Hi! I recently bought my 1983 Rx7 Fb, the engine is a 12a. I have done some compression test recently and it came out pretty good, my issue is a coolant leak from somewhere. It looks like the coolant is crystallizing on top of the engine, and the coolant level is dropping.
I believe shouldn't be any internal leak as the car start fine, no bubble when the radiator cap is off, and the only white smoke that is coming out last less than a minute. Also no smell is present, which make me think of condensation given the cold weather at moment (the car is parked outside)

Can anyone help me understanding where the problem might be?

 

My first question would be why is there pink coolant in the engine? The engins is designed for the green stuff. Mazda FL22 should be what's in there.

It initially appears to be faulty o-rings between the lower intake manifold and the engine. They common my fail and coolant will puddle on the engine and intake manifold where they meet. If its excessive, it can run down and drip, forward or rearward of the engine. I suppose it could be dripping down the front iron like that when making a turn if theres a lot of coolant puddling up.

You could also see leakage from using the wiring type of coolant. Toyota's pink coolant will seep past seals and crystalize like that. It's a thinner, more slippery coolant by design. I would replace the o-rings and drain and flush the system and refill and bleed with FL22.

 

Hi! thank you for replying.

yes that's the coolant color I have on the car. I bought like that
I am step by step trying to understand all the bits and bobs. I will change the coolant asap.

Would the lower intake manifold o-ring be no.14 on this picture? Would be possible for me to change it without compromising other stuff on the engine?

I could bring it to a specialist which I have informed about this leak, but I believe the estimated cost was around £500

 

Have you checked around the thermostat housing? It could be coming from there. Sometimes the hose nipple rots away as the metal is thinner.

 

looks like that is the left side of the engine. I bet the front seal is leaking. If that is it, it isn't worth pulling and rebuilding the engine.

 

can it be fixed without pulling the engine? Do you know how it can be done?

 

No way to fix without pulling and rebuilding the engine properly. The "sandwich" design of this engine rewuires full disassembly in order to change the Coolant Sealing Rings. Avoid adding any kind of block seal compound as this will lead to blocked passages and hot spots in the engine that will cause other problems more serious than leaking a little coolant.

As the the poster states, get the riht type of coolant in there, for aluminum engine blocks. Welcome to the forum,

 

Before pulling the engine, do a pressure test on the rad with everything still attached. Only need 20 pounds of pressure.

 

thank you for replying

unfortunately this the coolant I bought it with. I will replace it asap. Do you think this will stop the leaks between the engine as well?

 

If there is coolant leaking between the rotor housings and irons, no. I would clean all of the coolant off and pressure test the system to just above cap pressure. No more than 20psi. This will cause the coolant to leak in the location or locations that it's currently seeping from.

You can also drain and flush the system and add the proper FL22 and bleed the system after replacing the intake manifold to engine o-rings and see if that solves your issue. I have personally never seen coolant seep between an ron and housing and collect on the very top of the engine. When coolant seals fail, coolant is either sucked into the engine and burned in the combustion revolution or the coolant is overheated by exhaust temps, causing overheating and excess pressure in the system that can be seen in the overflow tank. It just depends on where the seal fails or the housing corrodes.

 

thank you! I thought the same, I know it’s strange that I have frozen coolant on one side only, but if the internal seals are broken coolant should flow into the combustion chamber rather than leaking outside I guess

I shall try to change the manifold o rings and gasket first and maybe see what happens?

Should I change other gaskets somewhere else?

my last question is, would I be able to remove the manifold without screwing something else up? I have all the service manual I am willing to learn and do it myself

 

I would certainly suggest you do the intake mani gaskets/O-rings first, if for no other reason it is a far easier option than a rebuild.
I agree with others here who suggest the mani O-rings are the culprit. This is a fairly common issue on older rotary engines.
And
since you will be draining the coolant (and replacing as suggested here), I would go the extra step and
-take out the rad and get it to a quality rad shop, have them chem-dunk it in their cleaning appartus, and pressure test it
-replace ALL coolant hoses including the set that feeds the pass compartment heater...
-new T-stat and pressure cap

'Luck and welcome!
Stu A
80GS
AZ

 

I've had good luck with the two part coolant seal. You could take a chance on it before pulling the engine and doing a rebuild.

Prestone's coolant seal plugged up my original radiator.