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My 83 started to overheat this morning. I had topped off the anti freeze a week or so ago.. When I pulled over as the the needle kept going up I let it cool awhile and then opened the rad cap.The antifreeze was below the top compartment . I checked the oil dipstick and its full right to the line This is the 3rd time this scenario has happened this year and I have crawled underneath the car and ,examined the hoses and cant find a leak. Next I will give the cooling system a complete flush and go from there. Id'e appreciate and thought or help anyone could give.
Thanks
Norm Bailey
How many miles on the car/engine? If you're confident nothing is leaking I think a pressure test of the cooling system is next. The equipment to do that is usually available to rent (free with a deposit) from a chain parts store. Someone more familiar with 1st Gen cars could chime in, but probably take it to 15-18 psi and see if it holds.
Apologies for quoting myself, this was originally targeted for a 3rd Gen owner but most everything would likely still apply to your car...
Originally Posted by Sgtblue
A coolant seal failure is a common problem....at least in the FDs of which I'm familiar. IMO it's the price for forced induction. Boost is power. More power= more heat= more stress. NA rotarys have the problem, but AFAIK, not nearly as soon as the FDs.
Still, before doing anything, make sure you have a failed seal. Besides the 'Champagne test" these are all the symptoms I can think of... but no single symptom by itself is confirmation. Many symptoms could be from other causes. However the more symptoms/conditions you have in combination, the more likely it is a coolant seal failure.........
*Stumbling idle on cold start-up that clears up quickly. The combustion chamber is fouled with coolant. As soon as it's purged or burned up, your car will run fine until the next cold start.
*Slightly sweet exhaust smell, especially on start-up. See above. Coolant is being burned and it has a distinctive smell.
*"White smoke" (steam) on cold start-up even in warm/hot weather. See above.
*A coolant over-flow tank that is over-flowing. This will usually result in a puddle under the car near the right front...the area of the over-flow tank. When coolant gets hot it expands and that's what the overflow tank is for. But with a failed seal the natural vacuum that forms and pulls that coolant back out as the engine cools down is lost. That leaves that coolant stranded in the tank and eventually it overflows.
*Coolant loss that isn't explained by a puddle on your garage floor. It's being consumed by the engine and going out the exhaust.
*Spiking temps that seemingly recover on their own almost as quickly. Air pockets in the cooling system allow steam to form. That will cause temp spiking. This is different than a rising temp just after a period of hard boost. It can happen as your steadily cruising down the highway.
*Boiling sounds after shut down even shortly after properly "burping" the system. See above.
*Failed coolant system pressure test.
*Failed test of coolant for hydrocarbons.
*Unusually clean plugs, or wet plugs if you pull them right away after starting the car. (Sometimes you can even smell the coolant)
*One or more episodes of serious overheating in the car's history regardless of miles. (from what I've read, 115 C./240 F. seems to be the critical number for OEM seals to begin to degrade)
*An otherwise well maintained and cared-for FD approaching 100K miles or so.
As for a bandaid, some have used one of the many "Stop-Leak" coolant additives to give them a bit more time but use at your own risk. While it's not anything that will leave you on the side of the road, a failed coolant seal can lead to errosion/rust/pitting of the coolant seal grooves in the irons. That can cause a junk iron and make the inevitiable rebuild more expensive....
This morning I got the car on ramps and while underneath saw a drip coming from the back edge of the oil pan. Remember the car is on an angle on the ramps. There appears to be a half hole at the very back edge of the oil pan that the pan partialy covers.This hole comes from the block I put a welding rod up it and goes in 3/4 to 1 inch. At first it appeared to be dripping coolant, it was coolant. From there I wipped it all down and an hour later it is still dry. The RX7 is an 1983 GS with 90000 kilometers on it.We are the only owners of it and now I may put 1000 or so kilos on it a year, Its never seen winter
Sounds like a very nice car.
And the fact you found an external leak is probably a good thing, except you’ll have to wait for someone experience with the FB for more info on the likely source.
My guess is that this half-hole is the trans inspection plug that might be missing. Just guessing. Post a pic and we can tell you for sure. If this is the case, and it's a big IF without a pic, it could be a rear freeze plug going bad. Just a guess. There are also two other trans inspection plates. One at the top rear of the engine/trans and one on the passenger side just behind the exhaust header.
Sorry for the late response as Ive been away for 2 weeks. A mechanic I trust got it up on a lift and zeroed in the leak from under the intake manifold. The gasket and 2 o rings were leaking. He had to wait for parts and then the problem was gone. A complete tune up with plugs,cap,, rotor and new wires and she runs like new
Thanks for the reponses
Glad to hear that you got the issue resolved. That is a common failure point and resolving it takes a little bit of time with removing the intake manifold. But glad you were able to get the issue resolved pretty quickly!
Yep, glad it wasn't anything serious. Your mechanic probably drained and changed it in the process, but it's good to keep the coolant changed on these cars every year or so...even when they sit alot. Coolant goes acidic with time and can be hard on the soft coolant seals.
Again, it sounds like a nice car. Now go out and drive it....and don't act our age.
