N14 Lost oil pressure

[mweiman]

I am working on an N14 in a New Holland tractor. About a 1993 model with STC system. Story is that tractor was running along in the field and all of sudden shut down, no oil pressure. They pulled it back to farmyard and the next day started it to move into shed. Engine started out at 70 psi but was dropping quick by the time they got it parked. Now it won't build any pressure on dash gauge or using a mechanical gauge. It has a mechanical gauge in the dash with a low pressure switch built into the gauge. I pulled all 6 piston cooling nozzles and replaced them, they were all fine when removed. Pulled the regulator out of the bottom of the oil pump and doesn't appear to be anything wrong with it. Replaced the oil filter, the oil in it looked good when dumped out. I removed a plug from the oil cooler next to the turbo feed line and it did pump some oil out, a good stream, probably shot out 5 inches from the hole. Anyone familiar or have any ideas? There is a large allen head plug in the gear case about even with the oil pump. I wonder if there is some type of flow control valve behind the plug. Tractor has about 4600 hours on it and looks to be very well maintained. Thanks for any suggestions.

 

[NIsaacs]

Possible cause:

https://www.thedieselgarage.com/forums/935059-post8.html

https://www.redpowermagazine.com/fo...ins-n-14-help/?do=findComment&comment=1233793

 

[Wayne M.]

Suspect that STC system. We had a thread on the system on a L10 recently, and the system can effect engine oil pressure. I will look for a link.

 

[Wayne M.]

https://www.turbodieselregister.com...nd-next-day-extremely-low-issue.267262/page-2
Read it all, but good info at post 35.

 

[mweiman]

I just reread the L10 thread, I remember that. I assume it is a gear pump for the oil pump? The main hydraulic pump drives off of the back of the oil pump and hydraulics seem to work fine so that rules out the drive gear slipping to me. Can the actual pump gears slip also?

 

[Wayne M.]

I doubt it. Look close into that STC system. It can really effect oil pressure.

 

[NIsaacs]

Can the actual pump gears slip also?

I guess you didn't read the links I posted?

Parts of both links.

, pulled the oil pump off gear just spins on drive shaft

then the gears are slipping on the drive shaft.

 

[Wayne M.]

I guess you didn't read the links I posted?

Parts of both links.

, pulled the oil pump off gear just spins on drive shaft

then the gears are slipping on the drive shaft.

Finally had a chance to indulge.
Hard to believe Cummins would allow something like this to happen in design.

 

[mweiman]

I removed the pickup tube tonight and could reach in with a screwdriver and turn the pump gear easily so I will order a new pump tomorrow. I will post back results when it is replaced.
Thanks,
Matt

 

[DonFitzwater]

Finally had a chance to indulge.
Hard to believe Cummins would allow something like this to happen in design.

Even our beloved Cummins has bean counters.

 

[jhenderson]

As I heard someone say, “ You can’t kill a Cummins, but they will commit suicide” .

 

[mweiman]

Had some issue getting the correct pump (part number tagged on the pump was different than ESN called for)but got it on today and had 75 psi at cold startup so everyone is happy.