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how tough are o-rings?

Behind my oil pump cover, there are two o-rings, one that seals the crank, and one that seals the tensioner bolt hole, and the rest is sealed with RTV. In torching the tensioner bolt (and pulley...) in a previous attempt to get the bolt off, a lot of smoke was produced. I hope it was just the pulley seals and/or any crap that was on the block. What I'm wondering is if the o-ring around the bolt hole on the other side of the cover is likely to have been affected, and is this something that is worth pulling the oil pump to check out? I was thinking that I could turn the motor by hand or crank the starter to see if it leaks, but I don't think that gives me nearly enough oil pressure to be a realistic test.

Also I'd like to know if I should put anything on the timing tensioner bolt threads like thread locker. The old bolt (which I had to grind off in the end) was not seized into the block bore, but it was torqued down *way* too hard, and I wonder if that was because they were trying to keep it from working its way out over time - something that blue threadlock could accomplish with less headache down the road.

Reply to
Ryan Underwood
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You should change the o-rings if you heated them that much. You should use a torque wrench to install the new bolts if you feel you need to have them potentially under torqued, and you should use loctite, personally I would use blue or red. It's entirely possible that this application uses a high strength bolt that is torqued fairly high to prevent it from coming undone, which would be rather catastrophic. It can take a lot more torque to undo a bolt than to install it even if it isn't over torqued on installation.

Brain

Reply to
Brian

Not tough enough to take torch heat. I would change them and use the loctite.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Ryan Underwood wrote:

Reply to
Mike Romain

The shop manual calls for 31 lbs on the tensioner bolt which isn't all that much. That's why I figured it should have something on the threads to keep it in place. How difficult is it to break loose red loctite?

Reply to
Ryan Underwood

I would normally use red loctite for something that I did NOT want to come undone, and with a fastener size of 5/16" or greater, what ever that is in Metric. If you have a torque spec of 31 ft-lbs, then red is OK. You can kill the red loctite by heating the bolt head dull red and letting the heat soak into the threads. Blue loctite I use when I have a smallish fastener (5/16" or less) that I will be taking out cold. But proper torque stretches and pre-loads the bolt such that it will not come undone anyway, short of failure. I carry blue loctite, but I really don't use it much. If I think I really need it, then I usually find another way to accomplish the task. On the other hand, blue loctite is great on motorcycles with high vibration when the bolts often aren't really torqued but only stuck into aluminium, etc. I usually safety wire that sort of thing, but that wouldn't look good on a showy bike.

Brian

Brian

Reply to
Brian

If the heat didn't get it the 190k miles on it did. O-rings are cheap. Go get new ones. (and a new pulley as well instead of a junk yard pull)

If you torque the proper bolt to the proper specs it should not come loose but putting a little threadlock on there won't hurt anything and will stop you from worrying about it which is worth the price of admission.

Steve B.

Reply to
Steve B.

Since the tensioner mounting bolt is a 10mm bolt, it is just smaller than

5/16. But if minor heating (as opposed to torching) will undo the loctite, then I'll go ahead and use it on the tensioner bolt. I doubt I'll have to do another timing belt for the life of the car anyway. (Mark those words...)

Luckily, it appears there was no o-ring around the tensioner bolt hole where I thought there was one (after consulting the photo of the BACK of the oil pump cover in the teardown manual). It appears that the o-rings seal the oil passages and are in diagonally opposing corners across from the tensioner bolt hole. So unless we managed to do something bad to the RTV that seals the pump cover, I think I should be okay here. Good thing too, because I don't think I would be able to remove the crank timing gear. I tried prying it off with two big screwdrivers like the book says without a budge, and there is no room for a puller in there.

Reply to
Ryan Underwood

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