Oil Lo Press Light On When Engine Fan Cuts In

[Guest holmestr1972]

When i run my crossflow and get stuck in traffic engine gets warm fan cuts in but my oil pressure drops light comes on is this possible the oil which is 1 week old is foaming due to hi temp the light goes out when you rev the engine is it because it is starving the engine????,i have good pressure when at normal temp.

[Guest holmestr1972]

I forgot to say that the head has just been modified with new valves,seats done etc

[Grim]

sounds like an earthing problem in your electrics. Check your earths!

[Guest holmestr1972]

The light seems to come on when the engine is warm??and i get a reduction in oil pressure on my guages BUT when i rev the engine i get good pressure again??

[Longboarder]

Painfully it's more likely that when the engine gets hot the oil gets hot, it's viscosity drops and it leaks out of the worn main and big end bearings more quickly and the oil warning light and the gauge are telling you the truth. Oil doesn't foam just because it gets a bit hot. Your oil pressure is low. The new oil may have cleaned some of the old crud from the engine opening up some gaps. I think you are looking at a bottom end rebuild, possibly just main and big end shells if the crank bearing surfaces are still in spec.

 

Nigel

[Guest russell555]

i had the exact problem earlier this year on a 2.0 pinto..... after much worrying over possible engine faults or possible damage happening it turned out that the oil pressure switch was failing......

put a mechanical gauge on it and see if the pressure is actually dropping or not..

[Peter Bell]

Hello Trevor, what oil have you got in the engine? where abouts in Bedfordshire are you?

[Peter Bell]

Hi Trevor, was worried you used a thin modern oil but it should be good stuff. Sounds like you have a gauge too, is that electric? what pressure does that show when the light comes on? does the light come on as soon as the fan switches in? if so it must be an electrical problem.

[Guest mower man]

As Long boarder says looks as if a bottom end rebuild is on the cards,try a sender but no guarantees if a rebuild ,replace the oil pump too it's the heart of things after all HTH mower man

[johnlrichardson]

Has this just started since the head was off or since the oil was changed did you change the filter

 

jon

[Guest holmestr1972]

Has this just started since the head was off or since the oil was changed did you change the filter

 

jon

yes it has just started it had new filter and oil after rebuilt head

[johnlrichardson]

Could be the oil pressure relief valve stuck (not sure where on a crossflow) try with the old filter if you can

If your getting foaming something is causing air and oil to mix

Ill give it a bit more thought!!

 

jon

[Guest robinj66]

I might be wrong but it's possible that the fan cutting in is sapping some of your engine power causing it to rev slower (I'm reading your post and assuming that this is seen when stationary)- if your oil pressure was a bit low to begin with (Eg, because of worn bearings or pump) then the oil light comes on. When you rev it, you say the pressure comes back up which tends to support this theory.

 

If so then it's a new oil pump and/or bottom end rebuild as per Longboarder's post

[IanS]

Just started after oil change makes me think that you now have a thinner oil. E.g. was 20-50 now 5-30 at tick over this can make a lot of diferance on a slightly worn engine.

I have run old cars like this for many thousands of miles with no problems but tended to use cheeper oil to keep consumption down.

 

Other thought is missing off camshaft spray bar, I hope that this comes in teaching grandma to suck eggs realm.

 

Ian

[Guest holmestr1972]

Just started after oil change makes me think that you now have a thinner oil. E.g. was 20-50 now 5-30 at tick over this can make a lot of diferance on a slightly worn engine.

I have run old cars like this for many thousands of miles with no problems but tended to use cheeper oil to keep consumption down.

 

Other thought is missing off camshaft spray bar, I hope that this comes in teaching grandma to suck eggs realm.

 

Ian

pump ordered chaps hopefully this will fix it

thanks for the input

Trevor