Help Diagnosing Coolant in Head Runner
Thread Starter
Melting Slicks
Joined: Sep 2011
Posts: 3,372
Likes: 215
From: Peoria Arizona
Help Diagnosing Coolant in Head Runner
Hey all,
I have discovered that we are getting coolant into the #3 head runner. There is a small amount of coolant sitting on intake valve and coolant "rust" scaling in the head runner. Well, not really rust, but it's obviously from the coolant. All other runners look clean and dry.
Engine is a mild 350 with cast iron heads and Edelbrock Performer intake. I have replaced the intake gaskets once, and this did not solve the problem. Parked the car a few months ago after the gasket change to avoid damaging the engine.
Symptoms are:
Could you point me in the right direction on how to diagnose where the coolant is coming from? What should I look for that would indicate where the problem lies?
Thank you in advance for any help and please let me know if any other information would help you make suggestions.
Adam
I have discovered that we are getting coolant into the #3 head runner. There is a small amount of coolant sitting on intake valve and coolant "rust" scaling in the head runner. Well, not really rust, but it's obviously from the coolant. All other runners look clean and dry.
Engine is a mild 350 with cast iron heads and Edelbrock Performer intake. I have replaced the intake gaskets once, and this did not solve the problem. Parked the car a few months ago after the gasket change to avoid damaging the engine.
Symptoms are:
- As mentioned above - coolant in #3 head runner
- Small droplets of coolant found when I removed the valve cover. No white slime in the oil or oil in the coolant.
- slight bubbling in the radiator
- engine missing when started after running it up to temp (this clears up quickly - within 15 to 30 seconds)
Could you point me in the right direction on how to diagnose where the coolant is coming from? What should I look for that would indicate where the problem lies?
Thank you in advance for any help and please let me know if any other information would help you make suggestions.
Adam
Last edited by AdamMeh; Oct 3, 2015 at 11:17 PM.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Biggest concern is any water in the oil?
Water should be in only 3 locations:
-intake t-stat crossover > cracked intake/bad gaskets
-heads coolant passages > cracked head/blown gasket
-block coolant passages > cracked block
Something modern as far as tools go is a flex shaft camera. U can remove the plugs and look inside each cyl for signs of water residue. Remove the carb and look down each runner. Remove the dizzy and look under the intake also.
Choose your own plan here.
Water should be in only 3 locations:
-intake t-stat crossover > cracked intake/bad gaskets
-heads coolant passages > cracked head/blown gasket
-block coolant passages > cracked block
Something modern as far as tools go is a flex shaft camera. U can remove the plugs and look inside each cyl for signs of water residue. Remove the carb and look down each runner. Remove the dizzy and look under the intake also.
Choose your own plan here.
Thread Starter
Melting Slicks
Joined: Sep 2011
Posts: 3,372
Likes: 215
From: Peoria Arizona
I have the intake off and the coolant is in the runner, so I suspect it's coming from where the head and intake seal, but I'm not sure what to look for to figure out where the leak is at.
Race Director
Joined: Jul 2015
Posts: 13,082
Likes: 3,399
From: SW Florida.
it is very difficult NOT to get a lil bit if coolant in engine when pulling intake. you would hafta drain coolant, remove gooseneck and stick shop vac in gooseneck hole to not have any coolant drip in, and then you still could get a few drops. this is not a boat engine, but still check the bottom of manifold under coolant passage for rot-leakage long as it is off. i have thrown out every iron intake i ever pulled off raw water cooled 260 mercruiser engines.
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Thread Starter
Melting Slicks
Joined: Sep 2011
Posts: 3,372
Likes: 215
From: Peoria Arizona
Hi Derek,
Thanks for the response. Since we live in the desert, freezing isn't really an issue, so I'm thinking it's something to do with the intake gasket area then. When I pulled the intake, I was really careful not to damage the gasket so I could inspect it closely. Will head out to the garage and do that shortly.
If I can find a good straight edge, should I check the intake for warping? Although it would seem odd that just one cylinder would leak if the intake is the source. Is there something else that could cause just one cylinder to have coolant in the intake runner? The intake itself was clean and dry on that cylinder and all other cylinders runners are clean and dry.
I just read that checking the gaps around the intake could help diagnose the problem. Placing it on the motor without gaskets and use a feeler gauge to see if something is up with the overall fit of the intake to the heads.
Thanks again guys for the help with this.
Adam
Thanks for the response. Since we live in the desert, freezing isn't really an issue, so I'm thinking it's something to do with the intake gasket area then. When I pulled the intake, I was really careful not to damage the gasket so I could inspect it closely. Will head out to the garage and do that shortly.
If I can find a good straight edge, should I check the intake for warping? Although it would seem odd that just one cylinder would leak if the intake is the source. Is there something else that could cause just one cylinder to have coolant in the intake runner? The intake itself was clean and dry on that cylinder and all other cylinders runners are clean and dry.
I just read that checking the gaps around the intake could help diagnose the problem. Placing it on the motor without gaskets and use a feeler gauge to see if something is up with the overall fit of the intake to the heads.
Thanks again guys for the help with this.
Adam
Last edited by AdamMeh; Oct 4, 2015 at 12:11 PM.
Race Director
Joined: Jul 2015
Posts: 13,082
Likes: 3,399
From: SW Florida.
i think it was drippage when you removed the intake. any coolant in the intake passage would be sucked in when running and if there was much you would smell antifreeze in the exhaust. cuz there is really no coolant anywhere near intake runners. not in the manifold and can't leak into runners at the gasket. it would drip from the 4 end holes into lifter valley. the 2 china wall seals don't do much. you would get a little blow-by out there. the 8 intake runners if leaking would give a vacuum leak which would cause idle issues.
Thread Starter
Melting Slicks
Joined: Sep 2011
Posts: 3,372
Likes: 215
From: Peoria Arizona
I would say that it's possible it dripped in when removing the intake, but since there is no coolant passage by #3, there really is nowhere to drip from into that runner. Also, there is a scaling present in the #3 runner that shows coolant has been in that runner for some time. EDIT: One other thing - this is exactly what I found when I pulled the intake the first time and replaced the gaskets thinking that was the cause.
Personally, I think it's either an intake to head sealing issue, or (more likely) a crack in the head itself that somehow is allowing coolant to be drawn into the #3 runner. I also thought it might be a crack in the bowl area of #3 and coolant was being being forced up into the runner when the valve opens, but the coolant on top of the intake valve is bright green and very clean looking.
Thanks again!
Adam
Personally, I think it's either an intake to head sealing issue, or (more likely) a crack in the head itself that somehow is allowing coolant to be drawn into the #3 runner. I also thought it might be a crack in the bowl area of #3 and coolant was being being forced up into the runner when the valve opens, but the coolant on top of the intake valve is bright green and very clean looking.
Thanks again!
Adam
Last edited by AdamMeh; Oct 4, 2015 at 01:01 PM.
Thread Starter
Melting Slicks
Joined: Sep 2011
Posts: 3,372
Likes: 215
From: Peoria Arizona
Sorry for the delay in getting back on this. Had some sick people around the house.
After looking this over carefully, it's a leak from the intake gaskets, and due to this I suspect the intake is warped.
After looking this over carefully, it's a leak from the intake gaskets, and due to this I suspect the intake is warped.