93 RX-7
5-speed


Problem;

When I come to an idle, the coolant buzzer light goes off and the temp guage needle rises to "H." Because I'm stuck at the red light behind other cars, I hold the rpm at 1500-3000 to circulate what ever coolant I have left. The buzzer light turns off and the temp gauge needle drops back to the center. As I keep the car in motion(holding rpms or driving), the temp gauge needle stays normal. Only when I come to a stop and idle does the car begin to overheat.

After I let the car cool down, I opened the caps and noticed there is no coolant. I further investigated, and noticed coolant on the hood roof/passenger headlight cover, parallel to the reserve tank, and coolant fluids beneath the reserve tank.


Remedy;

1. I changed the thermostat.
2. Replaced the caps.
3. Changed coolant.

Situation;

Car is still overheating as described above, but the only coolant loss I can witness is when coolant is being kicked out of the reserve tank when I come to a stop. There is NO smoke coming out of my tail pipe. The car still boost fine, motor idles perfectly, just overheats at idle. Also the radiator fan comes on, evident by when I shut the car off, while the turbo timer is still on.

Suggestion please...

 

Possible clog in your coolant system??

Maybe your belts are slipping?

O-ring failure Ive heard makes your overflow tank bubble like that.

Good Luck

 

Most probably clogging or some leak...if it was an o-ring you would see a bluish white smoke from the exhaust. (if i am not mistaken)

 

Get a pressure tester pump and pump the hell out of that clog! LOL!
No, seriously, spend the bucks and get a pressure tester pump. Pump it to 16 lbs. Chances are your replacement cap only goes to 13 lbs. So pick up a 16lbs. cap while you're at it. You should be able to determine whether or not you have a coolant leak, or your 0-ring is poot. The way you test the o-ring is, if I'm not mistaken, according to Mild7, is to first determine whether or not you have a superficial hose leak. Then, if that is not the case, pump up the pressure to maximum cap pressure, let everything sit overnight. When you try to crank the motor the next morning, if the engine is flooded or the plugs are wetter than Richard Simmons at an N'SYNC concert, then your o-ring is poot.

 

Because your motor is toast.

Exhaust is being forced into the cooling jacket, this displaces coolant and then puts exhaust on the temp sensor.

Fill the car up with coolant or water. Start it when it is absolutely cold. If you see bubble after bubble coming to the top of the water neck you need a motor. Pretty simple.

 

Sounds bad, if your stock needle is moving, you could already be in trouble. This means you got the car really hot and might have warped a rotor housing, don't let this happen again. This sounds like a coolant seal to me.

FYI... when your temp gauge reads "hot" your motor is up around 260 degrees I think, and rotories don't like to be overheated.

 

Just check the neck for bubble when its COLD and start it up until thermostat opens. If there are ALOT of bubbles then time for a new motor. If not then clog or what not possible too.

 

Typical symptom of motor o-ring failure, I'm afraid...

 

****! Isn't this about the 4th o-ring failure thread today?
Damned Rotary engines!

 

After reading your replies, I'm a bit worried now...

My neighbor will lend me his pressure tester, so I'll check for clogs, leaks, etc., this weekend. The first thing I'm going to do is test for bubbles in the filler neck, wish me luck.

Do you guys think it could be due to a bad radiator? Someone told me it could be that my radiator isn't conducting heat.


Thanks for the prompt replies guys...I'll let you guys know the results as soon as I can.


115K on the clock.

 

It's 'O'ring failure.
I had the same thing, the EXACT same thing.
I did the block seal and it worked fine, I've driven about 4K miles on it and haven't had to add coolant since.
However......
The block seal doesn't work with anti-freeze. I left my block seal and water in, as the first time I did the block seal and then flushed it and put anti-freeze back in, the seal only lasted a little while. After I did it again and left the sealer and the water in it has been perfect. The suck-dog deal is now it is getting cold here, we have already had some below freezing nights (lucky my car is in a warm garage!). So I am about ready to flush the sealer and water out and put in anti-freeze again. I just don't know how long the seal will hold, maybe it is good enough now after all this time and miles that it will hold, but I am not holding my breath.
Using the block seal is a good cheap and effective "fix" until you can get a new motor. I ******* HATE this 'O' ring leaking ****.....it is such a slow death for the motor, and fixable with sealer, but unless you live in warm climes, it does limited good.

 

That coolant ealer should last you a good 10K miles.
Based on your seasonal weather.

 

More info:

http://www.scuderiaciriani.com/rx7/o-ring_failure.html

Good luck.

 

Wait until you see what the housings look like from running 100% water (if you do it for a long time). In less than a year the corrosion is so bad the housing internal webbing will corrode and break off.

 

check the hose going to the overflow tank....make sure its not pinched or quinked. A few years ago, mine did that, filled up the overflow bottle, but it was because my old PFS IC at the time was sitting on the line going from the AST to the bottle. It would let the coolant pass but when it cooled down, the vacuum wasn't strong enough to pull it back in.

Tim

 

Tim, awesome factoid. I might want to simply check this possibility tonight, as a preventive measure.

 

If I understand your question, you should check the filler neck to your reserve tank. The neck simply slots into the top of the tank and is fixed in place with a rubberized tape. With age, the tape breaks down and coolant will actually gurgle out through the seam. Solution: slather silicone sealant around the neck piece where it seats into the opening in the top of the tank, stuff it into the opening and you should be set.

 

BTW,

This particular tank is a prime candidate for an aftermarket (Moroso, etc.) expansion tank. Summit has a ton.

 

Huh?

Dood...

His O rings are fried. Toast. Vapor. History. Buh-bye.

And, unfortunately, since he's been driving it this way for a while Block Weld ain't gonna work. It only seals
small leaks if you catch them right away.

The "champagne bubble test" is the only thing you need to do to confirm this. Ever. If you have zee tiny bubbles you need zee big rebuild.

 

One other option IF you are diligent: Buy an in-line engine block heater and plug it in every night you expect it to go well below freezing (like for the next 150 nights...)

You are SO correct that as soon as you put the glycol back in the seal will fail.

I know, don't ask me how I know.

 

Leaks at the slip-fit, non-sealed neck to tank joint ( or the vent at the tank top) can easily be avoided by not overfilling the tank. Filling to 'full mark' on dip stick, cold, fills tank about 40%. At max normal temp, level rises to about 60% ... well below the vent and neck joint.

To SSR and others, these ain't buicks. When gage first rises toward red, park it, and don't drive it until you know what's wrong. Could be a simple overflow hose leak/plug as tim noted. Continued use with trips to red will boil coolant in the housings (unless npg+ is used)and toast the rubber o-rings that act as head gaskets for rotarys.

 

Not a good idea to run an engine without some form of inhibitor in the coolant. You're basically turning your engine into an electrochemical corrosion cell, the aluminium componenets will rot out in no time at all!

 

one other thing to note on the line going from the AST to the overflow tank is the line is in 2 sections. Zip tie the hoses as they go over the plastic connector just to be sure it's secure.

BTW, I just noticed how bad I butchered the english dictionary when I misspelled kinked in my post above

Tim

 

LOL! I just figured you were from some remote part of Europe or something.

 

Whats Block Weld?? Link anyone?