Opinions on oil pressure problem on '99 Chrysler Cirrus

I have a '99 Chrysler Cirrus with 226K miles. Yes, this is the same one that I posted about a while back when it turned 225K. I'd like to get opinions.

The oil pressure light started coming on at idle, but there was no lifter noise whatsoever. It seemed to only do it when it warmed up. I first thought it was the sender since I couldn't hear any lifters. I replaced the sender and drove it another day. When I got home that night, the light started coming on again - but it still sounded great (no noise). I also tried 20w-50. This didn't change anything either.

Then, I was telling a friend about it and I tried to get the car to do it by letting it idle and watching for the light. It ran for a few minutes, but the light never came on. Then everything in the head started rattling but the oil pressure light was NOT on. I turned the car off and immediately restarted it and the lifters were QUIET for another minute or so. Then the lifters rattled again with NO oil pressure light. I turned the car off again and immediately restarted it - same thing - completely quiet once again. I did this a 3rd time with the same results.

I thought if an oil pump was failing that it would be consistent, not random. I also thought it might not be draining back fast enough, but I thought it would still rattle on an immediate restart. Also, when the lifters were noisy, why was there not an oil pressure light? Any ideas?



http://mmb.maverick.to/showthread.php?t=58866

 

Is this a 2.7L V6?

 

Whoop - I forgot to post that. It's a 2.5 V6 (a Mitsubishi motor).

 

What oil filter you running? Try a wix, napa, just stay away from fram. Also, I would change back to 10-30 or 10-40. Good Luck.

 

I think it's got a STP on it now. If it was a filter, wouldn't the problem be gone when I changed it? I replaced the filter when I put the 20w-50 in.

 

Back in the 70's when stp first come out with filters, I ran them. My 390 would clack on valves for several seconds after start up. I was running 20-50 oilzum. I went to the cheapest walmart filter which stopped valve clack. I changed oil every 1,000 miles on that engine. -69 Mach 1-

Newer engines are different an oil has much imroved since then. Some filters filter to hard an drop oil pressure, there are other reasons they drop oil pressure, new STP filters I have no idea on. Be me, I would get a napa, 10-30 oil an see if it helps. The thicker oil could very well be hurting you. Always best to run what called for with possible tad heavier on high mileage.

Bob the Oil Guy has lots of great info on his site. He change my way of thinking on newer engines.

 

Thanks. I was wondering if the thicker oil would do any good and possibly make it worse. I ran 10w-30 in it before.
There's no lifter noise on startup. So far, the changes in weight and filters have made no difference.

 

Mitsubishi motors are known for lifters tapping try adding some bg MOA to quiet them down, try checking oil pressure with a guage it should be 6 psi at idle and 35 to 75 psi at 3000 rpm

 

may be a faulty oil pressure regulator or the pump it self. I've seen some cars that have the valve in the cyl head. i presume this is a 24 valves correct?

 

Wow, Darren should have an answer for this.

 

those engines have a "rotor" style oil pump. i'd almost bet it's about to go out, completely. it's happened before to others Chryslers that ive worked on but those engines in those cars are hard to come by so ive never seen them do it, but ive also only seen about 5 of them in existance.

I was a Chrysler 5-Star Tech for 4 yrs after high school

 

what Mean said...The geroter style pump is driven off the front of the crank shaft on those engines.The driven part of the pump...the rotor, eats the housing it rides in causing excessive clearance and low to eventually no oil pressure.PITA to cahnge as the engine is of the OHC type mounted facing in the wrong direction.

 

Thanks. I new it was the rotor style pump. I had a Saturn with the same thing. I was afraid it was a pump, but I was hoping there was something else going on. I've checked with the local parts stores and nobody sells the pump. But, I found it online for $280. This car is only worth so much money, so I'm don't know how much I'll put in it.

 

If it's what i'm thinking it needs the pump AND housing. The housing is what wears and is not serviceable.

 

if nothing else you can always check with your local Dodge dealership. sometimes factory parts arent as high as people think....