Hello, I own a 91’ rx7 2nd gen convertible. I have been having an overheating issue in which to resolve this issue I have an upgraded thermostat, koyorad dual core radiator, oem shroud and clutch fan, larger Coolant Reservoir, and am running a denser oil, 10w 40 oil base. Where I am it’s usually 80’ and below degrees sometimes with the warmer days getting a little hotter. All belts are pulling and clutch fan is on. Started the car up today let it idle for a few minutes, barely made it 7 minutes away from my house before temp gauge maxed out. Other than a possible coolant leak is there any possible causes?

 

It could be several things, however the most simple of issues it sounds like you may still have a pocket of air trapped. I know the bleed port on the neck of the rad helps get that pocket, but I’ve also had to jack the front of the car up to get it to an even higher level the open the bleed screw. If that doesn’t seem to help i would maybe try removing the thermostat and see if that helps, (could be faulty) I wouldn’t remove it and leave it out, just remove it as a test to verify it isn’t an issue. I’m not familiar on the rotary how they act if a coolant seal goes out and starts getting combustion into the cooling system, however I feel it may act the same as a blown head gasket. So in that aspect you may be able to use a combustion leak tester on the coolant neck and see if that could be the issue. That’s about what I know to try for starters.

 

awesome thankyou, im going to look into the possible options you mentioned. I’m new to the rotary scene so I’m figuring things out as I go. it was just really weird for I installed the new radiator about a week ago and after burping it the car had been running with no issues, but I’m going to give that a try again as well and let you know

 

My guys told me the same thing. Rotary engines have a little issue with air in the coolant system after a flush or other service.
The thermostat idea is a good one, too. Might even take a look at the water temp sensor? Might be a nuisance failure. Anything that old is suspect!

 

I haven’t tried looking at the water temp sensor so I’m going to try that next thank you. I have been trying to replace old parts as they go which which is a lot considering how old the car is but I’ll keep you updated. By chance do you have any experience with water wetter? A fellow rx7 owner told me to use that with my coolant mixture as well as keep the stock clutch fan and shroud. Is that the best idea?

 

My guess is that since you already have an upgraded radiator, then the stock fan/clutch should be fine. The 'wetter' stuff seems to be for a time when
you have a working system and then add it for protection. I just looked over the product description on their web site. Has the coolant system been completely flushed recently? Got any rust in the coolant?

 

I have an '89 b2200 and the connector to the water temp sensor turned to crap, as well and the wire from it to the dash...

 

Yes water wetter is great as you can even use straight water with it, as required by race tracks.

Do you have the factory under tray under the front of the car? Without it, you’ll probably have overheating issues. It’s common, and I’ve learned it the hard way too.

Do you have a real water temperature gauge on the car? The factory s5 dash gauge is pretty much useless as it reads 3 conditions :cold, something between cold and way too hot, and way too hot. Would be good to install an aftermarket coolant temp gauge sensor pre-thermostat on the water pump housing auto get the most accurate measurement.

Is the clutch fan you have good?