I have a 1992 305 with too many miles on it. The person that had it before me kind of ruined it, so I'm trying to fix it. Every time the motor gets to its normal running temperature, the oil pressure goes to 0 unless I have my foot on the gas. I'm thinking maybe a oil pump? It definitely has oil in it, but the oil pump is probably the cheapest thing to do first, and it won't take me that long. Any ideas?

 

stop thinking oil pump and start thinking rod and main bearings...

too many miles + 0 oil pressure at idle but still having oil pressure while driving (although low) = worn out bearings.

You are at the stage now that if you do bearings you may salvage your crankshaft and connecting rods. They may be worn out of spec, but new bearings are certainly better than what you have now and if you save your crank and rods from making that annoying "knocking" sound then you may only have to have them machined a little when you finally tear down your engine.

Keep in mind that normal small block chevy oil pressure is 15 at an idle and 35 at 2500 rpm. Your oil pump is probably okay.

 

The oil pressure gauge sender is even cheaper, quicker, and more likely to be the problem.

 

The likely-hood of it being the oil pressure sender is very very slim!

rod and main bearings will go bad before an oil pump, but while you're changing the bearings you should go ahead and throw a new oil pump in there!

 

If the oil pressure was really 0, you'd know about it right away because the engine would be making all kinds of ugly noises.

 

Not true, my 305 ran for over a year with near zero on the gauge. Dyno Don replaced the sender when he did a custom exhaust for me, and now it reads 45 when cold and 30 at operating temp. It's a lot cheaper and easier tearing into the engine. If it really were 0 you’d know it by now.

 

The likelihood of a bad oil pressure sender is pretty high, actually.

 

Yeah, I will definitely try the oil pressure sender first, I have two other camaro's not running right now, so if it's the bearings, this thing is going to be sold. The person that had it before me took a hand saw and cut off the exhaust before the cat, and took the stock air cleaner off (along with the sensor) so it's obviously not running too great. I know there are lots of other problems, but the oil pressure is a different story. Thanks a lot.

 

So.....what was the cause of the low pressure ?

 

prob. the sender. I have seen this happen on so many lines of cars... this is sometimes how you can pick up good cheap eng.s

anyone with half a brain should screw in a mech. oil guage befor touching the internals

 

of course !
always the sender goes bad
i had this problem with my 82 bird but...it was bad old oil
a formula 89 was the sender ...
a turbo trans am 81 was the sender
and im having this problem now with a 87 vette
i will change oil+filter and we'll see !

 

My car does the same thing, but not quiet 0 like a couple milimeters befre it, but it runs great and it gets higher on the go, i think its just the sender.

 

Mine will go jump around 30 or a little lower when at a red light. But once I get going it jumps to 60.

 

Well, i have the same problem, thing is


I KNOW its something wrong internally due to the fact of grey metallic oil draining out

although heres a thought, my billet cam is eating away at the distributor gear.. and i ordered a bronze one... but wont come in till the 11th. I highly doubt all that color could have came from a dist. gear. But it is entirely possible