BigDogIT

Okay I have searched the forum and found many good tips I will try to find the cause, but I have not quite seen an overheating problem like mine discribed. Hurray for being special. My 84 Rex only gets hot when I am in stop and go traffic, which is all too often in the part of California I live in. It doesn't seem to get overly warm when I let it idle, even for long periods, and never when I am flying...I mean driving at the legally posted limit...down the road. It only gets hot, sometimes to the point of steam coming out of the radiator and overflow, when I am in the stop and go traffic, it even started getting hot a couple of weeks ago when I was in the drive thru line of In and Out Burgers.

I have a new thermostat I plan on putting in this weekend, and I have changed hose from the Radiator neck to the overflow, because it was cracked, but I wonder if it could be something else. Fan clutch maybe?

What do you guys think?

Feds

Thermostat is a great start. And a new rad cap is a good idea while you are at it. Beyond that, start looking at your fan clutch. May be time to go to electric fan.

Hades12

Give your fan a spin and see how many times it goes around. Lots and it is worn out.

BigDogIT

Should I decide to replace the fan with an electric, which I am leaning towards anyway, do you have any recomendations?--brand, place to buy, so on and so forth.

Hades12

Everyone says to get a blackmagic, Summitt carrys them and has a wiring harnes also.

bliffle

This is interesting, because I notice my SE is running a little warm when I'm driving around, but it's OK to idle for a long time. Also, when I cut the engine the fan spins some more, quite freely. This suggests a wornout fan clutch.

B

Feds

Don't ask me, because I am far from stock, and none of my mods are bolt on. I'm using a fan from a 94+ cavalier/sunfire attached to a 2nd gen rad with some brackets that I made.

dirty86

i got a ford taurus fan for $20 it works great i wired it up to a switch and relay now all i need is to run it on thermostat

BigDogIT

Well I got the new thermostat in and I would say if anything it is running abit hotter. I know the stock temp gage is probably crap, but it does read a bit higher up. So the scope of what it is doing now is at speed everything runs cool as stock can be, but when I hit stop and go traffic, or even long idles like a drive thru window, the water temp goes through the roof. I think that indicates a bad fan clutch, what do you guys think?

also it seems to go through a lot of antifreeze. I think what is happening is that as the engine heats up the overflow bottle fills and then overfills. Is there anything else that could cause this?

One last thing, I figure as long as I have to take the fan off to replace the clutch I would get a better fan, where would be a good place to get an aftermarket fan and what brands/designs would you guys recommend.

thanks for the help.

Kentetsu

Go to the junkyard and spend 20 bucks on an '80s MR2 electric fan (actually 2 fans come as one unit). Then go to Autozone and spend 18 bucks on an adjustable fan control. This will run the fan only when needed. Then look in the archives for a thread titled something like "a few e-fan questions" and you will find all of the details on how to do this, including a link to the part number for the fan control and other links to pictures of my installation. This setup kicks ***, and bolts right onto the radiator in about three minutes. But most importantly, DON'T DRIVE YOUR CAR AGAIN UNTIL YOU GET THIS PROBLEM FIXED! OVERHEATING IS THE NUMBER ONE CAUSE OF ROTARY DEATH! I CAN HEAR YOUR CAR SCREAMING IN PAIN FROM HERE!!!

Kentetsu

Also, read this thread just in case this might be the true issue behind your coolant loss. https://www.rx7club.com//showthread.php?t=269544

K-Tune

iTrader: (26)

2 10" fans from your local autoparts store work very well also.

Kentetsu

Okay, I guess this thread is not in the archives (could have sworn that it was). Anyway, I did the work for you so here you go. This should be all the info that you need if you are going to convert to an electric fan (which I highly recommend). https://www.rx7club.com//showthread....-fan+questions

Kentetsu

This link has some pictures of the final installation of the MR2 E-Fan. https://www.rx7club.com//showthread....t=finally+pics

BigDogIT

Thanks for the tips everyone, I knew you would come through for me. I hope to return the favor someday. Oh and Kentetsu, those pictures you linked to closed the deal. That dual set looks sweet, and as far as I can see with your other postings that sit up will also work well when I start beasting up my Rex. Quick follow up question, I was considering running an electric fan to a blank switch spot I currently have in my dash. My Rex has ablsoutely no options which leaves me with a lot of unused spaces inside. Are there any drawbacks to setting up the fan this way? other then the obvious--I will have to manually turn the fan on when i am idling, stuck in Cali-traffic?

Thanks again!

hanman

One tidbit, make sure that you only use a Genuine Mazda thermostat. IT really does make a difference.

LinuxHead

My 84 GS doesn't have cruise, so it's got a blank cover plate where the cruise control enable
switch would go (bottom edge of the dash to the right of the column). I got a lighted rocker
switch with an outline that is just smaller than the cover plate, cut a rectangular hole in the
cover plate the size of the switch, so now I can always go back to totally stock appearance
by just scoring another plate. I put a JC Whitney adjustable thermal switch (the kind with a little
thermocouple that you can slide between fins on the radiator, or strap to the upper hose
with cable ties) at the radiator, and ran two wires back to the dash. One wire is switched and
turns the fan on manually, and the other wire goes from the fan itself to the light in the switch
(that way I get a red indicator light any tim e that the fan is running). It works good. The only
thing I would change about it is to put a relay at the radiator and have the switch controlling
the relay; right now I've got full fan current running through the switch, which doesn't feel good
even though the switch is rated for it.

cptpain

iTrader: (1)

to make it run cooler, try replacing the water pump if you havent already done so... i had the same problem and turns out when i checked the pump it was starting to cavitate

Kentetsu

As long as you have the option of having the fan work automatically with the addition of a 18 dollar part, I would never recommend that you use a switch to control the fan. It only takes one time to forget about it while sitting in the drivethrough, and your engine is toast. Do it right the first time, and your engine will thank you.

BigDogIT

Well I got the electric fan assembly from an 86 MR2. I even found the part at the first junk yard I called. Here is a tip for the masses though: before I left work on friday I went to a www.junkyarddog.com. Basically this is a search engine for nationwide junkyards. Though I luckily ended up not needing it, I had 7 emails from junk yards in my area with the part I wanted.

The Fan took a little longer to get on my radiator then I expected, but I was not anticipating my cordless drill to not work. I had to take an hour time out to go and get a new drill.

I took your advice before getting it K, and decided to go with an Autozone thermal control switch for controlling both fans. Now I don't know if the fans drew too much current, but the first switch I installed burst into flames. Smoke was everywhere and much cursing followed.

I returned that switch and installed the replacement, this one did not work at all. Not even when I bridged the senser leads together would the damn thing turn on. I now had exhausted Hollister's entire supply of thermal switches, so I picked up a toggle switch and relay assembly for those undercarriage lights the wannabe pimp mobiles all have and the thing works great. True I now have to turn on the fan everytime traffic backs up, which sucks, at least my car is not running dangerously hot anymore.

So part of my homework for today is to find a thermal control switch rated at about 50 amps to control both fans. I don't know if I actually need that kind of draw, but if one fan works okay with a 30amp relay I figure why take the chance.

So all told the whole project cost a little under $180 and that includes the $35 for the new drill.

BigDogIT

for those of you that just wanted to see if I would blow my car up, you can either stop reading now, or pay very close attention.

I installed the electric fan as discribed above, and made it to work through shitty california traffic with the needle barely going up at all. Hurray for thermal dynamics. Now my engine sounds funny. Almost, and I hate to say this out loud, like a grinding sound. I noticed it as soon as I took off the old mechanical fan and clutch assembly. Maybe I should have asked this first, but should I have left any of the old fan crap on? Or is that noise coming from the belt pully, which is where it seems to be coming from?

Kentetsu, I see by the pictures you posted you left the fan spacer on, is that for any particular reason? Supposing that those pics are of your rex of course.

I also noticed another post with pics of the e-fan setup and this person left the bolts that held the original fan spacer in place, but took the spacer out, is there a reason for this?

bottom line here do I have to but the spacer back on? the spacer bolts? take a chill pill?

Kentetsu

Well, lets see here. In one of the links I gave you concerning the installation of the MR2 fans, there will be a part number from Autozone for the fan control that I am using without issue (18 bucks). As far as the fan spacer, I left mine on because I did not have the shorter bolts needed to remove it. Did you shorten the bolts when you took yours off? Also, how did you end up dumping $180.00 into this project? My total cost was $20 for the fan, $18 for the fan control, and $2 for some wire.

BigDogIT

The $180 originally broke down like so Fan assembly from junk yard $75, $39 thermal switch from Autozone, and $35 for new drill. Of course the drill doesn't really count, and Since Hollister did not have a thermal switch that worked, I ended up with an $12 toggle and relay setup bringing the total price to $87. The only thing i can say about the fan is maybe California has less MR2's then Michigan does?

As for the spacer, well being the automotive genious that I am I just took the thing off and considered the job done. Now the project also includes a $45 water pump and a $70 engine and radiator flush.

On a positive note my rex now runs cool as a cucumber and I no longer have to drive around with the heater on. I would recommend to all those that read this thread that they replace the water pump second if changing the thermostat does not work, as that seems to have made the biggest difference with my car, and change the radiator fan with an electric third. Main reasons being though the fan replacement is really not a big job, depending on the autozone in your area having the switch you need, because I don't think the extreme cooling difference is that necesary in a stock car. Of course I don't plan on haveing much on my car remain stock, so I am glad to have the dual fans in.

Oh one other note, I only connected one fan to my hokey set up and it cools fine. I haven't decided what to do with the other fan yet.

Now to address the exhaust......

MicahMan

been there done that. i did something a little different than usual. i got a new clutch fan and mounted a eletric fan in front of my radiator. this kept my car really cool, and to top it off i built a custom hood so it let the hot air out of the top of the hood and the heat that came out of the hood actualy gave me better gas milage. lots to do with aerodynamics and the way air flows over the car.