Valve cover bolts backing out.

I changed my valve cover gasket last week (replaced with Felpro cork) on my '87 4.0L and tightened the valve cover to 55in-lbs per my Haynes manual.

I had driven it without issue until yesterday, when it let go and started spewing oil. I checked the bolts on the valve cover, and they weren't even finger tight. I've retorqued them, but I'm afraid that they'll work loose again.

Is this a common issue? What are the potential causes? My first thoughts were potentially a warped valve cover, stretched bolts, and possibly slightly worn or oversized threads in the head itself.

Should I look in to getting a new cover? If so, aside from a junk yard, where would I be able to find one? Would Loctite 242 (blue, medium strength) be OK to use? Is there anything I've overlooked?

RTV silicone. Works like a very mild thread locker and tends to get on the screws anyway when you use it as a valve cover gasket like me

Retorque them in sequence again, and if they back out, use some mild thread locker.

RTV Black, clear fingernail enamel, or LocTite 222 or 242 (nothing stronger than that!)

Just remove and reinstall the bolts, one at a time, with some mild "serviceable" loctite. read: NOT RED LOCTITE!

anyone know if those are torque to yield bolts. possibly try replacing bolts if that wasnt done the first time around.

99XJeeper said:

anyone know if those are torque to yield bolts. possibly try replacing bolts if that wasnt done the first time around.

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They're just regular bolts. The torque involved here is very small to begin with, which is part of the reason they loosen so readily.

99XJeeper said:

anyone know if those are torque to yield bolts. possibly try replacing bolts if that wasnt done the first time around.

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They are not. TTY screws are typically used for cylinder head screws (and main bearing cap screws, in limited applications - this is very atypical.)

As Mr. Currie said, the installation preload is very low - which is 1) why they cannot be TTY screws, and 2) why they tend to back out if you don't do anything to help them.

Upside? They can be replaced (if you like) using pretty much any 1/4"-20x1" or so screw, so you can use whatever you like. I do suggest you get small washers if you want to use socket heads - since the head is so small - but you can also use something like a pan head screw if you have a torque screwdriver. Or a flanged head, or ...

The bolts actually might not have moved at all....... some gaskets, especially cork gaskets compress after they have been heated..... they need to be retorqued.....

boojo35 said:

The bolts actually might not have moved at all....... some gaskets, especially cork gaskets compress after they have been heated..... they need to be retorqued.....

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Most "oil" gaskets - particularly cork - well tend to soak up oil, become saturated, and swell up when they've done so. That has a lot to do with why they have such low preload on the screws - because the gasket is supposed to take up just a little more.

That's why engines that have sat for a long time will tend to leak - because the gaskets have dried out and shrunk slightly. Even odd on whether they'll recover on their own, or whether you'll have to replace them outright...