Oil Pump Shot?

[yembo77]

OK guys. Everyone has been screwed in their lives, including me.

 

So please chime in here and tell me if you think I'm getting the shaft from a mechanics mistake.

 

I've driven 5 chevys to 200K miles!

 

I have NEVER replaced an oil pump.

 

I went to a mechanic with a bent wheel stud on my SSS.

 

He notices my oil lines are leaking.

 

They really were, so I said go ahead and change them.

 

I drive it home and then to work the next day and stop at McD's for breakfast. Come out from McDs and I go to start the truck. The oil pressure is zero and the chimes are screaming! I shut it off, check the oil and it's full. I figure it's the sensor so I start it and listen and slowly the lifters start to tick. I shut it off. I know it's not getting oil. I towed it to the shop.

 

Now the mechanic says it's a total coincidence, but the oil pump is shot.

 

I drove in there needing a wheel stud and now my truck has no oil pressure! ????

 

I call bullshit and negligence.

 

He said the new lines came in a sealed package.

 

I HAVE to think something happened, even if it's not their fault, but SOmething blew that pump. Maybe it wasn't primed right? I don't know. I won't get screwed again. BUT, this is a reputable mechanic? I know he is. Many people I know trust him, but I feel they had to have made a mistake.

 

My thoughts, I'll pay for the part, but not the labor. That's fair. I'm getting a new pump, but THEY have to admit some fault.

 

What should I do?

 

Livid,

-Matt

[turboed ss]

idk if it would be there fault b/c the oil pump is at the front of the motor behind the engine plate... if they only replaced the oil cooler lines than they were no where near the oil pump... but i think i would be looking more at the oil pressure sending unit... the oil pump is mechanical and drivin of the crank so it cant just stop working without something else being wrong... but an electic sending unit can... i would stick a manual oil pressure gauge on it to determine the real oil pressure dont just listen to it... u need to vaerify there is a problem before throwing time and $ at it.... just my opinion!!!

[yembo77]

Yeah, they did and confirmed it's not pumping oil, but then they also said they don't know why the pump failed? The Check valve wasn't stuck open and the pump looked functional, but apparently the new pump has done the trick?

 

I've researched the pickup tube o-ring now and I wish they would have called me to let me know they were doing this. I would have had them do the timing chain too while they were in there. I'm at 100K miles now, so it would have been $35 dollar insurance.

 

-m

[Fireman31]

This happened to another member about 1-1/2 years ago, oil pump just quit on him. It is rare, but I guess it does happen...

[Nevada79]

I have had two oil pumps fail in similar fashion. Not after cooler lines replacement but just no oil pressure upon restart. When I put my 408 in I reused the low mile factory pump that was on the 6.0. I made it 480 miles before it would not start and you could hear the lifters ticking so I knew it wasnt making oil pressure. I removed the oil pump to find the relief valve not stuck and the pump gears ok. I removed the relief valve and noticed some scoring on the relief valve and bore. So it appears that it was stuck at some point and probably during removal it dislodged itself. I put another pump in and pickup tube o-ring in and it started right up.

 

The truck made it 2500 miles more before doing the same thing. Ran fine before I shut it off, went inside Summit to look around, came out 5 minutes later and nothing. I bought a Melling oil pump, the high flow high volume unit this time thinking the better pump might do the trick. During disassembly I was more careful and first removed the oil pump cover and immedately looked at the relief valve. It was stuck this time. After removing it I had to take a pick and pry to dislodge the relief valve. The valve and bore had more than normal wear on them. I think these failures are due to a possible short lack of oil or aeration most likely caused by my motor running 1 quart low for a short period of time at higher rpms. I didnt realise that it was using oil at the rate it was being I was used to the stock motor that used no oil at all. I gapped the 408 rings to withstand a 300 shot so it makes sense looking back having wide ring gaps and a shorter skirts on the pistons that it would use more oil.

 

So I have a question. Was the engine ever run low on oil, possibly when the lines were leaking? I am thinking (probably wrong) that it might have been a little low on oil at some point causing the relief valve to not have oil surrounding the valve itself and causing it to hit and score the relief valve bore. This showing itself later when you shut the truck off and the scored valve happened to align itself with the scored bore and the valve stuck. The mechanic removing the oil pump was probably enough to unstick the relief valve without him knowing. Do you still have the pump? I would bet that if you removed the relief valve you would find the evidence of the valve hitting the bore.

 

My guess as to the lines causing the oil pump failure is it is possible. As the lines were removed leaking whatever fluid they held in them. The engine upon restart (unless the mechanic anticipated it needing more oil immedately to make up for lost oil in the lines and adding a quart before startup) was low on oil at first startup until he rechecked the oil level and topped it off. The engine idling low on oil for the short period of time after the pump install would probably do nothing detrimental to the oil pump. Any damage to the pump is probably from previous damage to the oil pump caused by whatever. I think these oil pump failures are from low oil levels even temporary causing damage to the relief valve. This is possible from leaking cooler lines. No matter the case I think the mechanic probably isnt at fault. The part maybe faulty or the engine was low on oil but I dont see any logical way he could make the oil pump fail unless he didnt make sure the oil level was full after installing new lines. Did you check the oil level after the line work was completed?

 

I'd be curious to find out if the engine was run low on oil and the condition of the failed oil pump. Just trying to figure the oil pump failure out myself. Thanks for sharing and I'll shut up now.

[yembo77]

Awesome, and yes, this was my train of thought. I honestly DO believe that this was a coincidence and not negligence on the mechanics part. The WHY, though, is something that I was wondering too. How could it just go? The gears looked fine, but then why did it not pump? Your post just threw a whole new light on the scenario. Thanks. That's most likely the case. I don't have the pump, but when it failed I did check the oil and it was fine. And my oil lines were leaking, but there was no oil level indicator telling me to add oil and it was changed about 500 miles prior, so the level was no more than a half a quart low. The leaking lines were decent, but not blown. I believe you're probably right about the scored relief valve. What other explanation is there.

 

So the mechanic had the same doubts and bad feelings I did. He charged me normal price for the part, not retail, and only a couple hours labor. New pump, o-ring, gasket set, and 6qts and a new filter for $400. We were both happy with the deal.

 

Thanks!,

Matt

[brobradh77]

My pump went out a year ago...It was fine to pick up me daughter at school and then when i started it back up it made all kinds of racket....I've heard the oil pump has been a problem over recent years in all chevy trucks...the friend who helped me change mine said it was the 3rd one in a months time he has changed.