M272 Engine 2006 C230 - Coolant Temp Sensor Replacement.

Alright guys, I search everywhere and don't seem to find any threads or info on this part for the M272 engine.
Doesn't seem that people are replacing this part either since there is no gauge in a return hit on the topic.

I had took the liberty of replacing this part after experiencing some issues related to this part.

Issues/symptoms:
Overheating.
LCD Screen saying visit coolant shop
Temp gauge going up and down and at times it shoots up to 100+ ringing in the alarm of overheating
Engine fan doesn't turn on
Engine fan turns on full power and doesn't turn off

What I had replace as a precaution:
Replace thermostat
Replace Coolant

Although, the thermostat looks like it starting to have issues (examining the condition after I pulled it out). The problem still persist.
I had end up replacing the Coolant temp sensor and now hope it will fix the problem.

Location of of part:
Driver side (left side) at back of engine corner next to the firewall.
This part is non reachable if you attempt to reach in. At least for my model (2006 C230) there is a oil pump installed which makes it impossible to get to. Other models that have this same engine but without the oil pump, you may be able to get to it easily.

Parts and cleaners:
1. Coolant Temp Sensor - OEM- 000-905-06-00
2. CRC - Mass Air Flow Cleaner
3. CRC - Throttle Body Cleaner
4. Crankcase Vent Valve - A2720100631 (optional)
5. Permatex® Item # 75185 - Medium Strength Blue (if you choose option #4)
6. Oil Separator - A2730100162 (if you choose option #4) <--- this bolt is remove and install reverse becareful when removing.
7. Torx 30 and ratchet
8. Towels (to wipe down the sweat) and a pack of beer or your choice of drink.

Fix:
**Drain the coolant if you want (You will need to remove the underside cover, then to the red drain port on the bottom left side (driver side)). Drain about 1/4 of a gallon. Or you can just skip this part and do swap fast to limit the amount of coolant drain when the part is remove.**
Do not attempt to get behind the firewall and the engine, despite it looks like there is room back there, there isn't. You hand can't get there nor reach it due to the oil pump. You will get your hand scratch and cut up from the metal heat shield.
1. Remove the Air Filter and bottom cover.
2. Remove the MAF and Plug (carefully put it aside). **WARNING** Do not clean this part with anything other than it's label MAF cleaner. You can consider also clean this with CRC Brand MAF cleaner since you have this out. You should watch a video of how to properly clean the MAF before attempt to clean this part.
3. Remove the downpipe elbow and the rubber hose. You can consider cleaning the downpipe with CRC Brand Throttle Body cleaner since you have this out. (Optional if you going to chase down the gunk where you pulled out the rubber hose it attached to.
4. EXTRA: Clean the Throttle body and butterfly flap as you can see it's gunked with oil and dirt. Clean with CRC Brand Throttle Body cleaner.
5. Lay on top of the engine with you center, slightly slanted with your left arm reaching in the space of the remove MAF and down pipe.
6. You will feel a plug (that is the the Position sensor. Unplug it. There is one side where you can feel and press down, then pull to loosen the plug.
7. Next to the plug you unplugged, there is a plug next to it that is next to the engine block. This is the part you are after. The coolant temp sensor.
8. Feel around it and press in a tab and pull to loosen the plug.
9. Next to the plug there is a Torx 30 bolt you need to remove which is hold down a metal collar that hold down the coolant temp sensor. Loosen Bolt and hand remove bolt. (This is the part you will need a lot of patience as you can't see where you are putting the bit to and rely on feel and guiding your torx bit to it. You don't want it to drop down the engine bay, it may be the last time you will ever touch it.) You will have a lot of swearing at this moment after you struggle getting the 2 plugs out earlier. Yes I know. This is why you would need to turn on the radio so it will muffle your swearing and the towel on the material list will come in handy by now follow by your choice of drink.

Once you got pass this point. You are almost there.
10. Get your new senor next to you. Reach in and find the old sensor and metal plate that is still on the sensor. Pull and it should just pop right out. Get your new sensor right away and plug it back into the hole. If you do this quick, you can limit the mess of coolant that is draining out on to the transmission, bottom cover and onto your floor.
11. Install the metal plate collar back on to the new sensor. Careful putting it back on since the new sensor is just lightly plugging the hole that may leak coolant.
12. Install back the bolt, hand twist until it tight and follow by the torx 30 bit to tighten it down.
13. The new sensor will seem to be turning freely, which is normal. Just have it pointed upward as it was before.
14. Install the small plug back on top of the sensor and lightly pull on the plug to make sure its locked in.
15. Install the larger plug back to the outer plug and lightly pull on the plug to make sure its locked back in.
16. OPTIONAL: Clean the downpipe, throttle body and MAF.
17. OPTIONAL: Change out the Crankcase Vent Valve and Oil Seperator.
18. Install the downpipe and rubber hose.
19. Install MAF and plug back in plug
20. Install Air Filter Cover and Lowe cover
21. Fill Coolant Reservoir with proper coolant.

Test drive to ensure the Coolant level is correct and monitor to see if temp stays normal at 85 F.

 

I have a 2006 mercedes benz c230 2.5L v6 with a 272 ... i need to replace my temp sensor cause when i stop and my car gets hot .... my fan also doesnt turn on ... can anybody tell me where that would be located ... please .... ty ... i have been searching for it for like 2 weeks now ... ty

 

 

Sounds like you may have different issues.

The worst case is you may have a bad fan or bad ecu (the one on top of the engine. As usually what they say when you bring in for diagnose by the dealership.

For me, I believe I have a bad temp sensor and bad coolant. In any case, since you have overheat issues already. Just replace all associated parts to ensure everything is new/replaced.

I would start say you should replace the following:
1. Coolant thermostat (located in center front of the engine. it's been the oil filter and the Secondary Air pump. Or just follow the hose from teh radiator to the engine, you can't miss it. You have to unlatch the hose and you will find the part to replace.
2. Temp sensor. This is located behind the engine next to the firewall on the driver side. If you are facing the engine when you open up the hood. This part is a pain to get to due to limited space between the engine and the firewall. If you have small hands, then it be eaiser, if not, you will need hours and position yourself in different position to get to it. This of course requires you to remove the intake hose and elbow. You can leave the throttle body intack. However, even with these parts removed, it's still need a lot of finessing to get this piece out. There is a bolt you have to remove to release the temp sensor. Becareful of loosing this bolt into the void, that is if you dropped it. Would be a pain to get it back and may require you to remove the bottom shield to get to it.
3. Replace coolant. Drain and Flush with new mercedes purchase coolant. Don't use Aftermarket or Autozone / off brand coolant. This is not worth the risk to save a few bucks. This is engine is very sensative to coolant and from current experience degraded coolant. Ensure when flushing the system, make sure you follow protcols to get all air out of the system or you will have heating issues to continue/lights on the dashboard.

Anyhoo, I can see you would have a lot of fun (fun as in pain) to get these parts replace. I think the easiest part to replace in this repair is the coolant. But then again, the coolant, which is special coolant which you should only buy from Mercedes dealership comes concentrated. So yea, you have to mix it with distilled water (you can get it at Walmart under a buck per gallon). Sorry, did I say it was easy, more like moderate after you go through this.

After that, your issue with the fan should operate normally. If not, then it's the more expensive fix, when may be the fan sensor (which requires the whole fan assembly to be replace) or the ecu (which requires the dealership to replace due to the programming invovled).

Best of Luck. As for me, I got it running normally without replacing the fan or ecu issues.

Here is a way to cross out if the fan had failed or not. Turn on the car, Turn on the AC and fan to full (#5 on the dial). Turn on the recirculation. This should put the engine to full AC Blast and usually kicks the fan on automatically. If the fan come on, then your fan is ok. If not, then yea, you confirm you have a bad fan assembly that needs to be replace. You should do this first before replacing the temp sensor. Unless you just want to replace it since the mileage of your car is high, it would be a good mainteance item you don't have to worry about later.

 

Oh. One more thing. This engine is very sensative to the coolant health.
If you had overheat issues, more than likely the coolant have went bad and not with specs for normal operation of the engine.
Just flush the coolant with new fluid would be ideal. Doesn't cost much and will prevent damage engine parts in the making if you ignore it.
A few jugs of coolant is usually less costly than major engine components fails due to overheat issues that comes from it.

 

Have worked on plenty 272 engines and never needed to replace a coolant sensor. Thermostats we have replaced many

 

Tyvm i appreciate it

 

Before you shoot the "parts cannon" at it like I did, check the plug and wires for corrosion at the radiator fan plug. I replaced the radiator fan, thermostat and attempted to replace the temperature sender (which by the way the dealer told me practically never goes bad) and I say attempted because is is nearly impossible to get a wrench on that torx wrench on that bolt and if you mess it up you'll wind up pulling the head to fix your problem.

I gave up and went to the dealer. Their handy dandy computer told them no voltage to the fan. They replaced the plug and bad corroded wires and I have a fan and air conditioning again.

 

Having same issues going to change thermostat and sensor as well just not sure where sensor is it’s a 2007 230sport other years are at different location from what I can tell
thanks