Oil Pressure Trouble

**gotta go** · 03-05-2010, 12:53 PM

Has anyone with the Cummins ISC engine had an oil pressure problem? For 3 years my gauge had read between 65 and 70 lbs when 1425 to 1500 rpm. Then it started dropping. The first shop I went to said 50 lbs is within specs, no problem. Second shop, told me the gauge reads 12 lbs high, okay, still not reading what I'm used to seeing. They then decided that the spin on filter had collapsed. Replaced that and oil pressure was right back up to what I expect. All's good for the next 8,000 miles.
By the way, I had put the Gulf Coast Bypass Oil Filter System on 6 months after buying truck.
Back to my saga, oil pressure dropping again, down to 40 lbs, truck seems a little sluggish, or is it my imagination? Into another shop, nothing wrong, within specs (hysterical female syndrome). Agree to change out spin-on filter, pressure right back up.
A month later, pressure is dropping. I pull into Petro, say change out filter, they do. All is good. By the next time it's time to do by-pass service, pressure is low again. Go into a shop with a good reputation for high performance and problem solving. Am told there's no problem, gauge is just reading different as years and miles go by. (I think it's getting the sags like me.)
I've been trying to ignore that gauge sitting at 50 lbs, but this week it kept dropping and got down to 35, along with red shut me off NOW light and buzzer. I was on the east coast and had a load back to Ohio, so I found a small shop and had him switch out the spin on. Pressure is right back up to 70 lbs.
This last mechanic suggested putting it on a dyno. Any other suggestions?
Sorry the post is so long, I didn't want to leave out vital info. I do use Fleetguard filters.

**LDB** · 03-05-2010, 01:00 PM

I'm sadly not the mechanical type but offer good wishes for a speedy solution. Hopefully Bob will get a chance to comment soon. He's very good on this stuff. Good luck.

**greg334** · 03-05-2010, 01:34 PM

Why wait for Bob?

Jeanie, take it to a Cummins dealer ASAP and let them look at it.

Don't mess around with different shops, go to the people who know the engine the best.

Depending on the year, it may be something that is not related to the oil system.

Also have a OA done on it to make sure there isn't something internal causing an issue.

BUT DON'T PUT IT ON A DYNO WITH AN OIL PRESSURE PROBLEM (sorry you can't hear me through your monitor)

Normal system pressure for the engine is 35 psi at 1500 RPM.

You mentioned you put on a bypass system?

There may be something wrong with the bypass system, most if not all of them work with a line hooked up to the main oil system with a restriction that feeds the bypass filter and if there is an issue with the restriction (*I seen one with a pressure bypass valve), it can drop the pressure down to nothing quick or bled off enough that it will have a pressure loss in the oil system.

The other thing is how did they know the oil filter was collapsed?

Did they cut it open?

**gotta go** · 03-05-2010, 01:57 PM

Originally Posted by greg334

Why wait for Bob?

Jeanie, take it to a Cummins dealer ASAP and let them look at it.

It's been to 2 different Cummins shops. Adventures # 2 and 3

Don't mess around with different shops, go to the people who know the engine the best.

Depending on the year, it may be something that is not related to the oil system.

Also have a OA done on it to make sure there isn't something internal causing an issue.

I have continued to have the oil analysis done by Titan Labs, they do all of the tests for GCF users and nothing has shone up.

BUT DON'T PUT IT ON A DYNO WITH AN OIL PRESSURE PROBLEM (sorry you can't hear me through your monitor)

I hear you.

Normal system pressure for the engine is 35 psi at 1500 RPM.

Would it change after 570,000 miles from what I'm used to seeing?

You mentioned you put on a bypass system?

There may be something wrong with the bypass system, most if not all of them work with a line hooked up to the main oil system with a restriction that feeds the bypass filter and if there is an issue with the restriction (*I seen one with a pressure bypass valve), it can drop the pressure down to nothing quick or bled off enough that it will have a pressure loss in the oil system.

I forgot to mention that I shut off the lines going to the bypass filter for about 5000 miles and had the same results.

The other thing is how did they know the oil filter was collapsed?

Did they cut it open?

No they didn't cut it open, but silly me, I figure, this is a Cummins shop they know what they're talking about.

Thanks for helping. I feel like I'm in a maze.

**piper1** · 03-06-2010, 01:59 PM

Jeanie, if your bypass filter has torn or otherwise developed an internal leak, it may be dumping all that sludge back into the engine and your full flow filter is now plugging up rapidly with all that extra "goo". There's only a few things that cause oil filters to collapse, heavy sludge contaminants and sometimes coolant contamination (enough that your oil will be milky colored) or poor filter quality.

If changing the filter brings the pressure back up to normal when the engine is at operating temp, there is nothing wrong with your gauge.

Agree that a factory Cummins shop is the place to go.

Good Luck!!

**iceroadtrucker** · 03-06-2010, 03:13 PM

I hope when u take it to Cummings that they do a hot oil flush on the entire system. with a cheese cloth attached to show the particulates.

Diesel engines are known for allot of soot so to speak. & high sludge.

You may find that they do a hot oil flush on the engine and change the pickup screen in the pan all might just be better will be better.

Then again, lets hope that's all it is. A weak oil pump or a cracked pick up tub could be relay costly.

But then again a messed up gage and sending unite can cause all kinds of Headaches.

**greg334** · 03-06-2010, 03:39 PM

Piper,
Never thought of the internal leak, there isn't any back pressure in the return line for the bypass so it would make sense.

**gotta go** · 03-06-2010, 06:44 PM

Originally Posted by piper1

Jeanie, if your bypass filter has torn or otherwise developed an internal leak, it may be dumping all that sludge back into the engine and your full flow filter is now plugging up rapidly with all that extra "goo". There's only a few things that cause oil filters to collapse, heavy sludge contaminants and sometimes coolant contamination (enough that your oil will be milky colored) or poor filter quality.

If changing the filter brings the pressure back up to normal when the engine is at operating temp, there is nothing wrong with your gauge.

Agree that a factory Cummins shop is the place to go.

Good Luck!!

Dave, since this is an ongoing problem the bypass filter elements have been changed 3 times. Are those the filters you have suggested may have torn? Analysis has shown no contaminants, no sign of coolant, level's not rising (no fuel in oil).

Piper, Never thought of the internal leak, there isn't any back pressure in the return line for the bypass so it would make sense.

Greg, can you explain to me what you mean about lack of back pressure?

You may find that they do a hot oil flush on the engine and change the pickup screen in the pan all might just be better will be better.

This makes sense to me as one of the steps I hadn't thought to try.

Thanks all, sorry I haven't figured out how to properly use multiple quotes.

**greg334** · 03-06-2010, 08:57 PM

A lot of by pass systems drain right back into the pan, leaving no back pressure in the return line. If there is an internal leak as Piper mentioned, then the oil just returns back to the pan without being filtered. I have faith that the Cummins dealer can figure this one out.

**gotta go** · 03-06-2010, 09:06 PM

okay, that makes sense to me. Thanks

**guido4475** · 03-10-2010, 07:56 AM

The Cummins dealer in Fort Wayne, Ind is extremely good as far as I am concerned, they are the only Cummins dealer I let work on my 8.3 (ISC).

Bruce Malllison of Diesel Injection of Pittsburgh is also extremely well on Cummins, and alot of his mechanics/technitions are retired from Cummins Engine themselves. They know Cummins inside and out.You'll be well pleased.I highly recommend them, nice facility,new,showers,etc.Real nice people.

As far as the bypass oil filter setup, I was told that the engines were desined to have oil in them changed at recommended intervals, so stick to it, and avoid all of the aftermarket products out there, because they will eventually cause problems in the long run.Which is cheaper,oil changes or an engine eventually? some engines were designed where oil pressure contols the fuel injectors (HEUI system).I just use regular oil and filters with Lucas and change oil at the recommended intervals, no problems with my high mileage engines.My last truck had 80 psi oil pressure at 875,000 miles, no internal work ever performed.

**gotta go** · 03-26-2010, 11:11 PM

Here's an update. Talked to Cummins Filtration today at MATS. It seems that the drop in oil pressure is not unheard of. They blamed it on changes in oil formulation and ultra low sulfur fuel. The last time I changed the oil filter I'd changed from the LF3000 to a LF9009. I was told that my troubles should be over with the up-graded filter.

**greg334** · 03-27-2010, 11:48 AM

I find that odd, oil breaking down suddenly?

There is something that I keep forgetting to ask when these issues come up, what oil filter is on the truck.

Hope this solves the problem.