cracked a valve cover bolt hole. bad?

[ethangsmith]

I put a new valve cover gasket on the 88 Mustang (2.3L engine) and as I was tightening the last bolt down into the head (which is cast iron), the edge of the head split and a hairline crack formed. I drove the car around a few times today and nothing is coming out of it. It is an end bolt, at the back exhaust side of the head. It doesn't seem to be in any immediate danger of hitting any internal fluid passages. Does the hairline crack matter or is there an easy fix for it?

[Chris Wood]

if it leaked, I'd put some epoxy on it.

[ethangsmith]

It does not seem to be leaking at all at this point. It just kind of confuses me as to why it cracked. I wasn't even putting much muscle into it at all. Hopefully it will be ok.

[richpet]

Those take very little torque. A little epoxy, and maybe a dab of silicone and all should be dandy.

[82mustang]

i bet there was old silicone in the hole, and when you threaded in the bolt it hydrolocked the hole in the head causing a crack, all that pressure had to go somewhere..is the cracked head aluminum or steel? i honestly wouldent worry much about it unless a leak develops, and clean that hole out while you're at it

[fred414141]

if and when it needs attention,i'd clean the threaded hole and epoxy a stud in there. use a washer and nut when the cover goes back on.

[ethangsmith]

The head is cast iron. I haven't had any leakage out of the hole and I have run it about an hour and a half now. I did smear a little non-hardening gasket sealer over the crack area and I can't find any leakage, so it's good so far. I have an extra head for the car so I am going to send that out to a machine shop and have it rebuilt in case the head on the car decided to give me trouble.

[ujslost]

I dont think your going to have any problems with this. But not a bad idea to have that spare head ready to go to work when the time comes

[Zap's 85 GT]

One of my two spare 2.3t heads looks to have had a repair to one of the valve cover bolts. Seemingly from a similar issue as yours. I'm guessing this is not an isolated incident.

[ethangsmith]

Yea, I've heard these heads have issues with cracking around the valve cover bolt holes but I have never heard if it is an issue or not. So far no leakage.