Whats is the operating temperature of the coolant supposed to be?

150F to 190F?

 

180F Is the stock T-stat temperature.

 

K, what is the thermo sensor used for usually?

 

theres several in the FC. One is used for the ECU to get its temp reading which allows for fuel map adjustment based on engine temp, one other one is for your gauge (or both, haven't figured it out yet) and another is for the cold start assist.

 

The one on the filler neck of an S4, just on top of the water pump. What is it used for that particular one....

And when you do a S4 J-spec swap with USDM Harness...where does it plug in? Any of you guys have any pics?

Oh, and thanks Classic, you're the ****.

 

"The one on the filler neck of an S4, just on top of the water pump. What is it used for that particular one...."

That's the one for the ECU.

BTW, the tiny one (one-wire) below the oil filter is the coolant temp sender for the coolant temp gauge, the fat one beside it is the oil pressure sender (one-wire, weird clip)

 

Actually the one on top of the water pump is for something else...thats the one I'm not 100% on. The one on the back of the water pump housing (green plug) is for the ECU. The little guy on top I'm not sure about.

It may have something to do with the gauge, might be somethign to do with cold start. Not sure. Sorry, oh and thanks

 

I'm silly, didn't read right there....the one on top of the thermostat controls the electric fan, usually on automatics I believe... a thermo switch of some sort...

Just remembered...the cold start assist uses the oil temp sensor (one-wire) mounted on the side of the oil pan

 

Oil temp sensor? You sure you want to go with that answer?

 

Oh snap!


I'd belive thermo switch...I wasn't sure which was which when I did my Haltech install, so I hooked both that one, and the one beside the oil pressure sender back up. My gauge still works so.... A simple multi meter test will tell if its a switch though, and it probably is.

 

O.K. Wrong wording...I should have said "sub-zero assist"

The Little bottle mounted on the passenger side (left hand drive) firewall that you fill with 90% antifreeze and 10% water uses the oil thermo sensor on the oil pan (one wire sensor). When the temps. are below around -4F to -10F (-20C to -12C) as per the FSM, this mixture is squirted into the intake manifold. This is in non-california cars only.

I'm still sticking to what I said in post #8, though!

Also, I know the sensor mounted on top of the thermostat cover is for the fan because on a friends car the fan kicked on when it was unplugged. The sensor to the left of the oil pressure sender is the sender for the coolant temp gauge.

Let me know if this makes sense or whether I need another coffee.

 

Which system does the sensor on the bottom of the radiator correspond to?

 

so the one-wire plug on the drivers side of the oil pan, all the way to the front, is an oil temp sensor? i thought it was for the oil level and corresponded to one of the warning lights, altho im not positive on this

 

Yes, its an oil level sender. Puts a light (and a buzzer?)on when the oil is getting low.

 

Two sensors on the bottom of the oil pan (on non-california cars?)...the one-wire is oil temp for sub-zero system, the two-wire is oil level sensor.

the one at the bottom of the rad is a coolant switch, closed above around 15 degrees celsius. It affects how the secondary air injection control system sends air from the air pump. See pages 4A-45 and 46 in the FSM (1988).

 

The thermosensor on the back of the water pump is for the ECU, used mostly to add more fuel when the engine is cold. The sensor on the rear plate under the oil filter is for the temp gauge.

Temp switch for the auxiliary e-fan in front of the radiator. It turns the fan on if coolant temp reaches 207degF.

Same place as before.

Well he should because he's right. If you're going to be that cocky it pays to check you info before posting...

It amazes me how long it takes to get the right info into these threads. Lot's of guesses, mostly wrong, despite how easy all this is to find in the FSM. Surely if you can read a forum you can read the FSM...

 

Eh, thought he was talking about the oil level sensor.

 

Where's the oil temperature sensor in an FC? We actually have one? News to me.

 

Me too. It is indeed on page 2-8 of the FSM though. Guess I never payed enough attention?

 

As already mentioned, there's an oil temp switch in the sump to activate the sub-zero start assist system.