Coolant leak out exhaust manifold bolt #6

-
jwh70valiant

jwh70valiant

Well-Known Member
Joined
Aug 13, 2010
Messages
99
Reaction score
3
Location
Ohio
A mechanic told me that I have a cracked head, but I am not sure. My Valiant, slant six, has a small coolant leak out of the exhaust manifold bolt number 6. It usually just burns off, but if the car is parked up hill, quite a bit will drain out. I just went through flushing the cooling system, as there was stop leak in the system. It fixed the leak, but destroyed my thermostat, heatercore and caused the car to overheat! Terrible mistake!. So I flushed the system and put new anifreeze in the system.

I replaced all the seals a few months back when I broke two of the piston rods.

I read on another thread here, that the bold may be bad and I just need to coat it in permatex and reinstall. Should this fix the problem? There is no coolant in the oil and no oil in the coolant, so I know six month old headgasket should still be fine. Any Suggestions?
 
new stud and threadlock. that'll do the trick, just be careful taking the old one out, just sounds like a lil leak from a water jacket is all. no biggie
 
1970PAValiant is correct several of the studs go into water #6 being one of them. I use Loctite Brand Thread sealer. While you have the stud out check for erosion of the stud and replace as necessary. I also use brass nuts when I put any of the nuts back on as they wont rust in place.
Frank
 
I pulled the bolt out, the threading seemed good. I coated it with loc tite and reinstalled. I found, though, that it is tight but toward the end the bolt gets real loose gong in. So I left it out abit while it is still tight and let it dry. I started the car a little while later and after she got warm, steam came from the area, but didn't seem to come from the bolt. I am thinking that it might just be leftover spilt anitfreeze on the exhaust manifold.

Could it be something else now? I checked my coolant levels, and they are fine, so it dosen't seem to be leaking anything.
 
This might be a newbie question. I did that and it still has an occasional leak. It is not overheating, but is the car safe to drive with a small leak out of that bolt? I'm in the military and I am leaving in three weeks, so I will only be driving it for three weeks before its put in storage.

Thanks
 
Yes, it's safe to drive despite the minor leak. Keep an eye on the coolant level. Sounds as if the hole is wallered out (technical term). You will need to remove the manifolds to fix it properly. If you do not remove the manifolds, you will likely break off a drill bit and cause yourself much more grief (and work, and expense) than if you had removed the manifolds. You can get a stepped stud that's got bigger threads on one end and smaller on the other, Dorman #675-097. It has 3/8"-16 threads on the head side, and the stock 5/16"-24 threads on the manifold side. Overall length is a little shorter than the 675-092 standard replacement stud, but that's of no consequence. That's what I wound up successfully using at the end of a long comedy of ignorant errors and dumb mistakes (involving a hammer drill, "EZ-out", jigsaw, tap extractor, JB-Weld, Plexiglas heater, and assorted other inappropriate tools and supplies) a long time ago on my '65. All you have to do is overdrill the hole straight and true. Head on engine: Not a problem. Manifold on head: Not a chance.

Use Loctite (not RTV or teflon tape) on the head-side threads, which means you need to clean the coolant and tapping oil out of the overdrilled head hole using something (alcohol or brake cleaner, e.g.) that won't leave a residue. The head threads are 7/16" deep on the 675-097, while the original-type 675-092 has 9/16" of head threads; if you're careful and mark your tap accurately with a loop of masking tape, you can make (leave) a ledge at the "bottom" of the overdrilled head hole to bolster stud seating and sealing.

It is very much worth your while to get the good gaskets for the manifolds-to-head and intake-to-exhaust junctions.
 
You must log in or register to reply here.
-

Back
Top