m20 oil pressure problems - please advise

[warez1]

i have an m20b27(s-eta with i top end) and the light in the dash has been flickering on and off for a while(1 or 2 weeks) today i replaced the iol bleed-off thingy and everything seemed fine until i got to the gas station... the low oil pressure light in the cluster had came on, now the thing is before this i noticed that you never knew when it was going to read low pressure, some times it was fine at idle, some times i got no pressure till 800, other times till 1,200, 1,800, 2,500 or even a few times no pressure until redline, now i dont know to much about engines but last time i checked no matter how bad the bearing are if its not making noise you are gonna make pressure as long as you are moving... the thing is, when i left the gas station the car read no oil pressure it stayed on regardless of the RPM, may it be 700 or 6,500. now its not ticking or knocking so what is going on, what do i do?

please call me and walk me thru this, its my only car - 913-636-2249

[Jordan]

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.

[Jordan]

Diagram:


Location of switch:

[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

[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]

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

[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]

could the pressure swith be getting bad contact?

[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?

[Jordan]

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

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

[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.

[warez1]

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

[Jordan]

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

Who would have ever guessed.

[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

[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.