Last outstanding issue - Engine Temperature Sender
 

Hi Guys,

I have one last outstanding issue that is really bugging me. I need to test the oil temperature sending unit, but I am not entirely sure exactly where to find it? Is it on the right side, lower chain tensioner housing?

The temperature issue on my car is baffling me.

When I bought the car PPI said that the external thermostat was cactus as the side cooling lines and trombone cooler were not getting hot.

So I replaced the Thermostat and found one of the external side lines slightly crushed, so I replaced both of them as well.

Took the car for a drive, the temp gauge still reads around 120 after about 20 minutes, no change in temperature despite a working external cooler - the side lines were getting hot (they weren't before) and the front cooler was getting hot. (This was in moving traffic, at night with no one around in 18 C ambient temperature).

So I bought a Carrera oil cooler to be safe, and yesterday day we had a 40 C day, and my car rose to about 130 C with the Trombone (freaking me out). So we put in the Carrera oil cooler yesterday afternoon. Drove it home, again, the temperature rose to just slightly beneath 120 C, almost no change again...

The odd thing is that when I drove it in to the garage, it had been raining and the temp was about 22 C, I put my hand under to check the lines, and the send line was quite hot, but the return line was actually fairly cool (those coolers work a treat). And my gauge still read slightly below 120!!!! AARRRGGGHHHH....

I had the gauge checked when the car was completely rewired, but its like its offset by 20 C, so that it should actually read about 100 C. The only thing I haven't changed is my temp sender, so now I want to do the boiling water test.

Can there be any other reason for almost no changed in operating temperature on the car going from no external cooling, to trombone cooling to carrera cooler (sans fan at the moment) ?????

I'm at a loss as to why some people say that there gauge hardly moves off operating temperature (90 C) and some people like me go through 3 stages of cooling and see almost no change!!!! ahhahha..

You need to get a fan on the cooler. When I installed my early S cooler, without a fan the change in temperature was marginal. With the fan it general runs between 190-210.

I will be getting a fan on there ASAP, but I am at a loss to explain the 'no drop' in temperature from a non working system... to a trombone, then on to a Carrera cooler... I figured I would at least see some improvement.

However, I tested the temp sender this after noon, in 90C degree water it was showing about 109C on the gauge...

From the looks of things, my cooling system has been fine all along, its just offset by 20 degrees... and its been operating at normal temperature (which I believe is about 100 C?)....

At least that's my theory.

Now... I still am not sure if that's because the sender is a 150 degree sender. From my understanding, the sender out puts DC current depending on the temperature. I assume that the gauge interprets this and displays the reading.

For a 150 C sender, 12V = (or whatever it is) 150 C, but in a 170 Degree Gauge this would be interpreted incorrectly. But as far as I know, VDO make a 100C, 150C and 200C senders (200F, 300F and 400F)... so I don't know how that all works out.... mmmmm

It is very common for people ( along the way) to change either the gauge or the sender...and not have them as a matched pair. Talk to North Hollywood Speedometer, or others like , and get the straight answer on proper match-up of senders and gauges.

There may be no problem at all ( or maybe it's worse !)...

---Wil Ferch

I tested the sender last night using the boiling water method, the thermometer read 90C and the gauge was reading 109C....

I can't see a reason for a heating issue, sure we get hot weather but not all the time, the car is fine.

From my understanding the car is reaching normal operating temperature, around 100C and not moving from there, but the gauge is showing 120C.

Unfortunately I am not in north america so I can't ring those guys recommended for help.

it is a sender gauge mismatch for sure, I have just the opposite porblem, my gauge does not budge off 120F. I have had this problem in one of my other cars and like you pulled my hair out. How after building an entier car (race car) from the ground up could a two wire gauge be getting the better of me. I finally gave in and bought a gauge and sender set from AJUSA.com, about $65 USD, well worth it to get a workgin system.

if it helps my sender have the numbers 801/12/2 601 on it for the sender that is working in the race car, the one that gets my gauge to rise above 120F. The part number off the one which does not is 801/7/4 11 84 (out of a 1985 3.2) and on my 1988 Carrera the part number is 911.606.112.00

maybe helpful, maybe just info

Jim

Thats awesome, thanks for that I will chase it up!