Please help! Coolant leak from exhaust stud (and one other thing)

Hi guys,

Really needing the knowledge of the community for this one here.

I just finished assembling my rebuild and took the Lancer out for a test drive. It runs great, but I discovered a problem.


Here's a link to a google album with picture/videos of the issue: https://photos.app.goo.gl/r5D7oL4LD3oTSrgM9


I have coolant leaking out of the exhaust stud just under the intake bolt shown in the image.

Now when I had the head done, I replaced the factory studs with a brand new set from FWDP. I do remember that a couple of the studs (including this one) were pretty stuck, but I was able to back them out without any signs of damage to the threads.

All the studs were installed according to the factory service manual, finger tight with high-temp thread sealant, then the nuts were torqued to spec.

This leak was very minor to start, but was causing plumes of vapor to rise when it would hit the exhaust manifold.

When I found the issue, I thought to check to make sure it hadn't loosened up somehow. I got a socket on there and gave it just a tiny tweak, maybe turned a 1/16 rotation, if that. It was still snug, but as soon at it moved the leak became worse and started dripping down (before I could be under the thing and wouldn't get dripped on at all, barely anything leaked without the engine running).

I'm not sure what to do at this point...I fear that I'll have to pull the head, but I literally just got this thing back together and really don't want to have to go through all that if I don't have to. Am I missing something here? Why would the coolant be leaking past the stud if it was installed with high-temp thread sealant and installed according to the service manual?

Is there anything I can do in this case? I'm not sure how I would back the stud out with the head on the engine, I can't even see it from under the car and had to go by feel just to get a ratchet on it.

SECOND QUESTION

So far I've put 20 miles on the thing, driving WOT through the RPM range at about 4psi (manifold source directly routed to wastegate) and letting the engine compression decel me back to seat the rings. The car ran great, and was eager to go - man, I was smiling ear to ear to be back behind the wheel of my baby.

However, I went to change the oil and was shocked to see it a muddy brown color! (video of oil draining in the google album) This oil only had 20 miles on it. But here's my suspicion.

The oil still felt/smelled like oil. No gas smell that I could tell, I didn't see any separation in it like it was getting mixed with coolant. I installed ARP head studs for this build and the studs/nuts still had a good amount of their special black lubricant on them. I'm thinking (and praying) that the coloration is only due to the hot oil dissolving the black lubricant into the oil. I'm hoping somebody can confirm this, but I suppose it's cheap insurance to just change the oil after another 20 miles and see what it looks like.

First, I gotta fix this coolant leak cause that just won't stand.

Are you certain you hit all of the studs and bolts with thread sealer?

I would think the oil is just colored from the lube, but it should be easy to check and see with the cheapest Pharos store oil they have.

I always tighten the studs down to end of thread on stud using jamb nuts. Then let the thread lock dry thoroughly before tightening the jet nut. If I feel any stud move, I start over. I do this to avoid what you're experiencing. I hope you can remove the stud without removing the cylinder head. You could even try some red 271 or green sleeve Loctite on the nut to try to get the stud to remove with the nut. At this point, can't hurt right? I used to use some old Saturn exhaust manifold studs because they had Torks socket ends on them, so no need to use jamb nuts. These are getting harder to find now.
What did you use for assembly lube for main and rod bearings? Anything like white Lubriplate 105 assembly lube will discolor your engine oil.
Here is an attachment or two of all the areas that intersect oil and coolant on the back of the cylinder head. Black circles = coolant, red circles = oil passage (not oil pressure). Blue circle = oil pressure. Red circles can cause oil weeping/wicking problem, as they intersect other holes where oil can be present.
Todd

Quote:

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Originally Posted by cordes

Are you certain you hit all of the studs and bolts with thread sealer?

I would think the oil is just colored from the lube, but it should be easy to check and see with the cheapest Pharos store oil they have.

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Oh absolutely, I used permatex high-temp thread sealant on every stud. I'm positive I didn't miss any. I didn't put any on the threads for the nuts, though. Didn't think it necessary there as there was no need to "seal" anything.

Quote:

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Originally Posted by 4 l-bodies

I always tighten the studs down to end of thread on stud using jamb nuts. Then let the thread lock dry thoroughly before tightening the jet nut. If I feel any stud move, I start over. I do this to avoid what you're experiencing. I hope you can remove the stud without removing the cylinder head. You could even try some red 271 or green sleeve Loctite on the nut to try to get the stud to remove with the nut. At this point, can't hurt right? I used to use some old Saturn exhaust manifold studs because they had Torks socket ends on them, so no need to use jamb nuts. These are getting harder to find now.
What did you use for assembly lube for main and rod bearings? Anything like white Lubriplate 105 assembly lube will discolor your engine oil.
Here is an attachment or two of all the areas that intersect oil and coolant on the back of the cylinder head. Back and blue circles = coolant, red circles = oil passage (not oil pressure). Red circles can cause oil weeping/wicking problem, as they intersect other holes where oil can be present.
Todd

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Those images are useful, thanks. I knew some of the studs extended into water and oil passages, but didn't know exactly which ones and where.

Man, this situation is a huge bummer..I thought I was being so careful and following the 'official procedure' for things. I'll have to take a more careful look at things when I have a chance to get out to the shop again, cause I have a sneaking suspicion that one of the studs near the starter is leaking a bit too. I've put some UV dye in the coolant and will poke around with a blacklight when I get the chance.

I reeeally don't want to have to pull the head, but I have this sneaking suspicion that it's the only way to correctly fix this.

Is there a sealant you prefer over permatex high-temp thread sealant? I really don't want to have ANY more issues related to these dang studs..

if you end up pulling the head I have a suggestion for thread sealant

but your threads have to be clean and oil free..

use white plumber's pipe dope.. it should never leak and probably won't come apart again without drilling the stud out..

if it's good enough for the hot water radiator in grandma's living room it will work on your exhaust studs

though (cough) you DON't wanna use it on the big fitting for the heater hose under the T-stat..or anything you might need to disassemble

Dorman 03411B if your on a budget. Or ARP 400-8014 if your not. Both work for 2.2 exhaust studs and they have an end feature to assist in removal and installation in tight areas.

Thanks for your input so far guys, I really appreciate it.

Had a thought for doing the job without pulling the head. I used a new manifold gasket of course for this job, and it's only had a couple heat cycles on it.

Think it'd be possible to pull the intake manifold so I can reseal the exhaust studs one/two at a time, then reinstall the intake and reuse the gasket? Just spitballing here, I've only had this one TD and haven't had to do anything like this before 😅

Also, has anyone used those Dorman studs before? Be a shame to not use the ones from Cindy, but I do like the idea of having something to get ahold of on those things in the future.

As far as pipe dope goes...if it's as strong as you say, I'm a little hesitant to use it. This head was beautifully worked on and I'd hate to 'weld' any hardware in there lol.

I use a plumbers stick which looks like a crayon. I get it at my local hardware store. It’s rated for fuel and I’ve never had a leak if I do my part. I use it on everything from coolant to fuel and anything in between. It’s not rated for natural gas and that’s the only thing I don’t use it on.

Quote:

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Originally Posted by cordes

I use a plumbers stick which looks like a crayon. I get it at my local hardware store. It’s rated for fuel and I’ve never had a leak if I do my part. I use it on everything from coolant to fuel and anything in between. It’s not rated for natural gas and that’s the only thing I don’t use it on.

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Huh, I would have never thought of that. What made you decide to try it one day?

Quote:

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Originally Posted by Mudman

Huh, I would have never thought of that. What made you decide to try it one day?

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I live in a small town and needed something on the spot. At the time it was more than an hour round trip to the nearest parts store. I just used what the local hardware store had on hand. It worked really well an the sticks are less than two bucks I think. I use it exclusively now.

Just wanted to give an update. I was able to pull the main offending stud, clean and dry everything, and reinstall with silicone. That one no longer leaks!!



I still have some VERY slow coolant seepage from at least one other stud, but I mean we're talking sloww. For now, the car is drivable and I can really dig into breaking it in.



When nicer weather rolls around I'll likely pull the head and redo all the studs properly. Until then, I'll just keep an eye on my coolant overflow tank level and enjoy the ride 👍

Good to hear you got it fixed! And to let you know this post helped me out! We were in the middle of changing the turbo on my sons Daytona and I had totally forgot about the whole leaking stud thing. We sealed ours up and let it sit inside (very cold in Ohio) for a few days to make sure everything cured. So far it is back together and running with no leakes.

Hey man if I can learn from my mistakes why shouldn't others? Lol

I'm glad to hear your assembly went well!! Cheers to having our TM's on the road again 🍻

"a man learns from his mistakes while a wise man learns also from the mistakes of others"