DIY: (E9x) M3 Thermostat Replacement

Yes, those are the correct o rings. I got lucky when I did my thermostat, my old e39 M5 used the same exact ones and I had a some left over.

kb9uwu wrote

I also had 2b59 (for months). I replaced both tstat and sensor and it was only the sensor. Buy and replace both "while you're in there."

Can you provide me with these part #'s? Did you notice any performance gains after replacing both of these parts, or did the car feel the same? I currently have the 2B59 error code.

dpilat8588 wrote

Can you provide me with these part #'s? Did you notice any performance gains after replacing both of these parts, or did the car feel the same? I currently have the 2B59 error code.

That guy sold his M and is no longer around here. I had been getting the 2B59 code intermittently for a few months and just had my thermostat replaced yesterday. My trusted indy said that, typically, if you are only getting 2B59, it's just the thermostat. If you are getting other codes with it, it can indicate issues with the sensor.

For your reference, the OEM Thermostat is part 11537836155. The OEM sensor is part 13621433076

Search ECS for either of those and they will show you the non-BMW alternatives that are much cheaper. I went with OEM for the thermostat because I bought the kit that ECS sells that came with the o-rings and jug of coolant. The kit is part 11537836155KT. The kit is only $103.

They have a non-OEM kit for $53 if you are looking to save some money.

I will not know if the thermostat alone fixes my issue since it was very intermittent. Time will tell.

I only had the thermostat error but I replaced both. The sensor was very corroded, for what it is worth. I used OEM only because I had not seen the other parts listed, and wanted them local pick-up anyway. The non-OEM is the same exact part without the BMW label, so I would have used it if I had had access to them.

Yep - I would have had the sensor replaced but forgot to order it from ECS when I ordered the kit, like a dummy

thanks for the input guys

Locksmythe wrote

I only had the thermostat error but I replaced both. The sensor was very corroded, for what it is worth. I used OEM only because I had not seen the other parts listed, and wanted them local pick-up anyway. The non-OEM is the same exact part without the BMW label, so I would have used it if I had had access to them.

do you think this thermostat DIY is easier than replacing spark plugs or pre cat O2 sensors? I have done both of those myself so I am hoping this is easier.

dpilat8588 wrote

do you think this thermostat DIY is easier than replacing spark plugs or pre cat O2 sensors? I have done both of those myself so I am hoping this is easier.

I don't think it's very difficult. I was going to do mine, but stopped short because I removed the timing chain tensioner on the right bank and it felt like it was going to cross thread going back in so I stopped and had it towed to my indy to put it back. While they did that, I just had them do the thermostat.

Have you ever removed the plenum? I had mine off in 15 mins and had never done it before. Once you get that off, the thermostat is right there and has just 3 10mm bolts to remove to get it out. There's a really good DIY video on YouTube, I think it's posted in the early pages of this thread.

gfisher99 wrote

I don't think it's very difficult. I was going to do mine, but stopped short because I removed the timing chain tensioner on the right bank and it felt like it was going to cross thread going back in so I stopped and had it towed to my indy to put it back. While they did that, I just had them do the thermostat.

Have you ever removed the plenum? I had mine off in 15 mins and had never done it before. Once you get that off, the thermostat is right there and has just 3 10mm bolts to remove to get it out. There's a really good DIY video on YouTube, I think it's posted in the early pages of this thread.

I have never removed the plenum, but it doesn't sound too bad. I am more concerned with draining the coolant and and then adding it back in and bleeding it. Is that difficult or pretty straight forward?

dpilat8588 wrote

I have never removed the plenum, but it doesn't sound too bad. I am more concerned with draining the coolant and and then adding it back in and bleeding it. Is that difficult or pretty straight forward?

syphon it out from the overflow tank. this job took me 3hrs and i have never removed the plenum prior. bleeding is easy, start the car and rev to like 2500rpms for 20 -30 secs. turn car off and loosen bleed screw, when the bubbles stop and fluid comes out tighten the screw back down. i hear this plastic screws break easy so careful. go for a quick drive to get it up to temp then purge air from screw again. you aren't draining the block so its not that complicated.

bought this kit: https://www.ecstuning.com/b-genuine-bmw-parts/thermostat-replacement-kit/11537836155kt/

and the sensor: https://www.ecstuning.com/b-genuine-bmw-parts/temperature-sensor/13621433076/

this pump to syphon: https://www.amazon.com/gp/product/B00D2QL0DU/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

nuespeedgti wrote

syphon it out from the overflow tank. this job took me 3hrs and i have never removed the plenum prior. bleeding is easy, start the car and rev to like 2500rpms for 20 -30 secs. turn car off and loosen bleed screw, when the bubbles stop and fluid comes out tighten the screw back down. i hear this plastic screws break easy so careful. go for a quick drive to get it up to temp purge air from screw again. you aren't draining the block so its not that complicated.

bought this kit: https://www.ecstuning.com/b-genuine-bmw-parts/thermostat-replacement-kit/11537836155kt/

and the sensor: https://www.ecstuning.com/b-genuine-bmw-parts/temperature-sensor/13621433076/

this pump to syphon: https://www.amazon.com/gp/product/B00D2QL0DU/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

thanks for the response. Roughly how much fluid will I be draining? Will I know when to stop removing fluid? Where is the bleed screw located?

dpilat8588 wrote

thanks for the response. Roughly how much fluid will I be draining? Will I know when to stop removing fluid? Where is the bleed screw located?

about a gallon or so from the expansion tank and then a bit more when you remove the radiator hoses from the t-stat housing. you know you're done pumping out the fluid from the expansion tank when you are just sucking air. the bleed screw is on top of the expansion tank.

nuespeedgti wrote

about a gallon or so from the expansion tank and then a bit more when you remove the radiator hoses from the t-stat housing. you know you're done pumping out the fluid from the expansion tank when you are just sucking air. the bleed screw is on top of the expansion tank.

Thanks. I ordered all the stuff yesterday. Hopefully this will be pretty straight forward.

dpilat8588 wrote

Thanks. I ordered all the stuff yesterday. Hopefully this will be pretty straight forward.

incase you haven't yet watch this but don't pull the cover off the airbox its just a waste of time/add step. video

I wanted to change my filter so I did take the cover off the airbox, but I if your filter is not due, I agree with nuespeedgti, just take out the whole airbox with filter in place and lid on tight.

nuespeedgti wrote

incase you haven't yet watch this but don't pull the cover off the airbox its just a waste of time/add step. video

I'm confused. How do you take the plenum off without taking the airbox out?

JsL wrote

I'm confused. How do you take the plenum off without taking the airbox out?

He's just saying you do not have to take the air box cover off unless you are changing your filter at the same time. You can remove the whole air box by removing the two 10mm bolts at the right side. No need to remove all of those torx on the top cover first.

JsL wrote

I'm confused. How do you take the plenum off without taking the airbox out?

gfisher99 wrote

He's just saying you do not have to take the air box cover off unless you are changing your filter at the same time. You can remove the whole air box by removing the two 10mm bolts at the right side. No need to remove all of those torx on the top cover first.

correct, do not removed the torx bolts which expose the filter, only the 10mm bolts (2).

see this thread for photos: http://www.m3post.com/forums/showthread.php?t=1273927&highlight=plenum

How similar is this DIY to a e63 M6?
My buddy has to replace his thermostat

derekc5475 wrote

How similar is this DIY to a e63 M6?
My buddy has to replace his thermostat

Two more throttle body screws?

I don't actually know but you could compare shop manuals.

Can I get away with just siphoning the coolant if I want to replace the pump as well or do I have to drain the whole thing?

Pump is much lower so you would have to drain, not syphon. Note that if you spill coolant on the belts you are supposed to change them.