m20 oil pressure problems - please advise

[mops]

Oil pressure depends on viscosity and it's temperature. the thicker the oil, the higher oil pressure. the hotter the oil, the lesser pressure. aswell fresh oil gives higher pressure than worn oil (that's how you tell good oil from worn oil anyway...)

In my tired m20, i use cheap 10w40 and normally oil at warm idle is about 20 psi and if i warm it up bu abusing the engine then i'll get as low as 10 psi at idle. once warm, max pressure i get is around 55psi. but it is hard to tell exacly, id depends from oil used (different brands give different reading and respond differently to temperature), time of year and generally temperature outside, the way the car is driven, etc, etc, etc. I believe by the book minimum acceptable m20 oil pressure is 10 psi. max is 60 psi warm with max 80psi at cold start. depending on oil temp, the car will reach max oil pressure between 2 and 3k rpm (warm).

[sLEVE_11]

What is typical/normal oli pressure at idle?I have new all bearings and oil pump, oil pressure is 10 PSI 800rpm and ~18 PSI/1000rpm(hot oil).Are they pressures normally slower or OK?Oil is 10w/40 Mobil 1.My english language is veryvery bad but i hope you understand.

Nobody know?

[sLEVE_11]

10 PSI per 1000RPM is acceptabe minimum @ 200ºF oil temp.

What is typical/normal oli pressure at idle?I have new all bearings and oil pump, oil pressure is 10 PSI 800rpm and ~18 PSI/1000rpm(hot oil).Are they pressures normally slower or OK?Oil is 10w/40 Mobil 1.My english language is veryvery bad but i hope you understand.

[warez1]

Who would have ever guessed.

actually i guessed it at first... but my friend's dad(a mechanic at Baron BMW) told me that i was wrong and the it had to be the bleeder valve... also since the switch creates a ciruit to ground it can be a little confusing... the other thing is that the sensor was working wheni had it in my other car so i just figured it was cool

[Jordan]

thanks guys i swapped the switch and she is doing alot better

Who would have ever guessed.

[warez1]

thanks guys i swapped the switch and she is doing alot better

[arsevader]

The pressure switch is a big cause of hard to track down oil leaks on the M20. The plastic cracks alowing oil to seep out which then travels up the harness and deposits itself around your engine. Oil coul cause a bad contact for sure. Take a good hard look at the sensor, it's cheap.

[Jordan]

10 PSI per 1000RPM is acceptabe minimum @ 200ºF oil temp.

Colder the oil the higher the pressure is going to be.

[warez1]

also if i decide to go manual oil pressure guage what oil pressure should i be running? what at cold idle? what at warm idle, what at warm 1,500, 2,500, etc?

[warez1]

could the pressure swith be getting bad contact?

[Jordan]

Most auto parts stores can sell you a socket designed to get onto the oil pressure switch.

All it is is a deep well / thin wall socket.

[warez1]

what I want to know is why you kept driving with your oil pressure light on, and why you redlined it that way? even if it turns out to be the switch, if it had been the oil pump your engine would be screwed.

simply put, the pump has been tested, it flows great and is new

[nando]

what I want to know is why you kept driving with your oil pressure light on, and why you redlined it that way? even if it turns out to be the switch, if it had been the oil pump your engine would be screwed.

[warez1]

The first thing you should have done was replace the oil pressure switch.

The idiot light is all but useless if you do not KNOW the switch is good.

Since your engine would have seized a LONG time ago had it suffered from 100% oil starvation at redline its obvious to me the switch is bad.

i agree but the sensor is too close to the block to get a socket on it

[Jordan]

Diagram:


Location of switch: