jdskin

iTrader: (1)

my car is overheating badly, it takes it an awful long time to warm up according to the stock temp gauge, and when Im driving it, its usually at the middle of the temp range. But the engine is getting way hotter then it should. I havent noticed the fans turning on either.

I went to kragen and told them they said it sounds like it is the water temp sensor and that is bad so it is making my temp gauge inacurate and since the gauge shows normal temp the fans arent turning on.

Does this make sense to you guys?

I cannot locate the water temp sensor from the diagram in the 94 body electric manual found of this site.

to sum it up

the fans arent working (turning on)
the temp gauge average temp while driving but takes a long time for warm up (inaccurate)
the engine was way hotter then should be

anybody know the problem?

rynberg

If you only have the stock temp gauge and it's sitting in the middle, how do you know the engine is running way too hot?

jdskin

iTrader: (1)

because after I stopped I could hear the coolant boiling

and the fans never turned on

hopefully I caught it when it started

DaveW

#1: Coolant boiling on shut-down is not unusual. With less than 50% antifreeze, and the stock fan thermoswitch (turns on at ~220F) it will definitely boil on shut-down.
#2: Slow warmup sounds like a bad thermostat (stuck partially open).
#3: As Rynberg said, you do not know the coolant temperature, since the stock gauge is so heavily center-weighted.

So:

1. You need to linearize the stock gauge, or add an aftermarket gauge to know the temperature.
2. You can lower the temperature at which the fans turn on (from ~220 to ~210F) by using the FC thermoswitch in place of the stock one.

This does not mean for sure that you don't have a problem, but the symptoms you stated are not indicative of one.

jdskin

iTrader: (1)

ok Im gonna go purchase an aftermarket thermo today and see what the temps are and if the fans will turn on Ill post my findings


thanks

Mahjik

iTrader: (1)

Also, after driving for a little bit; turn on your parking lights and let the car idle for a few minutes (i.e. 5-10 minutes after driving around town). If that doesn't kick on the fans, something might be wrong.

But, knowning the exact water temps is the kiey.

DaveW

This works because when there is an extra electrical load on the engine (i.e., parking lights) the ECU will turn the fans on at a lower temperature

BMike

If you check all the requisite fan control circuity and the fans still dont work, jiggle around each of the fan relays when the fans "should" be on and see if they kick on. I've heard of this being an issue before and my car had it, ended up that some of the stock connectors were a little melted inside and had to be rewired.

DaveW

Another pertinent comment - before I put in the Miata thermoswitch, my fans almost NEVER went on unless the AC or an electrical load was on.

jdskin

iTrader: (1)

ok that might be it then because I have not heard the fans yet but have not been using ac

is it normal for the part where you add coolant to be way hotter then the rest of the engine after about 15 min after shutting off the engine?

I think Im gonna have to order a gauge if im gonna spend 30$ for a cheap one I might as well buy a nice one.

thanks for the info davew that makes me feel a little better about the fans not running

Mahjik

iTrader: (1)

Considering his ambient temp is around mid 70's in his area, he should have no problem having the fans kick on by just letting the car run without moving (i.e. no air flowing through the radiator or oil cooler) for a few minutes after a drive.

It doesn't take much for a stock car to get to fan temp when it's not moving for a while (after it's warmed up).

DaveW

Mahjik-

I agree - I didn't mean to imply that he couldn't do what you said. That is a great suggestion.

I just wanted to point out that under normal circumstances, not having the fans go on is not necessarily a sign of a cooling problem.

Fritz Flynn

iTrader: (263)

Turn the AC on and see if the fans come on.

If they do then I would replace the thermo fan switch sensor.

If they don't check the relays and also the wires going to the fan motors on the fan assembly itself.

In 70 degree weather your fans will come on after 5 minutes of idling. If this doesn't happen your car will probably over heat in 15 minutes just idling so this could be a major problem.

alberto_mg

Yep. In case you don't know already, don't open up cooling system when its hot or warm or else you will get 3rd degree burns from the cooling bursting out. Only open the cap when the car is cold.

egauges.com has great prices and great service on lots of different gauges and gauge pods. plus you can call them on the phone and they actually answer!

Here is a great thread on installing the sensor:
https://www.rx7club.com/showthread.p...dy+coolant+tap

JyRO

iTrader: (3)

I thought I read in the stickies about the fan mod, that turning the A/C on automatically triggers the fans to go to low speed. The guy writing it said that he pulled one relay in on top of that so that when he was cruising through a parking garage, he could turn on the A/C, and the fans would come on medium speed which really kept his temps down just before parking.

I did a search to find this thread because nothing triggers my fans to come on. Just now trying to figure it out. So far I know that the 4 fin drivers side fan will come on low with 12 volts applied to the correct connectors. The 5 fin passenger side, I cannot get it to come on ... maybe that fan motor is broken. More research to come.

- JyRO

JyRO

iTrader: (3)

Scratch my last post, I was wrong.