What should I use to seal the pipe threads on my oil cooler when attaching the 1/2 inch npt fitting for the oil lines? Permatex high temp thread sealant? Any other suggestions?

Thread sealant works fine.

Or gasoila if you can still find it. It works great for that purpose as well.

We use Mercury Perfect Seal on all water and oil fittings. Easy to apply and clean up.

I have mercury perfect seal. I thought that was more for sealing gaskets?

OEM replacement sealer for OMC 508235, and MerCruiser 92-34227

· Used worldwide in the automotive, aircraft and marine industries

· Liquid sealant designed to meet rigid requirements of OEM specifications.

· Non-hardening and resists extreme temperatures.

· Seals all gaskets and threaded connections.

· Prevents corrosion of bolts, studs and fitting threads.

· Resistant to gasoline, oils, steam, salt-water, antifreeze and propane.

· Withstands temperatures from -50 F to 400 F.


Can be used on cylinder head gaskets, cap screws and studs, intake and exhaust manifolds, manifold gaskets, cylinder block and water pumps, oil pan gaskets, vacuum hoses, heat hose and radiator hose connections, welch plugs and water pump cap screws and studs.

We changed back to pipe sealant years ago instead of perfect seal on all pipe threads especially on the fuel side . The easiest way to clean up perfect seal or the other brands like aviation form a gasket sealant, peanut butter or whatever you use in that format is with Isopropyl alcohol. It cleans perfect seal off your hands or bilge compartment like it was never there. Reason for the change what does todays fuel contain plus a lot of fuel stabilizers & fuel additives contain ? A form of alcohol. J M O.

MerCruiser 92-34227

gasola or blue-block.both of these products are used in the plumbing/hvac trades.these products are for sealing pipe threads.