I have a mildly modified 87 TII. I had my engine rebuilt about 900 miles ago. Since I got the car back together I have been fighting overheating problems. The highest it has ever gotten is about 3/4 of the way up but, that is just too high for my likings. The guy I had rebuild the motor gave me some suggestions and I have followed them to the T. This is what I have done so far:
New water pump,
new Dual belt alternator pulley,
new Perma Cool 16" electric fan,
new Koyo radiator,
new thermastat,
runing a 30/70 mixture w/water wetter.

After doing all of this I can still go down and start up the car an let it idle with the A/C on for about 5min. and the gauge will be over 1/2 way.
I have been pulling my hair out trying to figure out the problem, any suggestions would be greatly appreciated. I just picked up a mechanical temp gauge, although I beleive the stock one is working, since once I get on the high way it goes down and when I start it takes the propper amount of time to rise.

Does anyone know of a good site with specifics on installing a temp gauge?

 

how's your timing? and is there any way you can put the stock fan/shroud back on?

where did you get that t-stat?

also, since you have an S4, installation should be fairly simple for your gauge... just drill the sender into the top of your T-stat housing... you know, the hole where there is nothing "inside".... you'll see it.

 

Thanks for the tip on the the temp gauge,
The thermostat is an oem from mazda, and I don't think I will be able to get the stock fan shroud back on. And I don't have my stock fan anymore. But I have seen people running this fan and having no problems.

 

Any chance you can take the oil cooler off and make sure that it's not gunked up somehow internally? If you've already changed your water coolant system (which it looks like you have!), your only other coolant system is the oil... Any chance one of the lines got kinked to the oil cool or something? A good "informal" test would be to run the car, and see how how the oil cooler is by hand. be careful, it should be hot

Good luck!

 

two things I would be looking at:

#1 the electric fan...it may not pull enough air or be on soon enough

#2 the electric fan wired to pull not push

 

Push comes to shove, and all else fails....Try flushing and refilling your radiator. If you filled it too quickly last time, there may be a bubble in either the lines or the pump itself. This could create a cooling problem. I've had the same happen to me before and I had to vacuum the coolant.

Rabbit

 

The oil cooler sounds like a possibility I will check it out. I think to fan is moving enough air it is pulling about 3000 cfm and it is definelty pulling. I haven't tried bleeding the coolant system I will try that too. Thanks.

 

yeah if you have not bled the cooling system you will have all sorts of problems with air bubbles boiling out and the heater core needs to be bled too. when the car is cold, pull the radiator cap. start the car and HAVE COOLANT/WATER READY. turn on the heater and stet the temp to hot, and the fan speed to full blast inside the car. let the car idle until it reaches full operating temp. then just let it sit. with the cap off, the cooling system will burp the air out through the top of the open radiator cap. when the water level gets lower, add. keep adding until it idles and holds its temp. do not turn on the A/C. While doing this, it is very important to keep checking the temp and use common sense! I am not responsible if you get your face burned off. make sure your fan is running. when it gets slightly hot, the water will start to irrupt out of the radiator in little spurts, this is what you want. those little pockets of air that trick out your guage and make hot spots are comming out. Good luck!

 

I just bled the cooling system. There was one little bubble but wasn't enough for me to add more water. I went and tested it to see if that fixed it and it didn't. Any more suggestions? I am willing to try just about anything here.

 

Did you reuse the rotor housings for the rebuild? Some of the coolant passages in those guys are pretty tiny, specifically the 2 little pair you can see through the water pump housing (top part, at the gasket), thinking maybe something either corroded to hell or got clogged with foreign material...

 

romper stomper,lol haven't seen that movie in a while! Anyways have you tried the oil cooler thing yet??? I just did the same thing to my car because is was overheating and and with the koyo, new hoses etc... my car ran perfect the only differance between our setup is that you have an electric fan and I have the stock. You may want to put the stock fan back on just to make sure.

 

Ya I suggest put the stock nack on to see what happens...

 

maybe a bad T-stat? You could try taking it out and see if you still overheat...