[EvoScorp]

Hello,
I have a 2009 335i N54 with 84k miles on it. I bought it with 78k miles a year and a half ago.

While getting familiar with these engines, I always worried about oil temps. I noticed my oil temp always ran high no matter how I drove the car, it usually ranged between 230F-249F, I never saw it hit 250F but it came close many times. It has the stock oil cooler with the cooler mounted in the right wheel well. My oil temp gauge since I purchased the car always seemed to fluctuate a lot. It never got to a temp and just stuck, it would sometimes fluctuate 15-20deg up or down. I did replace the water temp sensor next to the oil filter housing and also replaced the oil level sensor in the oil pan which according to my Service manual includes the oil temp sensor. It didn't seem to change the gauge from fluctuating.

I do not beat the car, I actually drive it very conservatively 95% of the time and then occasionally do some spirited driving here and there, it is not my daily driver.

I have since performed many bolt on upgrades, Charge pipe, Tial BOV, DP, 7.5 FMIC, BMS Duel Oil Catch Cans, and am running a Stage 2 MHD tune.

I have recently replaced the Valve cover and VCG, OFH Gasket, Walnut Blasted intake, Belt Tensioners, Belt, installed the Crank Seal Guard, and am now using Liquid Moly 5W40 Molygen (The Green Stuff). I also added the ECS Tuning Low Temperature Oil Cooler Thermostat which suppose to bring the oil temps in the range of 195F-230F.

All ran great for a few months with no issues, oil temps ran pretty low, more in the lower range of this range.

But recently, I was driving in stop and go traffic and I happened to look down and saw my oil temp up around 248F-249F. It didn't go any higher but it freaked me out. It never went that high since the new thermostat was installed. I got to my destination and it sat for a few hours. When I got back in it was cooled down and I drove to my next location, in slower traffic it slowly ran back up to the high 240's again. Once I got out into open road it seemed to go down into the high 230's which is still high considering the thermostat and previous oil temps with this thermostat.

Since these incidents, I have not driven it on any trips longer than about 30 minutes but I still see the temp come up to around the 190's and hangs a bit then it slowly creeps up again and by the time I get to my destination it maybe in the mid to high 220's. I did go for a slightly longer trip once and it was creeping up into the 240's again.

So I am not sure what is going on. I have recently use the Reld's Head Gasket Tester and it came up negative. I am going to check compression this weekend possibly. I do not see any signs of burning oil, leaking oil other than my oil pan gasket which is very mild and I will be replacing it soon. The car runs fine otherwise that I can see of.

Any thoughts would be very much appreciated. If you have any questions I will try to answer as best I can. Sorry for such a long post, I tied to condense out the info as best as possible.

[autoart]

Unfortunately high oil temp. are an issue with the n54. You have to remember that there is no fan on the oil cooler, so sitting still just heats up the oil.
The ECS Tuning Low Temperature Oil Cooler Thermostat just opens at an earlier temp. then stock, that's it.
Some people say they have the same stock oil cooler and their temps. Don't go that high and others do. They often claim it is the oil they use. I have tried a couple of different oil brands and saw no difference.
A larger radiator is what seems to help the most. A larger oil cooler will also help.
MHD has an added Sport Cooling Mode, do you have that on?

[swellengear]

Your oil temps sound normal to me. Do a google, there is lots of discussion on it.

[Wolf 335]

You have perfectly normal oil temps.

N54 run hotter than other cars. Don't be alarmed and enjoy the car.

[whyzee125]

I'm very hesitant to believe people's claims of "wow my car LOVES this oil" but the switch to Motul 8100 X-cess 5w-40 lowered my oil temps significantly. Only time I've approached 250 since was once on the track and once while idling for about 30 mins in 100 degree weather.

[EvoScorp]

Thank you for your reply and information. I guess I will just drive it on a longer trip and see how things go. I guess I was just assuming since I had the cooler thermostat in I shouldn't go above 230F. And I wasn't but that was when temps outside were in the 20's-40's. Now they are in the 60's-70's.

One question would be, at what temp do you consider the oil temp too high? I did monitor my coolant temp when the oil was rising using MHD and saw that my coolant temp would range from 208F - 225F but on average be around 215F-218F. I thought about getting an aftermarket oil cooler to help temps along as well. I was looking at the Improved Racing Oil Cooler Adapter with Thermostat, it sounded like it may help.

As for the MHD sport cooling, I do not have it turned on. I could try that as well. I assume that would run the fan on the radiator? Or does it regulate the thermostat to stay open longer? Thanks again.

Originally Posted by autoart

Unfortunately high oil temp. are an issue with the n54. You have to remember that there is no fan on the oil cooler, so sitting still just heats up the oil.
The ECS Tuning Low Temperature Oil Cooler Thermostat just opens at an earlier temp. then stock, that's it.
Some people say they have the same stock oil cooler and their temps. Don't go that high and others do. They often claim it is the oil they use. I have tried a couple of different oil brands and saw no difference.
A larger radiator is what seems to help the most. A larger oil cooler will also help.
MHD has an added Sport Cooling Mode, do you have that on?

[EvoScorp]

Thank you for your feedback. I thought the oil could have been a factor as I literally just changed over to it a few weeks before this happened, so possibly it may have contributed to it as well. Prior to this I was using Liquid Moly Leichtlauf High Tech 5W-40.
As you indicated, I see a lot of people who have said they have success with different oils when it came to oil temps, would be worth a try to see if mine would be affected by something else. Maybe I will give the Motul a try. Thank you.

Originally Posted by whyzee125

I'm very hesitant to believe people's claims of "wow my car LOVES this oil" but the switch to Motul 8100 X-cess 5w-40 lowered my oil temps significantly. Only time I've approached 250 since was once on the track and once while idling for about 30 mins in 100 degree weather.

[suspect]

Originally Posted by EvoScorp

Thank you for your reply and information. I guess I will just drive it on a longer trip and see how things go. I guess I was just assuming since I had the cooler thermostat in I shouldn't go above 230F. And I wasn't but that was when temps outside were in the 20's-40's. Now they are in the 60's-70's.

One question would be, at what temp do you consider the oil temp too high? I did monitor my coolant temp when the oil was rising using MHD and saw that my coolant temp would range from 208F - 225F but on average be around 215F-218F. I thought about getting an aftermarket oil cooler to help temps along as well. I was looking at the Improved Racing Oil Cooler Adapter with Thermostat, it sounded like it may help.

As for the MHD sport cooling, I do not have it turned on. I could try that as well. I assume that would run the fan on the radiator? Or does it regulate the thermostat to stay open longer? Thanks again.

When I look in the bin file it shows a yellow warning set to 150C (302F) so I guess that would be too high. Mine gets to 121C(260F) in stop start heavy traffic. I’d worry if it was over 121 otherwise it’s normal IMO.

[335i54n]

the best thing about mhd is sport cooling, i would turn it on even stock. yeah 220 water/oil 250f is normal but not for plastics, seals, and fluid longevity. mhd sport cooling and oil thermostat bypass imo are a must, i dont care if i lose a little efficiency.

[Grease23]

My stock low mileage 328i with the N51 warms up to 230-240 every time. Your temps don't sound unusually high to me.

[dmckmc]

my 5 series N54 has a massive oil cooler with fan! Factory oil thermostat seems to open around 238 - 240F then rarely goes over 230F even when pushed a bit and summer temps. Every day driving temps stay around 220 - 225F once warmed up. Bigger car so I don't track or sport drive quite like you 135 and 335 owners though. But man the oil stays cool!

https://www.realoem.com/bmw/enUS/sho...diagId=17_0422

[suspect]

Originally Posted by dmckmc

my 5 series N54 has a massive oil cooler with fan! Factory oil thermostat seems to open around 238 - 240F then rarely goes over 230F even when pushed a bit and summer temps. Every day driving temps stay around 220 - 225F once warmed up. Bigger car so I don't track or sport drive quite like you 135 and 335 owners though. But man the oil stays cool!

https://www.realoem.com/bmw/enUS/sho...diagId=17_0422

which oil cooler and fan are you using? The realoem link shows the radiator?

[suspect]

Originally Posted by 335i54n

the best thing about mhd is sport cooling, i would turn it on even stock. yeah 220 water/oil 250f is normal but not for plastics, seals, and fluid longevity. mhd sport cooling and oil thermostat bypass imo are a must, i dont care if i lose a little efficiency.

Does MHD sport cooling impact water pump life? I read somewhere that MHD's sport cooling strategy is the same as the E92 M3 and they use same water pumps. I have also read it broke someone's water pump.

[Brandoch]

Originally Posted by suspect

Does MHD sport cooling impact water pump life? I read somewhere that MHD's sport cooling strategy is the same as the E92 M3 and they use same water pumps. I have also read it broke someone's water pump.

The E9x M3 S65 uses a mechanical belt driven water pump.

[dmckmc]

Originally Posted by suspect

which oil cooler and fan are you using? The realoem link shows the radiator?

That's the oil cooler! not the radiator - same size. Shares fan with radiator.
here is the radiator:

https://www.realoem.com/bmw/enUS/sho...diagId=17_0325

[suspect]

Originally Posted by Brandoch

The E9x M3 S65 uses a mechanical belt driven water pump.

So is it the S55 that uses the same pump?

See post 7
https://www.e90post.com/forums/showthread.php?t=2040599

[Brandoch]

Originally Posted by suspect

So is it the S55 that uses the same pump?

See post 7
https://www.e90post.com/forums/showthread.php?t=2040599

Do you always ask questions before researching?

[TheMidnightNarwhal]

Idk what to say other than I'd say 120c oil temp is fine as well. I used to often hit that and sometimes my needle goes a bit over on really hard drivings or when I did a time attack track laps. Reading online I was also surprised how some didn't get hot like mine but some others did. I just figured it was normal and seems to be because manual states 120c is still within operating range IIRC (I know manual isn't always 100% truthful either but yeah).

That said since using the MHD cooling modes did help reduce it a bit in my experience despite it being for coolant (coolant still carries heat away from the oil/block).

[TheMidnightNarwhal]

Originally Posted by suspect

So is it the S55 that uses the same pump?

See post 7
https://www.e90post.com/forums/showthread.php?t=2040599

Idk why MHD write like that. The E9X M3 do not have electric pump. They must talk about F8X M3/M4.

EDIT: Actually I have no idea anymore why they say that, no M3/M4 ever uses electric main pump after looking at parts online. They seem to only electric for auxiliary water pump.

[suspect]

Originally Posted by TheMidnightNarwhal

Idk why MHD write like that. The E9X M3 do not have electric pump. They must talk about F8X M3/M4.

EDIT: Actually I have no idea anymore why they say that, no M3/M4 ever uses electric main pump after looking at parts online. They seem to only electric for auxiliary water pump.

Yeah I checked a 2015 M3 too and it clearly states “coolant pump, mechanical” so not sure which m3/m4 MHD were talking about.

How long have you been running MHD sport cooling? Any issues? I left mine to stock cooling because of the mixed info I keep reading. In heavy traffic I usually cut the power to 90% instead. Not sure if that helps.

[TheMidnightNarwhal]

Originally Posted by suspect

Yeah I checked a 2015 M3 too and it clearly states “coolant pump, mechanical” so not sure which m3/m4 MHD were talking about.

How long have you been running MHD sport cooling? Any issues? I left mine to stock cooling because of the mixed info I keep reading. In heavy traffic I usually cut the power to 90% instead. Not sure if that helps.

I don't know really, I've had 2 cars since one was totalled so I guess about 2-3 years. No issues. But I like to deactivate it in winter time since I noticed my needle stays a bit to cold for my liking. And with it off in winter it doesn't heat as much obviously and I don't drive that aggressive obviously.

Not sure what you mean about cutting 90% power.

[suspect]

Originally Posted by TheMidnightNarwhal

I don't know really, I've had 2 cars since one was totalled so I guess about 2-3 years. No issues. But I like to deactivate it in winter time since I noticed my needle stays a bit to cold for my liking. And with it off in winter it doesn't heat as much obviously and I don't drive that aggressive obviously.

Not sure what you mean about cutting 90% power.

Good to know there’s no issues.

MHD allows you to set multiple map slots for different fuels and different power levels for the same map (stage 1 or stage2). You can set one slot for 95ron/91oct and use the slider to cut power to 90% then you can swap between these slots using your steering controls. Don’t know if it helps reduce heat though.