Please help on what is missing on 102.963 Engine W124
 

Dear all,

I have been browsing this forum for months. It's a place with so much information. Sad fact is that I don't have a garage or even a 2 ton jack to really get serious; where I came from, cars live for 10 years and get declared old enough to be exported or sold as half cut.

I have taken this picture on my engine and wonder is something missing from the plug. Seems to me like a missing Engine Temp Sensor. My question is: Is it supposed to replaced by something else or it's just plain missing and needs to be replaced. Been driving this car for 8 months now.

Thanks for now and you guys are a great bunch!

The photo is too close. Is it near the master break cylinder?

That looks like a temp sensor on the SIDE of the head by the oil filter. I've only seen them on the top.

Is there a loose plug laying around nearby?

I am working on the same type engine, from the picture it is hard to tell where you are. It looks like the oil filter and I see the injectors and it I see something that connects to the air mass chamber....there is nothing in that space on my car either, just wiring...oooohhhh damn , there a hose that connects to that plug from the rocker cover that connects to the air mass chamber and the fuel pressure regulator...well that my guess I'll have to look at mine and let you know.

Yes, it does appear to be a coolant temp. sensor with the electrical plug broken off. From experience with other engines in 124's and 201's, bear in mind that there may be more than 1 coolant temp. sensor. If your coolant temp. gauge reads normal, it may be a sensor that sends coolant temp reading to the engine module. (maybe?)

Hi all,

The picture was taken at night with a camera phone. So the contrast was pretty bad.

Yes the old filter is the black cylinder. I took the shot from the top of the air cleaner.

The 2 spade plug is on the right of the engine block; the other side is the exhaust manifold.

I could'nt find any lose plugs hanging anywhere. My temp guage is showing correct temp from 0-120 and it builds up slowly as the car warms up.

Thanks so much for the replies.

On this engine there should be 3 coolant sensors, one single wire for the temp gauge, one single wire for the ECU and a two or three wire connection sensor for the radiator fans.

Hi Rory,

Does that mean I am losing the plug for the radiator fan? Would that be the aux fan that you are referring to?

My Aux fan runs when the temp guage show >80.

That means Key in Pos 2 with engine off will hear the Aux fan roar till temp guage in instrument cluster shows <80. When this happens Viscous fan will be fully engage so that I can't turn it an inch.

My concern now is that should it be connected? or its phased out and not to be used due to some transition in engine design....

Thank you!!

Hi all,

Attached is a clearer picture taken in daylight.

Thanks

The viscous fan is not electrically operated (older models had an electrically operated magnetic clutch fan which was activated by one of the coolant sensor switches) and so only comes into action when the hot air coming from the radiator is above +- 95 deg C.

The Auxilary fan is the electric one in front of the radiator and goes on at hi speed (the roaring sound you get) if the coolant sensor is over 105 deg C. If it runs continuously then definitely the sensor you have identified is not operational and therefore the wire short circuited out somewhere.

The auxilary fan will only operate on low speed if the air conditioner is on (and only when the aircon circuit high pressure switch is activated due to thermal overload).

Both circuits are relay operated. On most of these engines all the sensors are usually situated in the front part od the engine.

Coolant sensor
 

I see what has been done, the car heater intake pipe has been removed and this sensor screwed into its place as a blanking plug.

Phto
 

This photo shows it much clearer

I agree with rorypff, your heater connection has been plugged with a sensor with the same thread pattern. The photo below shows a hose connection in the same location on a 102 engine head.

http://i179.photobucket.com/albums/w...d/HPIM4081.jpg

Wow... Thanks guys. That totally solves my mystery.

As I am in a permanent summer place, all the heater connections has been disconnected or removed when possible; And I was getting all paranoid....

Mystery solved and thanks all for your effort and time.

;)

You guys are good!