89 300e. Could someone point me in the right direction? I need to know where the following two parts are located: engine temp control sensor (I've been told rear of engine, drivers side, but I can't seem to find it) and idle control sensor. Also, does the OVP simply unplug from its harness, or is it held in by a screw or anything (on the harness end)? Thanks in advance.

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1989 300E 144K

OK. Found the Temp sensor.

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1989 300E 144K

I have a 1986 300E and the ovp on mine just unplugs.

yeah, the engine coolant temp sensor is located on the intake side at the very back (closest to the fire wall) of the head..can't miss it, it's vertical in positioning,there is nothing behind it save the firewall....the idle control valve is located on the same side of the motor but underneath the air filter assembly and directly in front of and attached to the fuel distrubutor (towards the radiator), it's horizontal in positioning....the idle control has vacumn hoses into it and an electrical connector , the coolant temp sensor only has an electrical connection, typically black and 4 pin...but I would have ask, why? I just went through this last summer on my 1990 300e....I solved the issue but I simply wonder what your symptom(s) is/are for comparison sake, you know, just for confirmation....best of luck regardless

He posted his symptoms in another thread, and they do indeed point to a temp sensor/idle control valve issue.

As for removing the idle control valve....I would replace the rubber hoses connected to it as well....which (for at least one of them, the one going to the engine) is a huuuuuuuuge pain. Have fun!

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Check it, Holmes...

300E Cold start issues

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1989 300E 144K

well, I just went out and looked at my 1990 300E to make sure and it doesn't look like your picture. My coolant temp sensor is all alone, nothing behind it nor next to it. The connecting wire and boot are susbstantial to this thing, almost spark plug bootish and wire girth in fact. As I have pulled parts off of 300es' ranging from 1988 to 1992 and they generally fit, exclusively, I would say I don't get it...maybe you have a special model with more options than do I, mine is base, pure dealer stock with no options..maybe you have heated seats or something, but mine has one giant plug to the coolant temp sensor with nothing else even remotely that impressive in the small general engine neighborhood...Holmes

The OP is double posting.
Here is an image of a M103 engine. 2.6L version. Non cat - runs unleaded or leaded. Has variable timing wheel to adjust to octane.


Here is an image of the Water temp sensor from that engine. It is in early versions and was standard in some parts of the world.


Here is the later version water temp sensor. Probably in most US versions.

interesting. Is that water temp sensor (2nd to rear) for the instrument cluster or for cis?

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Rear is CIS, second from rear is single pole sensor for cluster temp gauge.

Thank you, Thank you, Thank you! That is exactly what I need. When I pull up the parts for an 89, that green one isn't an option, so I tried an 86 and bingo!

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1989 300E 144K