Hi Guy's.

I have recently purchased a 94 rx7, blah blah looks nice goes well...love it!

A question for you all:

Normal driving whilst moving my car operates fine, however in traffic/city driving i'm finding the car overheating. I have read the forum and yes, i have been shutting the engine down when it starts creeping up (3/4 on the temp guage).

I realise that i need to be moving to cool the engine down, so a Koyo radiator probably wont be of much use. Can anyone suggest other ways to help me with this over heating issue whilst in traffic? (links to thermo fan mod?)

Also, how does the down pipe mod go for helping these temps?

Thanks heaps, i look forward to contributing where i can.

 

A normal car shouldn't be overheating from just sitting in traffic.

Check your coolant lines, make sure you don't have any leaks. What percentage water->coolant mixture are you running? When was the last time the cooling system was flushed?

Also, if you still have the stock pre-cat, replacing it with a downpipe will not only give you some more power but will also release some of the under-hood temps.

 

I'm not sure the last time the coolant was flushed not the mixture of the coolant. There is no leaks (i park on flat concrete).

The car only has 73,000kms (40k miles?) and a 4" stainless exhaust which i doubt would be giving heat troubles.

I guess the downpipe would also relieve my feet from sweating whilst watching the temp rise in traffic =)

I'll try giving it a flush tomorrow and see what happens. I know the rx7's run hot, so i just assumed it was a "normal" thing to be happening.

What ratio should i mix the coolant?

Thanks !

 

I would say flush the cooling system and buy a down pipe.

 

Make sure there is no air in the system. Check levels constantly. Buy new pressure caps for the AST tank and radiator. It is not normal for any car to overheat just sitting in traffic. Try putting on the heater and A/C at the same time. A/C should get your fans to kick on high and the heater will release some heat as a back up radiator =). Get the down pipe and check into the fan mod. If you can you should not drive it while it's having coolant problems.

 

i would also say when it starts to over heat turn on the a/c full blast
maybe your fans aren't coming on at all? that was my problem a loose ground wire

 

Do the fan mod. It's really easy, and it doesn't cost anything except a cheap toggle switch. You can turn the fans on and leave them on as long as you want.

When you flush the coolant, replace the thermostat with a stock mazda unit. Don't use an aftermarket one.

 

the only thing preventing u from overheating on idle is your fans they MUST kick on sooner or later to cool the temps down.

 

All the above is absolutely accurate but one other thing to check if you get a chance. When I had a similar problem, I did all the above and still had the problem. When I took out the stock rad to put in the koyo, almost half of the rad fins on the stock rad were clogged with dirt and grease. I guess just picked up over the years from daily driving. It was pretty caked in there. So, just check out the rad well. Just another .02

 

thanks for you help guys !

I'll be checking all this today and see what i come up with

 

You need to change all your fluids so you know from where you're starting. Then follow a more aggressive maintenance plan than recommeded in the Workshop Manual. It will save you a lot of money in the long run.

engine oil, tranny oil, diff oil, coolant, brake flush, etc.

Oh, adam c is right. Get a new Mazda thermostat. It's the only part you'll ever buy from Madza whose price won't make you puke.

Good luck!!!

 

hey guy's, i did as you advised.

I used a radiator flushing solution, ran that with the heater on full for around 30 mins, drained and flushed again with wather, then added high grade coolant (2.5 litres - the rest water) Burped it a few times...seems to be running fine, i left it idle for a while and it seems stable.

I checked that my thermo's are kicking in, and sure enough they are. It does help with the a/c on also (thanks for the tip).

Changed the oil, as i know oil and cooling for a rotary go hand in hand (Penrite HPR40).

Thanks again for your prompt responses !

 

holy crap, your 3/4 on the temp guage??? how many times has it does this? (I hope to god that you did not overheat your car to the point of the waterseals giving out. Usually when it starts to go up that far, your gonna get major problems soon).

why have you not bought a water temp gauge yet? the ratio i run is 80:20 water:coolant. do the fan mod (its really easy) and make sure your fans are on at least low when your car is on (unless you live in subzero conditions.)

Good luck dude!

 

yeah i got 3/4 on the temp guage only 2 times, the other times i switched the engine off once it goes a few degrees past horizontal.

The car only has 73,000 KMS on it and the engine seems fine. i did the radiator flush and im just about to install the new thermostat.

Driving withg my a/c on has helped alot, even my parking lights!

I think im going to bridge my thermo's and have them on constantly.


anyone know how to change this thermostat? I'll keep searching however..

 

I wouldn't do that, you will be only band-aiding the problem, not fixing it.

IMO, you shouldn't drive the car until you can find out exactly why it's not able to keep the temps down, otherwise you are just asking for your coolant seals to get damaged.