Author Topic: Oil problem Can anyone explain (Read 464 times)

DREDIOCK · « **on:** September 14, 2006, 02:38:43 PM »

Ok Start the vehicle up no problems

When driving Oil pressure at its normal (Im guessing) 80 give or take

Drives fine for about an hour hour and a half then pressure begins to gradually drop eventually dipping below 40 where it will hold for a while.

then will slowly drop a bit more and then suddenly drop to zero, And then spike back up to 40, then down to zero again. then up to 40 again repeatedly.

Shut the vehicle off for a few minutes restart and pressure goes back to almost normal. then begins to drop again. again holding for a while (up to a half hour) at just under 40

Oil & filter changed regualarly.
Not low on oil and oil shows clean on the stick

In fact had it changed yesterday

Today, exact same thing happened.

Any answers?

rabbidrabbit · « **Reply #1 on:** September 14, 2006, 02:39:23 PM »

are you sure its not the guage or sender?

MiloMorai · « **Reply #2 on:** September 14, 2006, 02:50:31 PM »

Is the oil pump failing?

Mustaine · « **Reply #3 on:** September 14, 2006, 02:51:07 PM »

oil pump cutting in and out?

DREDIOCK · « **Reply #4 on:** September 14, 2006, 02:53:40 PM »

New oil pump. same problem
Replacement bad too??

Mustaine · « **Reply #5 on:** September 14, 2006, 02:57:08 PM »

relay that controls oil pump? (not sure what controls it's pressure and stuff on modern cars)

rpm · « **Reply #6 on:** September 14, 2006, 02:57:12 PM »

Sounds like possibly a bad sending unit or gauge. Try replacing the sending unit or piggyback a manual gauge with it and compare readings.

nuchpatrick · « **Reply #7 on:** September 14, 2006, 02:57:46 PM »

Could be a faulty sender. Only way to find out is to put/get a second gauge on it.

What kind of car/truck are we talking about.

DREDIOCK · « **Reply #8 on:** September 14, 2006, 02:59:13 PM »

Quote

Originally posted by nuchpatrick
Could be a faulty sender. Only way to find out is to put/get a second gauge on it.

What kind of car/truck are we talking about.

Van
2001 Dodge Ram 2500

icemaw · « **Reply #9 on:** September 14, 2006, 03:00:17 PM »

Is this an older car lots milage. Sounds like oil is pooling in the valve covers. Oil cant drain back to pan fast enough and after a while the level in the pan drops below the pickup hench the loss of oil pressure. When it starts happening stop turn off engine and remove oil cap look into valve cover for oil. There shouldent be any more than a film on the rockers etc etc.

Rash · « **Reply #10 on:** September 14, 2006, 03:21:00 PM »

One time I had this problem and it was a loose oil pickup, letting the pump suck air when I was turning, stopping/accelerating. Another time, I had obstruction (the paper lid gasket of an oil container) in one of the drains holes on top of the head, but only dropped the oil pressure when accelerating.

DREDIOCK · « **Reply #11 on:** September 14, 2006, 04:18:03 PM »

Quote

Originally posted by icemaw
Is this an older car lots milage. Sounds like oil is pooling in the valve covers. Oil cant drain back to pan fast enough and after a while the level in the pan drops below the pickup hench the loss of oil pressure. When it starts happening stop turn off engine and remove oil cap look into valve cover for oil. There shouldent be any more than a film on the rockers etc etc.

not that old I think. 2001 only 5 years going on 6

83K miles

Pisses me off as it ruined a rare and what will probably be a 1 time opportunity...two days in a row

eagl · « **Reply #12 on:** September 15, 2006, 12:06:15 PM »

Does it happen with a new oil filter? A bad oil filter with a faulty/intermittant bypass might do that.

Also, oil can crud up in older engines. There are some really thin oils that help break that stuff up, but you're only supposed to run them for a few hundred miles.

I remember reading an article about marvelous mystery oil once... It's a very very thin oil and if you dump a can of it into your oil, it thins it out and breaks up any clogged oil passages. You only run it for a few hundred miles, and then change your oil out normally. It's not something you want to run for a long time in demanding conditions, but it's a lot better off in the long run than slick 50 or those other treatments because the marvelous mystery oil cleans everything out, while the PTFE treatments deliberately add a buildup layer. Yea it's a slippery layer, but PTFE treatments can clog small oil passages over time.

The other thing it could be of course, is a bad oil temp or pressure sender. Those should be easy to replace and not terribly expensive either.

eagl · « **Reply #13 on:** September 15, 2006, 12:08:39 PM »

A bad EGR valve or air pump valve might do that too, if it clogs up and creates a vacuum up in the valve covers.

I'd change the oil and filter, possibly run through one of the oil thinning cleaning treatments, and maybe even change the pressure sensor. That's cheaper than pulling off the oil pan or valve covers to check for other problems...

DREDIOCK · « **Reply #14 on:** September 15, 2006, 04:04:45 PM »

First thing I did when the problem started was have the oil and filter changed.
Wasnt overdue but I had it done anyway.

Same thing. Then the pump
Same thing

Now if I start it the presure is fine...at first.
and holds good for a while..like an hour before it drops again

but the Check engine light is now lit reguardless of oil pressure