No oil pressure

[Dieselcrawler]

has anyone ACTUALLY had an oil pump fail to put out any pressure but still move some to fill everything? Tried swapping a known good oil cooler incase the valves were stuck, no change. Changed oil and filter, no change. Mechanical gauge reads zero. Can crank it with ip unplugged, I do get oil out the sending unit hole but no geyser. Oil is not foamy so don't think pickup tube cracked. Thing had great pressure for 10-15 miles then gauge dropped to 0.

Engine is a bone stock 89 7.3 with 127k on it. Thing was spotless on the inside when we pulled the Tins to reseal. Runs very well. It is getting enough oil to fill lifters, barely.

Already called @Dsl_Dog_Treat but even he was stumped.

 

[Thewespaul]

Wow. Never heard of that before, any metal in the oil filter?

 

[Dieselcrawler]

Oil had a VERY light swirl in it. Nothing I was concerned about. I drained worse from engines. Lol

 

[Hydro-idi]

I would verify by putting an oil pressure test gauge on it, just in case your mechanical gauge is screwy. You can rent them from Azone.
If it's real low, than I would suspect oil pump is the culprit, especially if you swapped out coolers with same result.
But no, haven't heard of anyone needing an oil pump with these idi's, but I'm sure it's happened before.

 

[Dieselcrawler]

I had a mechanical gauge on it that I pulled off my other truck. I know it works. I don't rent crap from autozone. Lol

I just can't see it as a pump failure. It still moves oil, just no pressure and no change if you do rev it up to 1200 or so

 

[jwalterus]

has anyone ACTUALLY had an oil pump fail to put out any pressure but still move some to fill everything?

Yep, sounds like a repeat of my oil pump failure 2 years ago.

https://www.oilburners.net/threads/oil-pump-changed-in-the-truck.73764/


Pump gear spun on the shaft on mine, it'd move oil, but it wouldn't build pressure.
When I got it out and tore it apart, you could spin the gear that actually pumps oil on the shaft by hand with minimal effort, drive gear was tight.


OH!, I almost forgot......
Welcome to the club brother, it's pretty exclusive....... I believe that now makes a total of 4 forum members who've had one fail!

 

[Dieselcrawler]

What makes this worse is it isn't my damn truck. Side job I took on at home. 83 dually, 17 year old kid killed the 6.9. I sold him the engine that ran great for 500 bucks, then 400 to install it with his help. A week later he calls and tells me it's ticking. Well the tick is lifters randomly.

 

[rotarydragon]

has anyone ACTUALLY had an oil pump fail to put out any pressure but still move some to fill everything? Tried swapping a known good oil cooler incase the valves were stuck, no change. Changed oil and filter, no change. Mechanical gauge reads zero. Can crank it with ip unplugged, I do get oil out the sending unit hole but no geyser. Oil is not foamy so don't think pickup tube cracked. Thing had great pressure for 10-15 miles then gauge dropped to 0.

Engine is a bone stock 89 7.3 with 127k on it. Thing was spotless on the inside when we pulled the Tins to reseal. Runs very well. It is getting enough oil to fill lifters, barely.

Already called @Dsl_Dog_Treat but even he was stumped.

On a limb but I saw this happen with a 6.9 that blew out one of the piston cooling nozzles. Granted that was on an early block with the pressed in nozzle but just tossing it out there.

 

[riotwarrior]

On a limb but I saw this happen with a 6.9 that blew out one of the piston cooling nozzles. Granted that was on an early block with the pressed in nozzle but just tossing it out there.

Being that pressure is a measure of resistance to flow....this is entirely possible....

So blown out cooling squirter or spun shaft....any other spots like oil galley plug may have come out inside engine....that could do it to.

 

[tjsea]

Any chance the sump could be partially blocked with something?

 

[Dieselcrawler]

Any chance the sump could be partially blocked with something?

Nope checked that. Love my bore scope

 

[oregon96psd]

Just run it til it locks up, then take it apart to find out why.....it's more fun that way lol

 

[Thewespaul]

I don’t think 6.9s like this kid, maybe time to drop in a 7.3

 

[Dieselcrawler]

I don’t think 6.9s like this kid, maybe time to drop in a 7.3

That's what I did.... the 7.3 is the one with the oil issue. I am leaning towards gear on the pump came loose. He said randomly it will get gauge movement, which means the gear grabbed.

 

[Thewespaul]

Ahh thought there was another 6.9 thrown in, man that stinks. Are you gonna replace the engine again or try to replace the pump?