Head gasket leaking

chicklin · Post by **chicklin** » Sat Feb 11, 2012 5:43 pm

Well, after getting the rest of the engine tuned up I took her for a spin this afternoon. She started, ran, accelerated and idled great. Get her back to the garage to knock the idle down just a hair and noticed I am now the proud owner of at least two separate head gasket leaks on the outside of the block. Who knows what it looks like inside, although I have good compression and don't think there's any coolant in the exhaust.

Gasket set on the way. So, other than following the TM, what tips do you guys have for doing this job? I assume everything needs to be cleaned really well. How do I know if the head needs surfaced or not? Is replacing the studs normal or only if they look bad?

Post by **Ryan_Miller** » Sat Feb 11, 2012 8:48 pm

IF you replace any head studs use permatex #1 on the threads as they communicate with the water jacket.

After proper tightening sequence of the head stud nuts, warm up the engine and then retorque. If you don't, then your head gasket will leak.

chicklin · Post by **chicklin** » Sat Feb 11, 2012 10:57 pm

Okay, I'm dumb. This is an F-head. Looks like it's all cap-head screws instead of studs and nuts, right? Will still put permatex on them, but hopefully that makes things easier.

Post by **wesk** » Sat Feb 11, 2012 11:40 pm

The F134's can be found with and without studs. I prefer studs because they go in once and stay there thus the threads in the block do not get as worn.

You can determine the flatness of both the head and the block deck with a quality straight edge and a flash light. Use the light to see under the edge of the straight edge as you move it slowly across both surfaces. If light makes it under the straight edge then sealing the head will not be possible until the surface is machined flat.

Do not overlook the real short bolt inside the intake manifold under the carb. You must remove the carb to access the small bolt.

chicklin · Post by **chicklin** » Sun Feb 12, 2012 8:57 am

Mine appears to be bolts, not studs. I assume they are nothing oddball, so if any of them look iffy, I'll replace them all.

I bought Fel-Pro composite gaskets. Do you know if those are the re-torque style or not? I'll check the package to see if it says, but I don't look forward to having to tear the top of the motor apart a second time just to re-torque the bolts.

danrothe2001 · Post by **danrothe2001** » Sun Feb 12, 2012 12:08 pm

They are sold as no retorque, but they should be. However, you do not have to tear the motor back apart. Torque the head bolts by the book. Then let the motor sit for at least an hour, preferably overnight. Then go through the torque sequence one at a time and loosen each head bolt and pull it back to full torque value in one pull. Do not loosen them all at once, do them one at a time. The engine does not have to be warmed up, it just needs to sit with the gaskets torqued so they take a set. This info came from a Fel-Pro engineer and I have been using it on 14 to 1 Chevys for 20 years with no problems. The gasket should come with a blue side and a silver side. The blue side goes towards the head and uses no sealer. The silver side goes to the block and uses sealer. My favorite is spray on Copper Kote, although I am sure that there are other good ones available.

Dan

chicklin · Post by **chicklin** » Sun Feb 12, 2012 3:01 pm

Good info, thanks.

artificer · Post by **artificer** » Tue Feb 14, 2012 2:18 pm

Doesn't matter whether bolts or studs [& I, like Wes, would always prefer studs] you should always use thread sealer & if you didin't that is possibly your problem.
Drain coolant & remove 1 bolt @ a time apply sealant to the thread & replace until all are done. Then retourqe the lot in correct sequence before starting run 30 minutes or more the redo.
I would not be removing or replacing the head gasket until I tried this & it did not work.
You do not indicate anything regarding internal leak, which should be obvious.
Australian older mechanics use/used spray can silver frost paint on replacement head gaskets.

chicklin · Post by **chicklin** » Tue Feb 14, 2012 7:09 pm

I haven't done anything with it as this is a new-to-me jeep. So, I don't know whether thread sealer was used or not.

The two leaks are right at the seam between the head and the block. And, now that you mention it, they are each directly underneath a head bolt. Both on the passenger side, one at the far back nearest the firewall, one one the front just below the oil filter bracket.

At this point, there is no evidence of internal leaking. If I'm going to pull the valve cover and carb to remove/replace every bolt, though, I might as well pull the head while I'm at it, right? I've got the gasket on hand and would then have the peace of mind knowing it's been replaced.