Oil Pressure and IDLE

I just changed my oil, with Mobil 1 synthetic as usual and was wondering why all of a sudden my oil light goes on when my car gets warm, the oil light only goes on at idle, but my idle drops to a steady 650rpm instead of the usual 750rpm, when I rev it up just a tad the oil light diminishes .... is this a serious problem what could be the cause of it?

Thnx

Marko
license [AWD TSI]

It could be possible that your pressure sending unit is going bad, that would be why you get an oil light (Low oil pressure). I had a similar problem on a previous car, had to change the unit every two years...

Adjust your RPM to 750 and see if the light goes away. If the oil pump would not pump enough oil pressure your engine would of blown by now.

Did you change oil viscosity last time you change the oil??? That can also affect the oil pressure.

Don't know if you guys ever notice but the oil pressure is always higher when you first start the engine. Then as the engine temp increase the pressure drops. (It's not only cause the RPM decrease as the engine gets warmer)

Oil becomes more fluid when hot, we all know that. It has a direct effect on pressure.

I work in the aviation industry and each time we run an engine we have to wait for the oil pressure to stabilize before we increase the blade angle (Turbo prop). This way we don't only add a load to a warm engine but we confirm that the oil pressure is as required.

Hope this helps.

Ghislain.

Ghislan.....
hmmmm i really don't think it is the pressure sending unit.. since the problem isn't contstant.. I use 5w30 Oil.... and i didn't change the viscosity...
My Rpm run at 750 when my engine is warm.. but after long driving distances, when idling it drops lower adn then the oil light flips on.... and as i said.. if i barely touch the pedal to increase the RPM the light disapears....
If i have a tad bit, or a tad less, oil in my engine will this effect anything greatly? and also could it be that there are "air bubbles" since it is a fresh oil change, new filter etc?


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Marko

License:
Ontario
[AWD TSI]
Yours to Discover

i have the same problem but mine light comes on just after the engine has been running for a few, i think it might be my oil presure sensor, but not to worried yet because the light will go off, but i noticed my presure is lower than usual. does your valve cover leak oil at all ? mine dose a little and that could be the problem. i dont know i try for the easy things before i think about the hard ones.

Im looking for a cluch , and someone mentioned center force ?????? should i go with the centerforce II ????

thanx
davey crocket

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1993 Eagle Talon DL 1.8L
Beats Walkin'
§TOKE§
icq 37160225

[This message has been edited by Panther (edited March 08, 2000).]

This seems to be a common problem when people switch to synthetic. I've noticed it when I switched, and I've seen it mentioned several other times as well. That's not to say the sending unit isn't getting out of spec, but it's probably nothing to worry about.

Marko,

I have the same issue with Mobile 1 Synthetic oil. I also use the 5-30 weight.
I'm planning on changing the viscosity this month to a 10-50 or so for the summer so we'll see if that makes a difference or not.

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If you go fast enough you can't hear anyone.
96 Black TSI AWD

Marko:

I have the exact same problem as you. What I was told is to increase the iddle speed a little bit. That's what I intend to do.

Yves

Thnx GUYS
So it sounds like my problem isn't really a problem at all!! )

My next Oil change i will put 10W-50 just as Edward will be... hopefully that gets that annoying flickering light off my dash.... and all this after i couldn't get rid of the bloody engine light... get rid of one and another pops up!!!

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Marko

License:
Ontario
[AWD TSI]
Yours to Discover

I had that start to happen, but it went away (at least so far...) after i changed the leaking oil pump sprocket seal.

I think 5w30 is too thin for our cars also, anyone care to comment? I use 10w30 in winter and 15w50 in summer (mobil 1)

Matt

Man i WISH i could drive my car only when it is still cold.... today my idle jumped to 1400-1900 when idling.... after a highway drive.... started stalling after a warm start... and that DAMN OIL light keeps on coming on..... and the worst part about this whole thing is that INDIGO BOOKS is TAKING 4ever to send me my SHOP MANUAL!!!!!! I can't even find the grounding for my ECU so i can check the timing.... or the BISS so i can check if that is my problem ...... IM SCREWED.....

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Marko

License:
Ontario
[AWD TSI]
Yours to Discover

Changed the oil to 15-50 Mobile 1 on the weekend.
Oil light still comes on when at idle.
Hmmmmm...

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If you go fast enough you can't hear anyone.
96 Black TSI AWD

Edward
Have you tried adjusting your base timing to around 750-800rpm?

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Marko

License:
Ontario
[AWD TSI]
Yours to Discover

Nope.


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If you go fast enough you can't hear anyone.
96 Black TSI AWD