Blown head gasket?
Thread Starter
Drifting
Joined: Jul 2022
Posts: 1,359
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From: Wisconsin
2024 C3 of the Year Finalist- Modified
2023 C3 of the Year Finalist - Modified
2022 C3 of the Year Finalist - Modified
Blown head gasket?
So my dad and I rebuilt my motor and unbeknownst to me my dad installed the head bolts on the mk iv block without thread sealer. It hasn't overheated but it didn't take long for bubbles to appear in the expansion tank and the rad was gurgling. Now my coolant looks oily.... I checked the dip stick and it's the tell tale milkshake....my oil pressure is also unstable, kinda jumping around it used to stay between 65-70 psi depending on rom. Now itll get pretty low. My dad's convinced it still wasn't the lack of sealer on the head bolts and still swears he never used any back in the old days. What say you fellow c3ers?
Melting Slicks
Joined: Apr 2021
Posts: 2,710
Likes: 2,156
From: Minnesota
Yes, you should use thread sealer on the head bolts. They go into the coolant passages. I use a combination of teflon tape and a thread sealing paste for extra insurance.
I’m surprised your dad hasn’t had any issues doing it in the past, maybe he’s just been getting lucky.
You might be able to change out your head bolts one at a time, adding sealer to the threads then re torquing to spec. Afterwards a thorough flush of the coolant passages and a couple oil changes.
Or the right way of tearing everything apart and cleaning it, ect
I’m surprised your dad hasn’t had any issues doing it in the past, maybe he’s just been getting lucky.
You might be able to change out your head bolts one at a time, adding sealer to the threads then re torquing to spec. Afterwards a thorough flush of the coolant passages and a couple oil changes.
Or the right way of tearing everything apart and cleaning it, ect
Thread Starter
Drifting
Joined: Jul 2022
Posts: 1,359
Likes: 822
From: Wisconsin
2024 C3 of the Year Finalist- Modified
2023 C3 of the Year Finalist - Modified
2022 C3 of the Year Finalist - Modified
Yes, you should use thread sealer on the head bolts. They go into the coolant passages. I use a combination of teflon tape and a thread sealing paste for extra insurance.
I’m surprised your dad hasn’t had any issues doing it in the past, maybe he’s just been getting lucky.
You might be able to change out your head bolts one at a time, adding sealer to the threads then re torquing to spec. Afterwards a thorough flush of the coolant passages and a couple oil changes.
Or the right way of tearing everything apart and cleaning it, ect
I’m surprised your dad hasn’t had any issues doing it in the past, maybe he’s just been getting lucky.
You might be able to change out your head bolts one at a time, adding sealer to the threads then re torquing to spec. Afterwards a thorough flush of the coolant passages and a couple oil changes.
Or the right way of tearing everything apart and cleaning it, ect
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Head bolts, like those from ARP demand use of a lube for proper torque of the bolt.
Does that lube also seal the threads? H-m-m-m-m-
The head bolts enter the blocks water-jacket. For oil to seep onto the head bolts it would have to come from under the valve cover area, around the rockers.
What's the odds of that? Pretty good odds on the end bolts that commonly sit in a pool of oil.
However, there is another possibility about your milkshake issue, and that is the Intake gasket breached. There are water ports on the ends of the Intake gasket that keep coolant from entering the lifter valley. H- m-m-m-m-m-m-m
Bubbles in the Rad? Only sure proof is a exhaust fume seeker / testing tool installed in the Rad.
Does that lube also seal the threads? H-m-m-m-m-
The head bolts enter the blocks water-jacket. For oil to seep onto the head bolts it would have to come from under the valve cover area, around the rockers.
What's the odds of that? Pretty good odds on the end bolts that commonly sit in a pool of oil.
However, there is another possibility about your milkshake issue, and that is the Intake gasket breached. There are water ports on the ends of the Intake gasket that keep coolant from entering the lifter valley. H- m-m-m-m-m-m-m
Bubbles in the Rad? Only sure proof is a exhaust fume seeker / testing tool installed in the Rad.
Thread Starter
Drifting
Joined: Jul 2022
Posts: 1,359
Likes: 822
From: Wisconsin
2024 C3 of the Year Finalist- Modified
2023 C3 of the Year Finalist - Modified
2022 C3 of the Year Finalist - Modified
Head bolts, like those from ARP demand use of a lube for proper torque of the bolt.
Does that lube also seal the threads? H-m-m-m-m-
The head bolts enter the blocks water-jacket. For oil to seep onto the head bolts it would have to come from under the valve cover area, around the rockers.
What's the odds of that? Pretty good odds on the end bolts that commonly sit in a pool of oil.
However, there is another possibility about your milkshake issue, and that is the Intake gasket breached. There are water ports on the ends of the Intake gasket that keep coolant from entering the lifter valley. H- m-m-m-m-m-m-m
Bubbles in the Rad? Only sure proof is a exhaust fume seeker / testing tool installed in the Rad.
Does that lube also seal the threads? H-m-m-m-m-
The head bolts enter the blocks water-jacket. For oil to seep onto the head bolts it would have to come from under the valve cover area, around the rockers.
What's the odds of that? Pretty good odds on the end bolts that commonly sit in a pool of oil.
However, there is another possibility about your milkshake issue, and that is the Intake gasket breached. There are water ports on the ends of the Intake gasket that keep coolant from entering the lifter valley. H- m-m-m-m-m-m-m
Bubbles in the Rad? Only sure proof is a exhaust fume seeker / testing tool installed in the Rad.
Le Mans Master
Joined: Mar 2004
Posts: 7,493
Likes: 1,502
From: Little Rock AR
A brush can of Permatex "Hi Tack" on the clean bolt threads has never failed me. I chase the bolt threads first and paint them any time before assembly. No rush at all, it gets sticky but you can do it the day before if desired.
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Thread Starter
Drifting
Joined: Jul 2022
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From: Wisconsin
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Melting Slicks
Joined: Dec 2009
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From: Thunder Bay
The potential for disaster is too great to fool around. Pull the heads and change the gaskets. Hope that the water in the oil hasn’t taken out the bearings. You’ll know once you get it back together. If you have decent oil pressure you’re good.
Safety Car
Joined: May 2001
Posts: 4,757
Likes: 1,647
From: Fairfax Virginia
I totally agree with drwet!
You should replace the head gaskets after the engine runs for any time at all. I would then do the best and most through cleaning that has ever been done before rebuilding the engine. This is a good lesson so lets not make it an expensive one. BB head gaskets are not cheap, I was really perplexed at the various choices when I was shopping for Mark IV head gaskets Being from a BB they will show the "BB tax" in the form of double the SB price.
You should replace the head gaskets after the engine runs for any time at all. I would then do the best and most through cleaning that has ever been done before rebuilding the engine. This is a good lesson so lets not make it an expensive one. BB head gaskets are not cheap, I was really perplexed at the various choices when I was shopping for Mark IV head gaskets Being from a BB they will show the "BB tax" in the form of double the SB price.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Let's not jump to conclusions.
Diagnose first.
Then throw parts & $$$$$ at it.
I think I would introduce compressed air into each & every sparkplug hole first, while watching the upper radiator for bubbles with cap off.
Of course, the piston must be at TDC firing stroke.
Diagnose first.
Then throw parts & $$$$$ at it.
I think I would introduce compressed air into each & every sparkplug hole first, while watching the upper radiator for bubbles with cap off.
Of course, the piston must be at TDC firing stroke.
Last edited by HeadsU.P.; Aug 4, 2024 at 04:39 PM.
Cruising
Joined: Sep 2021
Posts: 11
Likes: 3
From: Springfield, VA
Some of the other responses on this thread said the same thing I'm going to say. YES!! if the bolt holes go into the water jacket, you do need the thread sealer and not just a little bit but a LOT. I used thread sealer on studs for my SBC and they leaked. (with thread sealer) I talked to two different chevy mechanics and they both told me to gob it on. So I did and now, NO leaks. I had to pull the heads and clean the holes first though. PTA
Thread Starter
Drifting
Joined: Jul 2022
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From: Wisconsin
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Thank you for the replies, guys. That tool should show up tomorrow. I'll get out to the garage and do a pressure test too and that combustion test.
Le Mans Master
Joined: May 2007
Posts: 5,025
Likes: 1,120
From: North tonawanda NY
They work well! I used one myself to check my car and found my issue to be something else entirely but it was a smoking issue and not gurgling rad at the time. If you have water in your oil I wouldnt even risk running it long enough to use this.
Thread Starter
Drifting
Joined: Jul 2022
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From: Wisconsin
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What were you appearancing?