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Low Oil Preesure When Engine Warm


nigelt
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Hi All,

 

I appologies that this has nothing to do with my 2B, but my daughters Corsa 1.2i twinport. However, with the wealth of knowledge on here I thought you might give me some ideas as to the problem.

 

As the Title suggests, the oil pressure light comes on at idle once the engine is up to temperature.

 

I have replaced the pressure switch as that seemed a good place to start according to all the info on the web, but its not that.

I have replaced the oil pump (a complete end of the engine, not cheap) so its not that.

Oil has been replaced and have flushed it at the last look but that has not improved anything.

 

 

I wondered if it could be a head gasket leaking once the engine is up to temp or a crack in the head opening when up to temp, but I have never heard of this before causing low pressure.

 

Yes it is loosing oil but no more than any other vauxhall that I have owned.

 

The oil pressure should be 1.5bar or 21psi at idle, but its at or around 1bar /15psi.

 

I'm at a loss as to where the fault might lie or how it manifests itself only when the engine is warm.

 

Any help would be much appreciated

 

Nige

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Guest chris brown

What mileage has the car done? It sounds to me like general wear ( oil changes missed in the past) the answer is a complete strip and rebuild or find a low mileage one from a written off one which may be the cheapest way out.

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I'm not savvy with vauxhall engines but it could be that the pressure is getting "bled out" of the main gallery somewhere; either a poor fit of some component around the oil pump, the pressure relief spring in the pump or stuff like that.

Or it could be something more detrimental like bleeding oil out of worn main bearings, or some sort of pressure limiter in the feed to the head has popped out, or a cam feed pipe, or something like that - so the pressure it just dropping off.

 

I think if the oil was dumping itself into somewhere it shouldn't be, 6 psi's worth of dropped pressure is enough to spot it pretty quickly (ie. in the water, or you'd be burning black smoke out the exhaust!)....

 

Really needs someone who knows the engine well in terms of design....

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What mileage has the car done? It sounds to me like general wear ( oil changes missed in the past) the answer is a complete strip and rebuild or find a low mileage one from a written off one which may be the cheapest way out.

 

Only 88,000 miles

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From the "Not at all helpful dept" in olden days we solved this problem with a neatly cut square of insulation tape -- stuck over the tell-tale lamp.

 

And slightly more useful --- what is the pressure when driving -- is that O.K

Edited by florin metal works
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From the "Not at all helpful dept" in olden days we solved this problem with a neatly cut square of insulation tape -- stuck over the tell-tale lamp.

 

And slightly more useful --- what is the pressure when driving -- is that O.K

 

Yes as soon as engine revs creep up to 1000 rpm oil light goes off and pressure is at about 45 psi at 2500 rpm and above. Can't remember what the pressure is at 1000rpm but more that 15psi

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What oil are you using, a slightly heavier oil may give a bit more pressure,

Is there no knocks or rattles, and where is it leaking from?

 

jon

 

The oil should be 5w30, but I have tried 10w40 with no improvement. I suspect that the oil is being burnt as I can see no leaks anywhere, but no blue smoke that I can see :sorry:

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Guest mower man

Has it ever been run shall we say short of oil ? it just could be some premature wear on the crank you have covered every thing else and it dosnot take long to take a little out of mains and big ends to drop pressure at low rpm , I would be thinking of moving it on to be honest mowerman :sorry:

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"""I have replaced the pressure switch as that seemed a good place to start according to all the info on the web, but its not that.

I have replaced the oil pump (a complete end of the engine, not cheap) so its not that.

Oil has been replaced and have flushed it at the last look but that has not improved anything."""

 

There is really only one thing more to do, get another pressure test done with another gauge, probably worth getting a garage to do a pressure test with external gauge, if this reads low then big ends wearing

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Thanks guys for all the input, that's given me some food for thought.

 

Probably is the big ends, been a long time since I have had to sort them out on an engine.

 

Cheers

Nige

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