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Discussion Starter #1
Help please..

I have had a bit of an issue with my oil pressure gauge for some time now... From cold I get a really good reading.. however once warmed up the issue occurs when I slow down/stop. the needle drops to zero! however as soon as I start driving again or give it a rev the needle goes back to a healthy position?

Where should I start looking or is there an easy test to see what is at fault. i.e. gauge or sensor?

Thanks for any help...
 

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if it drops to zero yet the low oil pressure warning light doesn't come on - this has a separate sender on alternator side - means it is not actually at zero. That warning sender kicks in when pressure drops below about 5 to 7psi and is way more reliable than the pressure sender itself.

simple test for the gauge is to remove wire from the sender and ground it....gauge should steadily climb to max.
the pressure sender (on starter side) is usually the weak link - they can be tested with an ohms meter:
oil pressure gauge - Alfa Romeo Bulletin Board & Forums

I'd leave it...if it gets worse and worse, then change the oil pressure sender.
When mine went awol, it just went from good to zero!

The only real way to see exactly what oil pressure you have, is to plumb in a manual pressure tester.

ps. If you do replace the sender, you need the right one to match your particular instrument!

Dom
 

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The guage is not accurate. Problem is it is such a small needle range it's hard to see what is happening. I'd be tempted to check with a mechanical guage if you are concerned.

Before the engine rebuild mine did as yours, but all was fine. Post rebuild it does much the same max reading as before so the guage/sensor must be at it's limit.
 

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Discussion Starter #4
Thanks Dom... No red warning light showing... I will give your suggestions a try and see what I can find out... I may well live with it!


if it drops to zero yet the low oil pressure warning light doesn't come on - this has a separate sender on alternator side - means it is not actually at zero. That warning sender kicks in when pressure drops below about 5 to 7psi and is way more reliable than the pressure sender itself.

simple test for the gauge is to remove wire from the sender and ground it....gauge should steadily climb to max.
the pressure sender (on starter side) is usually the weak link - they can be tested with an ohms meter:
oil pressure gauge - Alfa Romeo Bulletin Board & Forums

I'd leave it...if it gets worse and worse, then change the oil pressure sender.
When mine went awol, it just went from good to zero!

The only real way to see exactly what oil pressure you have, is to plumb in a manual pressure tester.

ps. If you do replace the sender, you need the right one to match your particular instrument!

Dom
 

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Discussion Starter #5
Thanks, I assume yours stays on max now even when stopped?


The guage is not accurate. Problem is it is such a small needle range it's hard to see what is happening. I'd be tempted to check with a mechanical guage if you are concerned.

Before the engine rebuild mine did as yours, but all was fine. Post rebuild it does much the same max reading as before so the guage/sensor must be at it's limit.
 
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