak.

Originally Posted by crazy longhorn

Good call on the China walls....but it sounds like a coolant leak. My thoughts are that maybe with the block decked & or heads decked also, maybe the intake does not set all the way down (with the stock seals on the china walls)? This could cause a coolant tween the head & intake The best way to know, would be to pressurize the system (cold), & you will find the leak Many times , when blocks & heads are cut, the intake may also need cut to fit. Longhorn

Thanks for the tip, I’ll have to figure a way out to pressurize that system to pin point the leak, I didn’t think about the deck height and how it would affect the manifold sealing.


Thanks for all of the replies. I will look in those areas

[RustyPile]

Originally Posted by chev-obsession

I will have to check back there, I never thought of that, for some reason I went right to a leak on the heads.



I used the little rubber gasket with the little tits to hold into the block, then used a very small dab on the ends of the rubber where the manifold gasket sits on top of them. Also used a very small amount of the right stuff around the water jackets on both sides of the gasket. I did not see any water in the oil but then again it was a very small leak.



Thanks for the tip, I’ll have to figure a way out to pressurize that system to pin point the leak, I didn’t think about the deck height and how it would affect the manifold sealing.


Thanks for all of the replies. I will look in those areas

You can buy a tester, but most automotive parts suppliers such as O'Reilly's have them for loan or rent. Here's a link to the pressure tester used to check a cooling system. https://www.amazon.com/Kauplus-Radia...911554&sr=8-10

[Rickysnickers]

Originally Posted by crazy longhorn

Good call on the China walls....but it sounds like a coolant leak. My thoughts are that maybe with the block decked & or heads decked also, maybe the intake does not set all the way down (with the stock seals on the china walls)? This could cause a coolant tween the head & intake The best way to know, would be to pressurize the system (cold), & you will find the leak Many times , when blocks & heads are cut, the intake may also need cut to fit. Longhorn

You are correct Longhorn. I wasn't fully awake when I posted that. Sounds kind of dumb now .

[crazy longhorn]

Originally Posted by Dead Parrot

Check the oil for signs of coolant and the coolant for signs of oil, just in case there is a problem with the block or head gasket.

2nd on checking the back bolts on the intake.

Check the freeze plugs. After a 20 year sit, they could be end of life.

Good thoughts....there is a core plug behind the starter. That would be an easy fix, if found there Longhorn

[crazy longhorn]

Originally Posted by Rickysnickers

You are correct Longhorn. I wasn't fully awake when I posted that. Sounds kind of dumb now .

I hate it when I dont have my coffee in the morning But you did bring up more fruit for thought.....you guys have to stretch is old mans memory Longhorn

[GASoline71]

Have the heads recently been magnafluxed? Could be cracked.

Gary