I need to change the oil pressure sending units on my 496 HOs. I'm getting inconsistant readings from the guages and I've narrowed it down to this. These are the bell looking type behind the block. When i pull the old ones am i going to have an oil mess going on? I just want to be prepared. Is teflon ok to use on the threads or should these be dry installed? Thanks

Very unusual that both would go bad or act up at the same time unless maybe you had salt water corrosion or issues at the back of both engines. I would suspect grounds being the issue with two oil pressure readouts on two engines acting up at the same time. In any event, with the engines off you will not spill a drop of oil changing them. I would recommend just a small smear of thread sealant like permatex, versus teflon. Most oils ,especially synthetics don't get along well with teflon sealants.

Best Regards,
Ray @ Raylar

I'm sorry, I should have explained myself better. They both didn't go bad. I was getting different readings on my guages so I started by having the guages checked and they turned out fine. Then I checked the engines with a mechanical guage and all was good. At this point I only have one sending unit that seems to be sticking at a certain psi when at idle or on the throttle. That's why i decided to just change them both while I was doing it. Are these a common thing that gets replaced on the 496 motors? The engines only have about 160 hours.

I personally have not seen or experienced any real amount of failures in these analog guage sending units, but I know there must be some failures as "there are no perfect parts!"

Best Regards,
Ray @ Raylar