Alright. So I bought yet another RX-7. It's an '88 autotragic GXL with just a hair under 76,000 miles.

The car gets pretty toasty when you drive around...but the temperature drops like a rock back to perfection the moment you stop and idle for about 30 seconds to a minute. Pretty toasty as in nearing Hell (the H). I've never let it get THAT far, but I'm not about to test it..

I did notice that the cooling system has seen some work recently. Waterpump looks fairly recent...the t-stat looks like it had been messed with recently... and the radiator is new.

Thinking it was an incorrect/malfunctioning t-stat, I removed it and filled the system back up. It ran fine and got to near temp fine. Started to drive it around and it took longer this time, but it started to heat up again. Though this time the temperature pegged out at around 1/2. Again...idling cured the issue.

Now for why I'm angry...


I hadn't looked too closely at it, but now I have and I've realized the previous owner used GARDEN HOSE as a coolant hose from the heater core on the driver's side to the rear iron! I've also noticed that it's slightly kinked right as it exits the firewall and right as it hits the rear iron. I wonder, could this be my problem? If it were kinked and allowing just enough coolant thru to keep the temps perfect at idle...but not circulating enough to cool the motor when you put it under load, wouldn't that cause what I've described? The t-stat was not a mazda unit, so I think having eliminated that until my Mazda t-stat gets here helped a bit.

 

Bingo

 

Yeah, you hit the nail on the head...that guy gets the idiot of the year award...how hard is it to go to your local auto parts store and buy some damn hose?

 

When are you coming down for another OGTA meet? The OGTA needs young people to keep the old guys from turning to dust!

 

Damn, I just replaced the garden hose with a real hose from my spare motor (The correct one)...no change.

Any ideas?

 

Any way he coulda got the belt on wrong and have the pump running backwards? Hard to do w/ a V-belt, but you never know...

 

Aftermarket thermostats are a common problem with FC's, it doesn't matter that they claim to work properly, many people have problems with them; only buy OEM. Let us know if your problem persists after you put your OEM t-stat in.

 

check that your fan clutch is working properly. Had the same problem with my 86 base.

 

Stock clutch fan? (if so, is it working? any broken fins?)
How's the rad core? Clean and clear of debris/oily crap?
Is there A/C in the car? Is the condensor clogged up?
Is there an air pump? If not, are there two belts on the water pump? (this issue can be compounded if it still has the stock clutch fan)

 

There's an e-fan that the P.O. installed. It's wired to the ignition so that it runs whether you want it to or not. Yes, it's sucking air thru the rad and not blowing it.

The waterpump is spinning the correct direction.

The radiator is new(er) and has an aluminum end tank and not a plastic one. Coolant is clean and green.

The A/C has long since leaked out all it's goods so it does not work.

I removed the non-OEM thermostat to try and rule that out as the problem, yet it still persists.

The radiator on the car has no bleeder valve so I had to do it the old fashioned way by just leaving the filler neck cap off and running the motor...squeezing hoses and whatnot. There are no bubbles or fizz which is a good sign.

Any other ideas?

A friend had suggested the timing could be too advanced. Has anyone else experienced an issue like this when their timing was off??

 

Hm, also there's no undertray...I'm working on getting another one of those as well but at such low 'neighborhood' speeds would it have that big of an impact?

 

Make sure the rad cap is building pressure. If a car's cooling system doesn't build pressure it will not run efficiently enough to cool the engine (unless you're running Evans)

You need to also put the e-fan on a switch, once you're driving over 20 mph, if that, it's hindering the flow of air more then helping.

I assume the condenser is also out of the way of the rad since you don't have A/C?? if not, yank it.

 

The rad cap states it's a 0.9 bar unit. ....same for what's on the filler neck.

 

How do I do that?

Eventually the A/C is going to be repaired, so I'm keen on keeping it.

 

Is there a good shroud on it? This would be my main suspect right there. Lord knows what that things out of or whether it pulls enough air.

And is the condensor core absolutely free of gunk? Typcially the A/C system failures are centererd around the condensor and when the system bleeds itself dry, all the oils in the system go with it. the oils get the condensor (and rad...) greasy and the dust/grime build up will effectively plug up the core.


Never in my life, and I've jacked with the timing across the board on the Haltech........EGT's will change yeah, but the car won't overheat while driving and the cool down stopped. Makes absolutely no sense it would be tied to timing.

Also, you can test the rad cap at a palce like part source. Or simply just make sure the spring holds some pressure.....crude inaccurate method but, whatever.

EDIT: Forgot to ask again, is there an air pump? If not, are there two belts on the water pump?

 

Yeah...shroud's missing. The fan is a Flex-a-Lite unit. From what I can tell it's more powerful than the clutch fan on my other FC.

Here's my plan:

-Obtain and install undertray
-Obtain and install fan shroud
-Pick up and install new Mazda thermostat
-Ask Classicauto how to clean a condenser
-Clean condenser
-Bleed/top off coolant
-Test.

-Or-

-Obtain and install new clutch fan
-Obtain and install fan shroud
-Pick up and install Mazda Thermostat
-Obtain and install undertray
-Bleed/top off coolant
-Test.
-...But still ask Classicauto how to clean condenser

 

bro i was having the same exact problem with my 1988 vert and my problem was the e-fan. it was a cheap e-fan i just recently bought a fan shroud and a clutch fan system for $40 off a used gxl and it fixed my problem. i say get a used clutch fan it should be cheap and im sure it will fix your problem. and if its not that i can guarantee it will do a better job than any efan.

 

Thanks, I'm gonna see if I can locate a clutch fan.

 

i found mine on craigslist try that man gl hope it helps

 

+1

I bet that will do it.

 

if you don't plan on running A/C I don't see why you don't just rip the Condenser and lines right out of the car.

 

I do plan on running A/C...but that is not a priority at the moment. The priority is swapping over the manual gearbox from my other car and my exhaust and my suspension. After that's done, I'll swap over my stereo system and my seats and a few other random items like the aluminum hood and sunroof panel.

Once that's completed, I will be fixing the A/C. I've got some R-12 to go in.

 

There is why he is leaving the condensor in

 

To clean the condensor or rad core, just spray on some good tough degreaser like eitehr engine degreaser or a chemical such as silicone wax remover, let it soak, and gently pressure wash the core out till there's no more gunk. Be careful not to use too much pressure as you can bend the fins pretty easily, you mostly just want to use it as an aggressive rinse.

Clutch fan suggestion is excellent....

 

You said you removed the non OEM thermostat, but did you replace it with an OEM unit or are you running without any thermostat?

Aside from that concern these guys have you on the right track.