Ok motor's bin in the car for 4 weeks now. Up until the last 2 days the oil pressure has been fine. 20-65 psi consistanly from my melling High Volume. 2 days ago I'm sitting at a light in gear and the pressure drops like a rock to 0. So I figure no biggie I change the oil. now the pressure drops if I it still and put it in N or P. I've got 5W30 now but I'm getting ready to put in 20W50 and a new OP sending unit. Am I stupid for trying this or should I pull the motor and get a new pump/pick-up tube. I'm going nuts and I'm about ready to just let the motor kill itself.

Chris

 

Don't put 20W-50 in a new motor. That would be a big mistake.

Put a new sending unit in it before you get all excited about it. Remember, a motor with zero oil pressure will let you know in no uncertain terms that it's unhappy, long before it will just blow up; it will make all kinds of noise, especially valve train noise, from teh lifters having no oil. If the motor sounds the same, idle speed hsan't changed etc., then odds are very good you don't have a pressure problem, just a metering problem.

 

Another thing, check your oil on the dipstick for any signs of "glitter." It's possible some material from any number of things might have broken off...or whatever... and a few peices of shrapnel may have found it's way into the oil pump and knicked the impellers. Goofy chevies don't filter the oil at an idle, unless you weld the by-pass shut. This happened to my friends Malibu at the track, he'd have all kinds of pressure then all at once nothing. Thought it was the gauge, so we hookes up a different one to check, same thing. Got home-he shut it down after the gauge swap, pulled the pan, pump and tore the pump apart and sure enough there were just enough knicks/scratches that would make it act goofy. First thing next morning got a new pump, bolted everything together, took 'er aroung the block to check it, everything checked out and we still made it to the track for the second days race where he finished a cruddy 4th after all that rig-a-mor-role.

 

ok best part is the motor is broken in. I drive a whole lot, so I already put the 20w50 in. She actually likes it better than the 5w30. I also bought a sending unit. It's gonna go in the next few days. I haven't noticed anything different about the engine. No idle change and no abnormal noises. I even shut everything inside off and stood by the motor and nothing sounded different. I'm pretty sure the unit is bad. It just amazes me that it was a "good one minute, bad the next" deal. It litterally happened that fast. (I monitor guages constantly because of doing all the work myself) Once I change the unit I'll let you guys know if I'm pulling the engine next week. Thanks for the advice.

Chris

 

So, did the new sender work out for you, or what?

 

whoa old post. i guess it did or the car is long gone by now...