rotary engine problem!
 

I have had my 2004RX8 for around 6 months, and now I have a problem causing it to be unusable!

Hopefully someone here with more knowledge than me can help me diagnose the problem…

The story goes as follows, driving home, no problems, then all of a sudden the pipe gets blown off the top of the rad, causing water & steam to flood out, overheat and die!

This was repaired and as soon as the car was started again the same problem happened again, the same joint went. It was joined very well, it was defiantly a unusual amount of pressure build up that caused the problem, not a weak repair.

When turning the car over with out the expansion lid on, the water is literally pumped out, which in my opinion would point towards a head gasket on a usual engine, but I have very little rotary experience, and realise that there is no head gasket!

What would be your opinion on the fault, any help is greatly appreciated, as im off the road at the moment!

Should I consider replacing the engine? Also it struggles with hot starts is that’s relevant. Recently changed leads, coil packs, spark plugs, oil.

Thanks in advance.

the pipe at top of the rad? I assume you mean you are using stock radiator and the top small short plastic nipple "broke"

usually it will not just "blown" off, What I'm trying to say is someone broke it before you, glue(joined?) it back, sell the car to you.

you will not be able to "joined" that part back together no matter how good the glue you use. no glue can handle 100 Celsius and coolant chemical for too long.

Only thing you can do is replace the Radiator. Try not to replace it with another stock unless you have no choice.

There are options out there, like Koyo, BHR, Mazmart, etc etc.

ONE THING to Remember is that you MUST transfer the foam sealing piece from the stock rad to your new Rad. other wise your car will overheat

Also, you should replace your Thermostat at the same time as Radiator Replacement.

No point replacing the engine, you should replace the radiator and thermostat first.

By this do you mean that the engine overheated and died? Could be catastrophic if so.

Hi, thanks for your replies,

Nycgps: Yes the radiator nipple has been broken before hand and repaired using glue. I have driven 1000’s of miles like this without a problem, so are you sure its because of the weak join? Is it usual for the coolant system to become so pressurized?

Godesshunter: No the car didn’t overheat causing it to die, I put that across wrongly, what I meant by this was, as there was no water cooling the engine it would consequently overheat. The car was stopped as soon as possible!

I have spoken to a couple of mechanics without any specific rotary engine experience who seem to think carbon build up may have caused the seals to have became stuck open, is this possible?

Thanks again.

yeah you cant repair it like that and expect it to last. replace.

It does sound as if you have engine coolant seal damage. The statement that water is pumping out of the expansion tank when the engine is being turned over sounds like game over.

Where are you? Country, State? I'm just wondering to what extent I may be able to help you.

Paul.

Cooling system is always pressurized on any car so it will raise the boiling point, cuz anything boiling is not cool to the engine.

1000s of miles? you got lucky that's all. now I think you will have to face the consequence

This is what happens when you go cheap or think you are so smart that you fixed it with a 5 dollar epoxy. there are things that you are not supposed to try to fix it, replacement is your only choice.

not thing to talk shit but, what you can do now is fix it properly this time by telling Mazmart above me your location, he can hook you up with any Mazda (even aftermarket radiator) parts and he can beat any, I mean "ANY" dealership prices on genuine Mazda parts.

I'm in the UK. Thanks for your advice, ill start with a new radiator, and see where I stand.

As Paul stated, this does not sound like normal coolant pressure build-up from heat/expansion. It does sound like a coolant seal is blown, resulting in combustion gasses overpressurizing the cooling system.

Rather than start with a new radiator, which would be a waste of money and effort if there is a blown seal, start with a compression test and cooling system leakdown test.

He needs a new radiator regardless of what the engine condition is.

Just change the rad first, then pressure test the cooling system, that's probably the easiest way right now.

I have a mechanic relative that is willing to help me, is this a task that he is able to take on where do I purchase the seals? Is there a guide to replacing them? How much time is it likely to take?


thanks

I am by no means the authority of the internals of this engine, however, based on what I have read on this forum, sounds like the motor needs to be rebuilt. You can not simply change the seals in question and throw it back together. Another motor or a rebuild is in your future. If I am wrong, I am sure someone will chime in.

i think you're correct, its not a head gasket, but a water seal, exactly the same thing. engine needs to be rebuilt/replaced