Blown head gasket, cracked head,,or bad oil pump

Well, I have been trying to figure out why my automatic Turbo TC's oil pressure gauge has been reading low and when I rev it it drops to zero. I replace the IVR and no change. I replaced the ignition switch and no change. So then I attached a mechanical oil pressure gauge and it reads 20psi and then when i rev it ,it drops to zero and stay there at zero

I have no water and oil mix on dipstick, BUT I did "possibly see' freon drip out of the rear exhaust manifold bolt. I first thought it was coming from the heater core line but it seems to be coming out of the manifold bolt.

Could a cracked head show low oil pressure? Could a a blown head gasket show low oil pressure? Do I just need to call it a day and pull engine?

I think it's time to pull the head. Or maybe as a check, pull the dizzy and spin the oil pump with a drill to double check.

By the way, why are you putting freon in your radiator? :dunno: tickpoke: :giggle:

it could be any of those things, except i would rule out the oil pump because of the anti freeze issue. it could also be a cracked block. as mentioned, pull the head and have it checked out.

I've never tried spinning the oil pump with a drill. How is that done? Do I have to add some kind of attachment to the drill?

i use the center shaft of an old distributor chucked up in a drill.

i use the center shaft of an old distributor chucked up in a drill.

What he said^^^