no oil pressure after oil change/oil pan repair

Bob & Tracey · March 30, 2020, 04:53:59 AM

I changed the oil and filter on our 8V71 in a 4104 and after refilling I noticed a leak at the drain plug. I removed the pan and repaired a bad repair on the drain plug insert. The pan was off the bus several days while waiting for a gasket. Pan reinstalled and oil filled to the full mark I started the engine and had no oil pressure. Turns out on the refill I was two gallons of short of full (another story), oil level returned to the full mark and still no oil pressure.

Any thoughts?

muldoonman · March 30, 2020, 05:08:00 AM

If you had pressure before,, Gauge faulty?

Bob & Tracey · March 30, 2020, 05:10:45 AM

Muldoonman,

I am going to explore that today.

buswarrior · March 30, 2020, 07:34:18 AM

loosen off a handy oil fitting, the sender/gauge place is as good as any.

see if you get some oil out of it while running?

quickly, of course...

Don't you just hate it when you make new ones, trying to fix old ones?

happy coaching!
buswarrior

Bob & Tracey · March 30, 2020, 10:08:42 AM

I definitely have 0 oil pressure! Now what?

richard5933 · March 30, 2020, 10:49:45 AM

Assuming your oil pump didn't crap out, almost sounds like something like your pickup tube came loose or somehow is sucking air instead of oil.

When you had the pan down, did you notice anything fishy with the pickup?

Or, is there any chance something got on the bottom of the pickup which is blocking it?

luvrbus · March 30, 2020, 11:18:05 AM

Pull the pan and look for a shop rag or towel and make sure you have 6 gals of oil sometimes the pump will air lock and you overfill the pan till it picks oil up then drain the excess oil

chessie4905 · March 30, 2020, 11:18:14 AM

Sounds like you lost prime from sitting so long draining. In cars, you could pack the oil pump gears with vaseline. Especially done on early Buick V6's.

chessie4905 · March 30, 2020, 11:22:03 AM

For quick help, give Luke a call. Mention that it drained for a couple of days with pan off. Is there a way to prefill the oil filter? Does it have a plug in the metal housing?

Bob & Tracey · March 30, 2020, 11:49:37 AM

Richard, can the pick-up tube come loose that easy? I did bump it a couple times getting the pan in place.

Luvrbus, I am sure there are no rags in the pan. How much oil should I add? Seven gal in it now.

Chessie, Luke suggests removing a valve cover to hold rack in no fuel and crank until oil shows up in the line to oil pressure sender. Funny thing I was working in a Buick garage when they brought back the V6 and yes we had to prime the pump the same way. Lucky it was easy to get to.

Bob & Tracey · March 30, 2020, 02:00:41 PM

I used a variation of Luke's suggestion, I held the governor in no fuel and after 30sec of cranking oil started to flow!

Thank you guys for your help!

Bob & Tracey · March 30, 2020, 02:04:56 PM

Don't know why or how to fix the photo...

richard5933 · March 30, 2020, 04:02:43 PM

Quote from: Bob & Tracey on March 30, 2020, 02:00:41 PM
I used a variation of Luke's suggestion, I held the governor in no fuel and after 30sec of cranking oil started to flow!

Thank you guys for your help!

Glad you got it going.

To answer your question about the pick up tube, I've read about various things going wrong with them, including hairline cracks. Wouldn't take much to make a defect in the metal into a leak capable of sucking air. Doesn't sound like that's your problem though if you got it pumping.

Scott & Heather · April 02, 2020, 09:29:08 PM

This is why you own one of these:

Bob & Tracey · April 04, 2020, 05:21:06 AM

That would have been nice!