Intake Manifold O-Rings

[joefromsf]

Since I had my 93 GS500 torn apart to rejet and adjust valves, I basically kept going and have been removing pieces, checking conditions, cleaning and replacing as necessary.

So today I took off and inspected/cleaned the intake manifolds on the cylinder head. There is a set of o-rings between the manifolds and the cylinder head and I need to know how to tell if they are any good as the Clymer manual wasn't clear.

The manual said to check for cracks and there are no cracks, but I was wondering if these particular o-rings are suppose to be supple rubber like every other o-ring I've encountered or are they suppose to be a hard non-flexible material which is what I've found.

I can't tell if they were rubber that have just become hard over the years or if that was their original condition.  :dunno:  I've given them a gentle squeeze and there is no give. They really look and feel as though they were manufactured like that.

Anyone got any experience with intake manifold o-rings? Thanks.

[JamesG]

They should be harder than regular o-rings, but not plastic hard.  They are hi-temp rubber.

As long as they aren't cracked or permanantly flattened or distorted where they won't seal, they are good to go.

And if they are you can smear a layer of hi-temp RTV on it to fill the gaps.

[joefromsf]

They are as hard as plastic and are flat. Sounds like I ought to replace them while I've got them off.

Thanks.