Peter 642

My water temperature always reads zero. Figured I'd first try to clean the contacts and find the ground, then replace the temp sender.
How on earth do you get in there to do that without removing engine pieces?

Thanks.

Yarf

Try a long pair of needle nose pliers.

ernie9468

----------Or simply disconnect your J boots at the same time getting at other bite & pieces that need cleaning under there.

JohnKoaWood

Oh, also, gauge sender is the rear one.. front one (blue) is the DME temp sensor... gauge sender is 1 wire!

Peter 642

Yep; thanks. I'll give that a shot.
While I'm here, will fluid leak when you remove the (a) sender; (b) sensor; (c) both/either?

ernie9468

If you get fluid leak it will be from the (blue DME temp sensor) the other two (no) be carefull when removing the clip from the gauge sender you don't want to loose it,the one going into your air flow sensor you'll have to pull back the protector cap back in order to get at the clip,when I had my 944 every couple of years(when the car was winter store) I had taken the habit of removing both those sensors clean them out with electrical contact cleaner .Paid off in a long run since they are still on the car after 27 years & working just fine.The DME temp sensor I change once during that time.Happy wrenching & let us know how you did make out.

Peter 642

Meant to ask: Clark's says get a multiresistance potentiometer.
I've been looking and best I see is a Radio Shack volume-**** style, with no specific settings.
Where do you get a "real" potentiometer that can be dialed up or down to specific resistances?

Yarf

The radio shack potentiometer will work if the range is o to 500 or ohms.
For each temperature measurement step, connect a multi-meter across the potentiometer leads to measure the potentiometer resistance.
Rotate the potentiometer to match the required resistance.

JohnKoaWood

Same setup can be used to verify the fuel level sender wiring fron the sender to the gauge, as well as the temp sensor / cooling fan circuit and basicly any sensor on the car!

Peter 642

Disconnected the J-boot, not without minor difficulty.
I lost about 2 tablespoons (to be precise) of coolant, so there was a bit of leak.
Few questions:

1. Do I now have to bleed the system, to avoid air in the coolant system, or can I just top off?
2. I shined up my contacts on the sender and re-inserted, but in order to test, I need to get the J-boot on again, right? And if that wasn't the problem, and I need to replace the sender entirely, then I need to remove the J-boot again, right? I assume I can't trouble-shoot with the J-boot off?
3. J-boot had a bit of, well, either oil or...what? Dried gas? Let's hope not. Normal?
4. The plug attached to the connecting piece (yes, these are part names from the catalog) to the bottom of the J-boot is pretty shot; I assume simply replace? Part no. is 930 110 256 00.
5. I assume I should change all of my hose clamps, rather than try to get the old ones back on?

Thanks.