wgranville

I have a 2014 ML350 with a w276 engine and I cannot seem to locate the Coolant Temperature Sensor. Does anybody know the location or happen to have a diagram for this engine that might include some insights?

chassis

From memory it is integrated into the t/stat housing. Or at the rear or one of the cylinder heads.

Maybe @S-Prihadi can comment?

wgranville

Thanks for your response! I checked the housing...not there. It could be off the cylinder head..... really tough spot to see against the firewall especially if down near the bottom. I tried a mirror but did not have any luck.

juanmor40

@S-Prihadi thread on the thermostat housing https://mbworld.org/forums/e-class-w...ml#post7781396

wgranville

Thanks for your response and the video. Unfortunately, the video is a different engine and addresses another type of issue.

juanmor40

Sorry, but it is the same engine. M276 is a unique engine with different variations in size and aspiration.

wgranville

My mistake... thanks. Checked mine and the temp sensor does not appear to be on the ther housing..... unfortunately.

juanmor40

My mistake.. I was thinking about the thermostat. As @chassis mentioned, and I think @S-Prihadi discussed in one of this thread the temperature sensor is at the back of the engine near the firewall on the engine's left side. Apparently is lower, and you may need some kind of mirror tool to see it.


Also this thread discusses related issue https://mbworld.org/forums/e-class-w...ml#post8579659

if removing it implies coolant spills over the crankshaft position sensor, that tells you everything.

here is the video for the M272 engine, yes a different engine; however, in the thread above is mentioned the location is similar

wgranville

Thanks again for sharing this info... very helpful. I believe I finally located the sensor but it appears to be protected by a heat shield. I was able to remove a torx screw from the top of the shield but I cannot get it it move or open. Any experience with this?? Picture attached.

chassis

No, that is the crankshaft position sensor. You are looking for something directly attached to the rear of the cylinder head.

@S-Prihadi have you encountered the coolant temperature sensor on your 10 year engine project?


It is at the rear of the LH side / driver's side LHD cylinder head, see photo.
https://www.ebay.com/itm/18538440719...Bk9SR-6N_pH0YQ




https://www.ebay.com/itm/33465095816...Bk9SR6LmopL0YQ


https://www.fcpeuro.com/products/mercedes-engine-coolant-temperature-sensor-mer-0999053700?ads_cmpid=352578559&ads_adid=2297821771 9&ads_matchtype=&ads_network=g&ads_creative=852283 62199&utm_term=&ads_targetid=pla-73092549984&utm_campaign=&utm_source=adwords&utm_m edium=ppc&ttv=2&gclid=Cj0KCQjwxYOiBhC9ARIsANiEIfbR q9c2VGra9snL-ILOShTnQVQOR-Ht7BqeQ0Dg5nrnigi3UKOa87waAnGgEALw_wcB

https://youtu.be/JrEF0HMoqA8

chassis

In this photo you can see the coolant temp sensor harness hidden behind the black plastic support bracket, near the torx screw.

wgranville

super helpful! similar to the heat shield.... got the bolt out of the support bracket but it does not budge or move at all.

chassis

You're into a project. The black tube and bracket needs to be removed. Look through @S-Prihadi 's posts, and he may have addressed this.

Surf ebay engine listings to get familiar with the rear of the engine and all the pieces and parts.

Remove all of the torx screws you can access, and see if you can then get to the coolant temp sensor. If not, the vacuum pump may need to come out.

I thought WIS for this is posted on this site somewhere. This W204 M272 thread shows WIS requires vacuum pump removal. I would say it's not out of the question for 3.5L M276 that the vacuum pump also needs to be removed to access the coolant temp sensor. https://mbworld.org/forums/c-class-w...c300-w204.html

WIS for M272, courtesy of Maj. Dundee may he RIP: https://mbworld.org/forums/m-class-w...ocation-2.html

This is M276, which is your engine, but it only confirms location and does not indicate removal procedure: https://mbworld.org/forums/m-class-w...s-working.html

You are looking for B11/4, coolant temperature sensor. Located in the same engine position for M272, M276, M278 and M157 (probably more engines): https://mbworld.org/forums/e-class-w...heating-2.html


https://www.ebay.com/itm/36292471393...Bk9SR-zJ4OX0YQ