2001 Monte Carlo SS
V6 3800
Fuel Regulator went bad caused plenum to blow up and start fire.
Went to repair and thought I would replace intake gasket and lifters while it was apart.
Fixed everything and ran great for a few days now RED low oil pressure light comes on in message center and gauge drops to zero.
It does come back up to normal oil pressure.
But never had this problem before.
I'm going to put a manual gauge on it to check it.
Any ideas????
Thanks David

 

I wouldn't worry much until you confirm with a mechanical gauge that it's real, although I'd also stop driving it until you confirm.

Complete loss of pressure on a 3800 isnt common given the way our oil system is set up.

 

Well I put a manual gauge on it, and it is losing oil pressure.
Back to square one.
Going to change filter, hopefully it's bad.
but I doubt it.
Any ideas ???
Thanks !!

 

Would need more info about what you're seeing as it's not clear from the first post.

You say it goes to zero, but also comes up to normal. When does each occur / what changes between the two conditions?

Has it ever had an issue at all, or just after the intake explosion/ lifter replacement?

 

Loss of oil pressure
when you start car up oil pressure is good drive it around seems fine drops to about 40 lb under load when you get on it and push it oil pressure drops to about 20 and doesn't recover very quickly sometimes not at all then shut the car off let it sit and it goes back to normal intake gasket and lifters were replaced never had the problem before the plenum blow up going to do an oil change and try another filter. Currently have manual gauge plugged in still. On occasion it starts to tap like valve train issue I'm guessing because lack of oil I don't let it run much when that happens thanks for your input

 

Yes, I have heard of similar issues caused by a bad filter. Try another filter and see if that helps. Uncommon but not unheard of.

 

Yikes, hopefully you've quit driving it until this is sorted out? Could definitely destroy the engine if not careful.

Oil pressure likely starts decent as it's cold and naturally higher pressure. Certainly a cheap trial to switch filters.

The tapping is likely from the lifters collapsing due to not enough oil getting to them to stay pumped up.

How soon after the lifter swap did the issue start?

 

Well It seems the oil filter housing was clogged !!
Took it off cleaned it out and cleaned block.
Good oil pressure now and no low oil pressure lights.
Back on the road !!!

 

Thanks for the follow-up. Always good to know what fixed an issue. I have heard of this before but it is rare. Normally, the loss of oil-pressure is terminal.