low oil pressure

[GATS]

:dude:help, i had just fitted a oil gauge to my stag, checked that it was not leaking, and thought i go for a ride to how well my oil pressure was. i was going quite well, oil pressure at 50psi, then i spotted a sport car ahead, and thought i will catch it up, i reached 90 at one point, and looking down at my oil gauge saw that the needle was way to the left and the oil light started flashing!!. well i nearly filled my pants, my heart pounding i slowed down to around forty, i had to find a garage to obtain some oil, i had to go about five miles to find one, pull in and check the oil, it was ok?. i creeped home, and was just so glad to have made it. but whats wrong???. do anybody knows??. paul

[Greenstag]

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Hello GATs

I'm no expert on this and I'm sure one of our more knowledgable members will come back with something more helpful.

What have you changed on the car... was it just the oil guage...was this possibly a problem that has existed before ... did you fit a new sender unit that is now alerting you?

I think I'm right in saying thatas you increase speed and therefore engine temp your oil will become thinner and create less pressure ... did you change the oil for something thinner?

Hope you get to the bottom of this and it's not too expensive

David

[GATS]

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:dude:hi dave , yes i replaced the sender as i broke the old one getting it out. even though i asked for a replacement for a stag, are there different one for different pressures, and is it normal pressure for a stag??. i know i am hopeing that its normal, and i will notneed work on the engine. i would not haveknown about this problem if i had not changed the sender and put in a oil gauge, and would have carryed on driving till who knows what would happen!!!. paul

[DJT]

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Paul,

What switch did you fit? I would suggest one of these: http://www.ldpart.co.uk/shop/shop.ph...9bb36ca83e8824

Contact Peter through his site and you will probably get it tomorrow or Thursday at the latest.

Oil pressure for the Stag (standard oil pump) should be around the following:

Cold tickover or hot running 40-50psi

Hot tickover around 20-25 psi.

The light should come on around 6psi. The worry is that the gauge showed very low pressure as well as the light coming on with the engine at high revs. The gauge is independant of the switch (I assume you have a mechanical gauge not electric).

Tim has already asked what oil you used. Good quality 20W/50 is fine.

It could be a coincidental spring failure on the oil pump pressure relief valve. (grasping at straws here).

Have you started the engine again since it cooled down? Are there any ominous rumblings coming from deep within?

Dave

[GATS]

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:dude:hi dave thanks for the reply,i have ordered a new switch from ld,s. the car started at 50psi, and when hot at 20psi, andyou say thats normal??. and theres no noise down below. paul

[StagnJag]

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Your pressures sound pretty much as mine are. 40psi @ cold idle, runs at approx 40psi and 20psi @ hot idle. If you are getting those readings then it must be your replacement sender unit that is dud.

Rgds

Dave

[GATS]

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:dude:hi dave, i have at last changed my oil sender, at start up pressure is 50psi- hot its around 18-20psi, y0u says thats normal!!, at idle the oil and brake light flickers, but goes off when engine speed increases. paul

[seaside bill]

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GATS wrote:

:dude:hi dave, i have at last changed my oil sender, at start up pressure is 50psi- hot its around 18-20psi, y0u says thats normal!!, at idle the oil and brake light flickers, but goes off when engine speed increases. paul

Gats

When you say "hot it's around 18-20psi" do you mean at idle or running?

[stustag]

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GATS wrote:

:dude:hi dave, i have at last changed my oil sender, at start up pressure is 50psi- hot its around 18-20psi, y0u says thats normal!!, at idle the oil and brake light flickers, but goes off when engine speed increases. paul

Hi Paul

My oil pressure is 25 psi HOT idle and 50 psi at 50 mph hot! I think you don't have a pressure problem but an electircal problem.

Try cleaning all conection related to the brakes and oil sensing systems and see if the problem persists?

Stuart

[seaside bill]

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stustag wrote:

GATS wrote:

:dude:hi dave, i have at last changed my oil sender, at start up pressure is 50psi- hot its around 18-20psi, y0u says thats normal!!, at idle the oil and brake light flickers, but goes off when engine speed increases. paul

I think you don't have a pressure problem but an electircal problem.

On earlier cars the brake light is the test for the oil pressure bulb - they're wired in series so the oil pressure switch controls both. A problem with the PWDA will only illuminate the brake light on its own. If you only have 18-20 psi when hot running (as opposed to idle) then I suspect you have a problem. Assuming your replacement switch is ok, when the oil light is on it's indicative of pressure below 5 psi.

[tonypy1]

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Why bother fitting an oil guage, it'll only distract you from the temperature guage!

I ended up selling mine on e-bay, you can have engines with hot oil pressure considerably lower than 20psi that will still run for years. You'll be able to hear and even see the effects of a badly worn engine. I'll probably get lynched for this but I just think it's one extra thing that you're better off not worrying about.

If you must have an oil guage just be really careful routing the feed pipe any "chaffing" and they can wear through and deposit hot oil all over the engine bay or your leg.

[Greenstag]

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RE: they can wear through and deposit hot oil all over the engine bay or your leg.

Yes I can certainly vouch for that one.... happened last year when we were in the Isle of Man. New wiring, carpets, trousers, socks, shoes...could have been worse could have been wearing shorts

[GATS]

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:dude:hi tony, yes i would agree with you about that, i didnt worry when i didnt have a oil gauge, now i can,t help looking at the darn thing, and i did not have the oil light flicking on and off!!. i might think about taking it off. paul

[stustag]

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Hi Paul

can you clarify something for me is the low reading when the car is hot and idling or hot and revving under load ie at say 50 mph?

If at idling and as you say the lights didn't flicker before then you may have disturbed some wiring whilst installing the oil guage!

Stuart

[DJT]

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GATS wrote:

:dude:hi tony, yes i would agree with you about that, i didnt worry when i didnt have a oil gauge, now i can,t help looking at the darn thing, and i did not have the oil light flicking on and off!!. i might think about taking it off. paul

Did the oil light not flicker before you fitted the oil pressure gauge? If that is the case, then something to do with the installation of the gauge is affecting the oil switch.

I nearly s*** myself on a post engine rebuild shake down run a few years ago when the oil pressure disappeared. Pulled over and could see nothing wrong. Drove home carefully and pulled the gauge only to find a small piece of PTFE tape blocking the filter at the rear of the gauge. Removed this, reconnected the gauge and tried again to find oil pressure restored.

If I were you, I would return to where you were before this problem started and see if the oil light flickers. If it doesn't, then either forget the gauge, or review how it is connected.

Dave