Oil light on & then off at 1500 rpm

KeighJeigh · **Posted:** Fri Apr 23, 2010 8:53 pm

Driving along the highway, stopped at a rest stop. Oil light goes on as I pull in to park.

Light went off once I revved it up, but it came back on at idle.
I got back on the highway & it was fine as long as the engine was up to speed. When I went back down the other side of a mtn pass & the engine went to low rpm, the light came back on.

I drove it around town checking & looking scratching my head.

Thus far:

* Changed the oil - which I change every year or so w/Mobile synthetic 0-40 as recommended in the manual.
* Changed the filter
* Cleaned the sensor (the one on the filter mount - is there another??)
* Worried

Most likely:

Since it goes off when revving - A plugged intake tube screen.
Other: Bad oil pump, bad bearing, bad sensor.

- Chris

racertracer · **Posted:** Fri Apr 23, 2010 9:12 pm

KeighJeigh wrote:

Driving along the highway, stopped at a rest stop. Oil light goes on as I pull in to park.
I didn't check the level but had an extra quart, so added it. It was a remote area, so I didn't have much choice anyhow.

Light went off once I revved it up, but it came back on at idle.
I got back on the highway & it was fine as long as the engine was up to speed. When I went back down the other side of a pass & it idled, the light came back on.

I drove it around town checking & looking scratching my head.

* I tried changing the oil, filter & cleaned the sensor (the one on the filter mount - is there another??)

It still does it.

Have a critical job interview tomorrow . . . might have to miss it because of this %(&* mule.

Ideas?
I'd hate to think bad oil pump but . . .

- C

What oil have you been using ?
what is your mileage?
What is your oil change frequency?

You may have sludge build up which in turn may be reducing or increasing the oil flow / pressure.

Oil in this engine flows thru very tiny orefices (sludge is a no no) so it is inperative to change the oil at the correct intervals and use the specified synthetic motor oil.

Well that is my take on it anyway ....

:POPCORN:

mag03kj · **Posted:** Fri Apr 23, 2010 9:18 pm

If its sludge...well i know on gas..you can idle 1 quart of kerosene in the oil for about 10 mins and it will get the sludge out!

flman · **Posted:** Fri Apr 23, 2010 9:50 pm

You need to get a mechanical test gauge and see if your sending unit is reading right. If you are lucky it will be a bad sending unit. Sludge is a thing of the past, especially with synthetic oils, I have never seen sludge in a diesel engine personally. If you have confirmed low oil pressure, you need to stop driving it immediately and pull the pan and see what is up. Sorry, maybe you should get a rental vehicle, would be alot cheaper then a blown engine.

KeighJeigh · **Posted:** Fri Apr 23, 2010 10:07 pm

racertracer wrote:

What oil have you been using ?
what is your mileage?
What is your oil change frequency?
You may have sludge build up which in turn may be reducing or increasing the oil flow / pressure.
Oil in this engine flows thru very tiny orefices (sludge is a no no) so it is inperative to change the oil at the correct intervals and use the specified synthetic motor oil.

- Mobile synthetic 0-40
- 56K
- Every year or so

KeighJeigh · **Posted:** Fri Apr 23, 2010 10:41 pm

OK, I've got the gauge.
The guy at store recommended changing the oil again - but this time when hot. That makes some sense, so I may drive it around the neighborhood a bit before draining draining the oil out again. (Which I should probably do before changing out the gauge or risk a serious inky mess.)

Does anyone know the correct oil pressures I should be watching for on this gauge at idle and driving RPMs?

KeighJeigh · **Posted:** Sat Apr 24, 2010 4:09 am

Update:

I found the pressure stats in the manual:
Minimum Oil Pressure (Warm) 0.7 Bar (10 psi.) @ Idle
2 Bar (29 psi.) @ 3800 RPM

I also warmed it up & drained the oil so will refill & check the pressure.

If it's off, I may have a nightmare scenario. I checked the manual on what's involved in pulling the oil pan: :furious:

Pulling the engine half way out - which requires one HELL of a lot more work than any engine I've ever overhauled (old ones) as well as buying special tools, rentals and at least a week's worth of work.

I think before doing that, I might try to irrigate the intake screen in the sump - perhaps attach an extension off my parts washer pump and just aim it up at it through the drain plug hole. (Anyone ever heard of this being done?)

OR perhaps a get a bit more radical and cut a hole in the bottom of the sump and replace it with a plate. (It's flat)

If I have to change the oil pump: Forget it. :dead:

- Chris

flman · **Posted:** Sat Apr 24, 2010 7:40 am

You are getting all doom and gloom here, but did you do an accurate test of oil pressure yet?

turbobike · **Posted:** Sat Apr 24, 2010 8:52 am

I had(have) a similar issue. Oil lite would ocassionally come on at idle...a slight rev of the engine & it goes away. Sometimes lite would come on just driving on a flat, level road. Sometimes it would come on going downhill. No rhyme or reason when it would come on. I changed the oil....no difference. I changed the sensor, and for the most part, it has stopped doing this. It still comes on for a sec when I start out with a cold engine, but goes away as quickly as it comes on. NO strange engine noises. I bought Jeep used from local, reputable dealer, but w/little service history, so I don't know oil change history. Hopefully regular changes will clear out any crap and the problem will go away.

'05 CRD, 87k miles, using Rotella T6 oil

CATCRD · **Posted:** Sat Apr 24, 2010 9:01 am

Rest easy, it's much more likely that the pressure sending unit is bad than your oil pump. Especially if the engine hasn't seized by now, it's probably just the sensor.

geordi · **Posted:** Sat Apr 24, 2010 12:14 pm

x2 on it just being the sensor.

Take it from my experience: If you were having an oil delivery problem, the #1 cylinder would have failed within just TEN MILES of driving.

KeighJeigh · **Posted:** Sat Apr 24, 2010 12:52 pm

OK, I took my prozac, changed the oil again, hooked up the gauge and took it for a spin. After 20 minutes of driving to get it nice & warm:

19 psi @ idle RPM (manual says should be 10 minimum)
70 psi @ 4K RPM (29 minimum)

It's a cheap $16 gauge so I don't know how accurate it is, but the pressure is definitely not "0" at idle.

There are no strange bearing noises, no overheating issues, it's running very smoothly, (although it's been tough to start lately) getting 31 mpg highway. So, is it safe for me to put away the bottle of Prozac? True story: I was awakened by my wife at 9:30 as she was searching where the hell I was . . . . I had fallen asleep in the front seat of the damnthing while checking codes on the scanner! The last time I remember checking the clock it was was 4:30 am.

Next up:

- Best best place to buy a sending unit? The stealer want me to give them $102 for this thing because it's a "special diesel unit". Yeah right.
- What to do with that gauge. It's nice to glance at once in while but I'd hate to think I was relying on having to glance at the gauge all the time to catch any oil pressure problems. Perhaps there's a "T" of some sort that allows both the sending unit and gauge to be used?? (I'm also wary of making the interior of this thing look like some teenager's 1970s muscle car with gauges all over to make it look faster.)

- Chris

flman · **Posted:** Sat Apr 24, 2010 2:38 pm

You should just replace the sensor, and keep the gauge for next time.

Best deals and quick shipping is here. http://www.moparonlineparts.com/ But they are in NY, so you might want to find some one closer to Washington. Glad it all worked out well for you.

Bob

turbobike · **Posted:** Sat Apr 24, 2010 2:41 pm

I recently picked up a sending unit on Amazon for $30 plus shipping.

VMKJCRD · **Posted:** Sat Apr 24, 2010 2:51 pm

flman wrote:

Best deals and quick shipping is here. http://www.moparonlineparts.com/ But they are in NY, so you might want to find some one closer to Washington. Glad it all worked out well for you.

Bob

That place is 20 minutes away from me. :BANANA:

KeighJeigh · **Posted:** Sat Apr 24, 2010 3:16 pm

flman wrote:

You should just replace the sensor, and keep the gauge for next time.
Best deals and quick shipping is here. http://www.moparonlineparts.com/ But they are in NY, so you might want to find some one closer to Washington. Glad it all worked out well for you.
Bob

Thanks guys!
This forum saved my asss once again.
Mopar online parts = $35 How the HELL can the stealer justify nearly 3x the price? I understand some extra markup but come on.

stoutdog · **Posted:** Sat Apr 24, 2010 3:42 pm

KeighJeigh wrote:

flman wrote:

You should just replace the sensor, and keep the gauge for next time.
Best deals and quick shipping is here. http://www.moparonlineparts.com/ But they are in NY, so you might want to find some one closer to Washington. Glad it all worked out well for you.
Bob

Thanks guys!
This forum saved my asss once again.
Mopar online parts = $35 How the HELL can the stealer justify nearly 3x the price? I understand some extra markup but come on.

You answered your own question there mate! :ROTFL:

linewarbr · **Posted:** Sat Apr 24, 2010 4:58 pm

Next time you need a part you may want to try www.moparpartsamerica.com . I believe they are in Oregon, so a lot closer/ quicker on shipping.

Putting this thread in the mental file. . . . .

KeighJeigh · **Posted:** Sun Apr 25, 2010 12:14 am

Turns out NAPA in town had one for $40 so I went ahead and got one. I just tested it with an Italian tuneup on a 1400 ft climb; No light. (At least no oil light. The CEL I can't solve and the damm TPS lights I can't seem to clear are another topic.)

Moparpartsamerica - that's the one I was trying to remember. I bought an EGR from them once at a fraction of the stealer's price.

Thanks!

- Chris

Oil light on & then off at 1500 rpm

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