This a rambling mess of a question, so I'll just put the question in bold type so you can pick it out! :D

Due to the fact that my ZZ4 L98 heads have 3/8" npt threads for temp sensors my old stock sensor won't work in the heads. So I decided to put it in the intake manifold, for that reason I put the temperature fan switch in another port in the intake. I figured that the two sensors close to each other would be pretty close to the same temperature.
Can the position of the temperature sensor in the intake manifold dramatically effect the displayed temperature? I have my old stock 1/2" temp sensor in a port on the front left (drivers-side)of the intake manifold, the temp switch for my fans is on the front right port.
The temp gauge never gets above an indicated 170 degrees. The fans are supposed to kick on at 185 and off at 175 (I think) The problem is that it seems that once the fans are on they never shut off, but the gauge never has shown anything higher than 170.
I have a Volvo temperature sensor on order from Autozone, I'm supposed to pick it up tomorrow. This is the one that is very close to the resistance of the stock sensor at 220 degrees. The Borg-Warner part number is WT510, the Wells (Autozone) Part Number is WU76.
I'm going to install this in the 3/8" port in my left head and compare the readings I get from it to the old stock one. If it I seems to work okay, I'm going to move the fan temp switch to the port on the right head.
I love my Spal fans, but I'd sure like to figure out how to get them to shut off occasionally. I think a lot of the problem is because the thermostat is a 180 degree thermostat, with the temp switch on at 185? and off at 170, the sensor never gets down low enough to shut the fans off. I guess I ought to get a 160 thermostat and see if that improves anything.

 

Interesting, Let me know what you find. :thumbs:

I used a Rayteck Infrared temp gun and measured the temp at the head location and the intake location on my ZZ4 and it was only 10 to 15 degrees difference. I put my stock sensor in the intake and do the math on the gauge. I run 170 degrees regardless of outside air temp/traffic conditions etc. so I calculate 190 degrees actual head temp. Works for me I guess???
:banghead:

 

I have my temp sensor in the port under the Upper radiator hose outlet (it barely fits), and the fan temp switch on other on the other side of the manifold. I'm not sure what the flow path out of the manifold to the radiator is, but it would seem that the water exiting the manifold would represent a good average temperture for the engine cooling system. The water flowing throught the head would be hotter, but once in the manifold it would start cooling off.
I'm going to mount the new temp sensor in the driverside head and see what sort of temperature my gauge reads from this position. According to the book I looked in the WT510/WU76 temp sensor is within 5 ohms resistance at 220 degrees with the stock sensor at 220 degrees, so it should read pretty close to the actual temp.
I'll keep you informed on what I find out.
Anyone have a part number for a temp switch that operates at a higher temperature than 185?

 

Just a thought - did you use Teflon Tape on the sensor? This is a NO-NO (guess how I know!!). This will definately screw up your sensor's output because it compromises (and can eliminate) the ground connection.

 

No tape! Just a little anti-seeze.

 

I have heard it two different ways. Some say the temp in the head is hotter since it is right by the combustion chamber. I have also heard it is hotter by the thermostat since the water in the block has been inside the head longer picking up more heat. In my opinion I really do not think it matters very much. At most the temperature should only vary by 10 degrees between the two points. I have my temp sender in the intake manifold by the thermostat. now I plan on placing the electric fan sender in the head since it is 3/8".

 

Ah yes..... One of the things learned on the "forum" last year was about our "old" temp sensors.

I drilled and retapped the temp sender hole on the head I used on the driver's side for the large sensor. So I do not have problems with my gauge not reading correct, or wondering about what sensor is "close", or where else to mount it, etc.

I left the right side at the small sensor size, and plugged it, in case I ever go to electric fans.