Oil Pan Flange - domed bolt holes

[Peter S.]

This oil pan, as well as every other gasketed surface, leaked like a sieve before teardown. As I prep it for installation, I noticed that the bolt holes are heavily domed from the bolts being torqued down. I can flatten them somewhat going around with regular tip C-clamp. Is this worth the risk? Any other method to flatten out the bolt holes?

[Joe L.]

Re: Oil Pan Flange - domed bolt holes

This oil pan, as well as every other gasketed surface, leaked like a sieve before teardown. As I prep it for installation, I noticed that the bolt holes are heavily domed from the bolts being torqued down. I can flatten them somewhat going around with regular tip C-clamp. Is this worth the risk? Any other method to flatten out the bolt holes?

Peter------



You must flatten them. I usually do it by placing a block of hardwood under the holes and tapping them flat with a hammer.

[Peter S.]

Re: Oil Pan Flange - domed bolt holes

A block of wood - I feel a little silly for not thinking of that. Thanks Joe.

[Leif A.]

Re: Oil Pan Flange - domed bolt holes

And, then when rebolting, be aware of how tight you bolt up. I usually put all bolts in finger tight and then starting in the middle and working my way out, I tighten until snug and then and additional 1/4 turn.

[Peter S.]

Re: Oil Pan Flange - domed bolt holes

And, then when rebolting, be aware of how tight you bolt up. I usually put all bolts in finger tight and then starting in the middle and working my way out, I tighten until snug and then and additional 1/4 turn.

[Domenic T.]

Re: Oil Pan Flange - domed bolt holes

Peter,
When tightening as said above, they will loosen as the gasket takes a set. I always do a retighten a few times until the stabilize.
Most shops/dealerships don't have time to do it that way and only tighten once. Also if using a sealant it is easy to split the gasket at each bolt.
I usually let the sealant set up before final torque. Everyone has their way of doing it but as Joe said tap each down, best done with the whole side of the pan on the flat surface.

Dom

[Joe L.]

Re: Oil Pan Flange - domed bolt holes

Peter,
When tightening as said above, they will loosen as the gasket takes a set. I always do a retighten a few times until the stabilize.
Most shops/dealerships don't have time to do it that way and only tighten once. Also if using a sealant it is easy to split the gasket at each bolt.
I usually let the sealant set up before final torque. Everyone has their way of doing it but as Joe said tap each down, best done with the whole side of the pan on the flat surface.

Dom

Dom-------


This is another advantage of using the one piece gasket. Each of the bolt holes is fitted with a compression-limiting "ferrule". So, the gasket is compressed by the exact amount required and the amount of torque applied to the bolts is limited. With this type gasket, no re-torque is required.

[Steve G.]

Re: Oil Pan Flange - domed bolt holes

When I first started working in the trade I wondered why the original OE gaskets stuck like glue to the both sides (on anything, valve covers, water pumps...)with no traces of glue and the joint completely sweat free while gaskets that had been replaced once peeled off the surfaces with ease when torn apart and, if not leaking profusely, at least had a good sweat at the joint. In fact the OE gaskets on the valve covers stuck so tight you would bend the lip of the valve cover trying to pry them off.

The reason turned out to be an oil free surface. Not just wiped down with a rag soaked in solvent or gasoline (always a bad idea) then dried off with a dry cloth, which was what was usually done in the trade. This left behind traces amounts of solvent or oil which inhibited the gasket's ability to seal.

It's gotten much easier to get a dry joint with the availability of aerosol brake cleaners. These work remarkably well at lifting the contaminants from the surface. It works best if you actually spray the surface rather than wiping down with a rag saturated in the cleaner. The spray seems to lift stuff out of the "pores". Blow dry with air and keep your oily fingers off of the surfaces.

Steve

[Patrick H.]

Re: Oil Pan Flange - domed bolt holes

Peter------



You must flatten them. I usually do it by placing a block of hardwood under the holes and tapping them flat with a hammer.

Agree. I use a ball peen hammer which works very well.

[Domenic T.]

Re: Oil Pan Flange - domed bolt holes

Joe,
I guess I have to move up to the modern tech.

Dom