While re-installing the valve cover the other day, I broke the copper contact off the sensor installed in the block adjacent to the thermostat housing. I want to replace it, but I don't know what to order. This is -not- the one that sticks out of the housing at an angle toward the right front. It's the one that is vertical, on top. It has a hex machined into it at the base, a round-bottomed groove above that (I think), and a single copper pin sticking up.

Sorry for the poor description. I should have taken a picture. A coolant temperature sensor maybe?

Oh yeah, we are talking about an 85 300SD.

Thanks,
Ray

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1985 300SD, 203,000 miles, dark blue

Lil Sarah says: "Poor old Grandma Blue Car...She's sad."

Yes, it's a coolant temp sensor. It's purpose (on my 82 anyway), is for preventing operation of the climate control blower until the coolant has reached a certain temp (something like 52C). When the coolant reaches this temp, the blower can operate, so it doesn't blow through the heater core until it's warm. That way the blower doesn't blow cold air. When it starts failing (like mine) it can start to come on too early, so it's a bit chilly when it first starts blowing.

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'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

This'd be essentially the same function on an 83 300D too right? They are both 617 turbo motors.

Now, just for the sake of asking:

What is the other one, the one that protrudes from the thermostat housing toward the radiator?

Is there more than one coolant temperature sensor?

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1985 300SD, 203,000 miles, dark blue

Lil Sarah says: "Poor old Grandma Blue Car...She's sad."

the one with the vacuum hose bibs is an ERG control device

__________________
'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

You can ground the wire that was going to the switch and it will let your heat work. i did this on my 84 300d, just leave the fan off until the engine has a little heat and it won't blow cold air.

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82 Rabbit diesel (first d), 84 Jetta turbo d (300k when sold), 83 240d (305k when sold), 84 F250 6.9d w/Banks turbo(parts truck), 86 F250 6 cyl.gasser(waiting for 6.9d), 84 300d ( 347k Sold 8/04), Y2k New Bettle TDI (185k miles), 95 740IL (wifes), 87 300TD (206k Sold 7/05), 05 Passat TDI Wagon