Oil cooler and temp sensor

[tha881]

Evening zoners, I'm in need of some opinions on an oil temp sensor setup that includes using the original oil cooler.

20200427_192803.jpg

I've currently got this little kit installed with the 320i adaptor and cooler delete. It works nicely but its indicating that my oil temps are too high, I've seen 115 degrees on the motorway and that's using 10w40 semi. I'm wondering if having that alloy sandwich plate close to my exhaust may be heating the oil an extra few degrees?

I've been in the garage and found all the parts of my oil cooler that I removed as I'm 100% going to reinstall it. I've done a test fit and I can use the alloy sandwich plate on the oil cooler plate but it will only fit if I reverse the lines on the oil cooler and point the filter towards the front of the car, will this cause any problems?

Am I best off scrapping the sandwich plate and getting an adaptor so I can fit a temp sensor where the oil pressure switch is? What that be a more reliable option and would the temp reading at that location give much indication of oil temps? Thanks guys

[steve_k]

the best place i've found for an oil temp sensor is in a T piece with the original pressure switch & a vdo sensor as well,

you can get the T piece from the likes of demon tweeks (via ebay) for about £20 & go for the long one,

as for the oil cooler sandwich plate? i'm sorry but i have no idea about reversing the lines as when i replaced mine i used new fitting for new lines & a 13 row mocal oil cooler,

from what i can gather though reversing the lines shouldn't be a problem but i'm sure some one with mor knowledge than me can answer that one.

[tha881]

Thanks Steve, the thread size of my sensor is m12 x 150. Do you know how that would work out with the t piece pressure adaptor?

One other option is to fit it at the sump but I've heard that's not an accurate reading as the oil in the sump is in the airflow under the car.

[steve_k]

these are the fittings i used when i changed my oil cooler

https://www.ebay.co.uk/itm/AN-8-AN8-JIC ... 1289622217

two of them screwed into the block.

and 4 of these, two on the first fittings & two on the oil cooler.

https://www.ebay.co.uk/itm/AN-8-AN8-JIC ... xycmBS7l2M

& about 3 -4M of braided steel oil hose.

[steve_k]

Thanks Steve, the thread size of my sensor is m12 x 150. Do you know how that would work out with the t piece pressure adaptor?

One other option is to fit it at the sump but I've heard that's not an accurate reading as the oil in the sump is in the airflow under the car.

the T piece i used was M12x1.5 male (block side) & M12x1.5 female on the end with 2 1/8npt take off's for the extra sensors.

bear in mind i did all this a couple of years ago.

[steve_k]

fitting the temp sensor will never give a proper reading hence why i put mine in the same place as the pressure switch.

[tha881]

Thanks Steve, I'm definitely going to look for a t piece then to go in the pressure switch port, that way I can leave the oil cooler setup standard.

You're saying the pressure switch is m12x150 also? So I need one with male m12x150 and two female ports the same size?

[steve_k]

Thanks Steve, I'm definitely going to look for a t piece then to go in the pressure switch port, that way I can leave the oil cooler setup standard.

You're saying the pressure switch is m12x150 also? So I need one with male m12x150 and two female ports the same size?

no worries,

what i mean is the male end is m12 x 1.5 to screw into the block & the female end is the same to take the original pressure switch, the other holes are so you can mount the new temp switch & if wanted a pressure switch for an extra pressure gauge,

[steve_k]

You can also get a T piece with just one 1/not take off on the side.

[tha881]

I'm having trouble finding one with two m12x150 female ports. My temp sensor is m12x150, and so is the pressure switch. I may have to get one custom made or just use my temp sensor as the sump plug!

[steve_k]

I'm having trouble finding one with two m12x150 female ports. My temp sensor is m12x150, and so is the pressure switch. I may have to get one custom made or just use my temp sensor as the sump plug!

Sorry my fault.

What I meant was the port on the bottom is m12x1.5 for the factory pressure switch,

The port(s) on the side are for the 1/8npt temp sensor.

[steve_k]

Search eBay for a m12 x 1.5 T piece,

One will come up straight away.

[tha881]

Okay cheers, so conclusion is I need to find either a pressure switch or temperature sensor in 1/8 npt, or just use my temp sensor as the sump plug...

[tha881]

Some of you find this info useful if you've deleted your cooler. I replaced some of the o rings and gaskets on the oil cooler setup and got it fitted back up today. I've kept the sandwich and sensor by the oil filter. I've reversed the lines so the filter is pointing towards the front of the car, there is just enough clearance.

The oil temps are now staying around 90 degrees, although I havnt done a higher speed motorway run yet I would imagine the thermostat is opening around 90 and keeping the temperature stable.

I do think the alloy sandwich plate being near the exhaust was heating the oil above what it would have normally with just a cooler delete. And now the exhaust heat may actually be helping to warm the oil quicker, not a bad thing, as with the cooler installed its keeping the temp stable.

My conclusion is dont delete your oil cooler. Also, a sandwich plate by the oil filter may not be ideal, and I will look into moving the sensor at some point.

[DanThe]

In theory the best place for a temp sensor is where there is a constant flow of oil, the sensor will react quicker to temperature change, if its in the dead end of a T piece the oil around the sensor will take longer to warm. The exhaust manifold radiating heat could also have an influence on the sensor reading

[flybynite]

,or just use my temp sensor as the sump plug...

That is how Alpina did it, I'm not going to argue.

[tha881]

Thats good insight from you both thanks. I will move it to the sump then, if that was good enough for Alpina then it's good enough for me.

I've been out on the motorway today, at 4k rpm the temperature would not budge above 96 degrees, slightly worrying that I saw 117 degrees a few weeks ago before putting the cooler back on. I did read that semi synthetic oils were safe to around 130 degrees, but BMW obviously knew the safest temps for longevity of the engine internals. I think I've dodged a bullet with this and would advise people to keep their coolers fitted.

Am I right in thinking that by keeping the temp sensor at the oil filter, its measuring the hot oil before it enters the cooler?

[Contours]

I'm not sure of the advantage of measuring the temperature of the oil which is cooled in the sump. It would also take some time to register a reading I would imagine on the gauge and would not be indicative of the temperature of the oil circulating in the engine.

[Brianmoooore]

You want oil to be above 100 degrees to boil the water from combustion out of it.

[tha881]

I looked up the flow of oil through the engine, it goes through the cooler first, then to the filter where my sensor is located. Therefore the oil entering the cooler may well be above 100 degrees. I havnt moved the sensor to the sump yet, it will be interesting to see how the readings differ.

[flybynite]

I'm not sure of the advantage of measuring the temperature of the oil which is cooled in the sump. It would also take some time to register a reading I would imagine on the gauge and would not be indicative of the temperature of the oil circulating in the engine.

Depends on what you are using the gauge for. I use it for 2 things

1. To know when the oil is up to temperature after startup
2. To know if the oil is hotter than normal

You only know the oil is hot all through the engine when you measure it at the end of the cycle, i.e the sump.

AFAIK the oil in the filter and cooler has come from the sump and via the pump before it gets to the combustion areas of the engine.

Measuring it anywhere around the cooler or filter will be less indicative than the sump which receives the oil direct from the engine.

Mine had the oil temp sender in the sump from new and I had no problem with that end of it.

[Contours]

I am just thinking that with a sump temperature sensor, the oil in it (4 to 5 litres) has to heat up before the gauge shows a reading at all. This would take several miles for this to happen and on a very cold day where the sump is also cooled the gauge would scarcely register a reading. Could be wrong but would be interesting to know the difference in temperature between the two.

[tha881]

I have moved it to the sump and put the cooler lines back to standard, I figured that it will give the oil pump an easier time if its pumping oil down through the cooler rather than up through it.

The temp gauge was mainly fitted to see what the oil temps are reaching when on long trips, I always keep the revs low when cold and probably dont open it up properly until 30min or more of driving.

The oil in the sump may take a little longer to warm up but it's still being circulated around the engine. Unless you drive in a straight line then the oil will mix and move about going around corners.

I will update in a few days when ive had a chance to take it out.

[flybynite]

I am just thinking that with a sump temperature sensor, the oil in it (4 to 5 litres) has to heat up before the gauge shows a reading at all. This would take several miles for this to happen and on a very cold day where the sump is also cooled the gauge would scarcely register a reading. Could be wrong but would be interesting to know the difference in temperature between the two.

I don't get what you are trying to read and where you are trying to read it, and what you need to read it for?

[Contours]

I am trying to read the oil temperature in the engine and its connected to the oil filter housing. It's an indicator of when it's ok to push on when the oil warms up. Its also reassuring to know the oil is not getting too hot. The heat would be somewhat dissipated when the oil reaches the sump.

[flybynite]

I am trying to read the oil temperature in the engine and its connected to the oil filter housing. It's an indicator of when it's ok to push on when the oil warms up. Its also reassuring to know the oil is not getting too hot.

The oil at the filter is oil pumped from the sump, it then goes via the engine where it picks up the heat and ends up in the sump. You will be reading sump oil temperature at the filter anyway. Some would say it will be skewed by heat soak from the block and exhaust manifold

IMHO it does not matter where it is read or what the actual temperature reading is. You just need to know what is 'normal', when you get there and when you go over it

The heat would be somewhat dissipated when the oil reaches the sump.

You have never had oil catch your hand as you pull the sump drain out of a warmed m20 then

[tha881]

To update on this, I've moved the sensor to the sump and the readings are identical to when it was located in a sandwich plate by the oil filter, this is with the cooler fitted. Therefore, although it could be marginally slower in indicating true temp, once its upto temp it's perfectly accurate.

It would also be interesting to remove the cooler again and see if the temperatures are exceeding 110 in the sump, I have my suspicion that they wont and that the sandwich plate was being heated by the exhaust giving me higher oil temp readings.

I would advise when fitting an oil temp sensor to fit it in place of the sump plug, it's by far the easiest place to install with minimum fuss.