Oil temp sensor placement

[validius]

I want to add an oil temp gauge to my 325i and i'm curious as to where people feel is the best place to place the sensor. I found this thread but its a bit of a shit show: http://www.r3vlimited.com/board/showthread.php?t=105824

The questions i'm interested in answering are:

1. What the the most relevent temp to know?
   • Oil temp entering the oil pump (pan)
   • Oil temp entering the engine from the oil cooler
   • Oil temp exiting the engine (theoretical peak)
2. Where could a sensor be best placed to provide a meaningful representation of that temp?
   • If not measuring the ideal theoretical spot, where is the balance of practical location and meaningful data?

[ahlem]

If you have room for two gauges, you can mark it coming in and exiting the oil cooler.
The oil pan temp is pretty static.
Contact these guys for good information.

http://www.longacreracing.com/products.aspx?prodid=7408

These are available from Port City Racing in Coopersville. Cool but dangerous store.

[validius]

If you have room for two gauges, you can mark it coming in and exiting the oil cooler.
The oil pan temp is pretty static.
Contact these guys for good information.

http://www.longacreracing.com/products.aspx?prodid=7408

These are available from Port City Racing in Coopersville. Cool but dangerous store.

Awesome looking gauges. I have a stockpile of VDO from my old GTI project though.

I suppose that since i'm not running any serious mods i'm not concerned about overheating the oil. Temp coming out of the cooler and going into the engine would likely be the most relevant.

[jlevie]

The stock oil cooler may not be a good place. The filter adapter has a temperature controlled valve in it and I'm not sure how hot it has to get before the valve opens. One that I played around with seemed to start opening at about 160-170F.

The oil pan may provide more appropriate readings.

It is possible to make the oil cooler operate all the time by inverting the spring and thermostat in the oil filter adapter. In which case adding a sensor to the return line from the cooler makes sense.

That said, oil temperatures on a stock M20B25 aren't an issue in my opinion unless something else is seriously wrong. I never saw temps that I'd consider seriously high on my Spec E30 under race conditions on +90F days as measured in the oil pan.

[validius]

The stock oil cooler may not be a good place. The filter adapter has a temperature controlled valve in it and I'm not sure how hot it has to get before the valve opens. One that I played around with seemed to start opening at about 160-170F.

The oil pan may provide more appropriate readings.

It is possible to make the oil cooler operate all the time by inverting the spring and thermostat in the oil filter adapter. In which case adding a sensor to the return line from the cooler makes sense.

That said, oil temperatures on a stock M20B25 aren't an issue in my opinion unless something else is seriously wrong. I never saw temps that I'd consider seriously high on my Spec E30 under race conditions on +90F days as measured in the oil pan.

Hmmm, this definitely makes me reconsider the pain of installing such a sensor. When i had one on my VW it was way easier since there was already a plugged hole meant for one on the oil filter housing. That car was my DD too so i cared about the oil being up to temp in the -15C weather before flogging the turbo.

I'l investigate drilling&tapping the oil pan bolt otherwise i just might give up.

[vpilarrt]

I installed one in my track car using a Y-block threaded into the oil pressure sensor hole. Like Jim I've never seen high temps.

[digger]

in the pan (drain plug) on a 45F morning mine took about 7mins to read 120F and stabilized at approx 160-170 after at most 20min. the engine never went over 3.5-4k

My thoughts are the more rpm and load the engine is under the temp as measured in the pan and at pressure sensor location becomes closer together. my reasoning is that under higher rpm the oil flow rate is higher and the oil pan volume gets recirculated more frequently. at low rpm it takes alot longer for the all the oil in the pan to recirculate and hence higher chance for cooling of the pan by convection.

[validius]

in the pan (drain plug) on a 45F morning mine took about 7mins to read 120F and stabilized at approx 160-170 after at most 20min. the engine never went over 3.5-4k

My thoughts are the more rpm and load the engine is under the temp as measured in the pan and at pressure sensor location becomes closer together. my reasoning is that under higher rpm the oil flow rate is higher and the oil pan volume gets recirculated more frequently. at low rpm it takes alot longer for the all the oil in the pan to recirculate and hence higher chance for cooling of the pan by convection.

In your opinion, is the stock oil cooling system more than adequate? Oil temp would be one of those interesting to know but in no way required sort of items?

[redlightpete]

I was keeping an eye on my oil cooler after some front end damage, and it was never obvious that there was any oil circulating through it, even at track days. So as Jlevie notes, this wouldn't be an appropriate location.

[digger]

In your opinion, is the stock oil cooling system more than adequate? Oil temp would be one of those interesting to know but in no way required sort of items?

on the street yes, on the track dunno, as i've no data personally. others have said its not an issue