ColinR

My 12a is using coolant. Since I know it is not the head gasket, Ha! Ha! Is there an easy way to distinguish between a intake manifold o-ring leak and a rotor housing o-ring leak?

trochoid

iTrader: (6)

Intake leaks occur on the intake side of the engine. Coolant can appear above or below the intake. Housing leaks rarely show externally.

djs2571

It depends how you're loosing fluid. If it's getting burned up it's on the intake side, getting sucked into the engine and 'combusted'.
If there is a loss of fluid due to overflowing it's on the combustion side, where the combustion pressure is blowing fluid out of the radiator and it's going on the ground.

Good luck.

ColinR

Yes like I said my engine is using coolant not leaking. At least I cannot see any signs of external leakage, the coolant level in my reservoir will drop approximately 1/4" after a good run. Maybe 1/2 a litre in 500km's. And my plugs are way to clean which leads me to believe the coolant is being burned off. I have not noticed tell tale white exhaust. So I was hoping to determine if it was a leak at the intake manifold or an o-ring at either rotor housing. But yes combustion pressures should be higher than coolant pressure so I should see my rad overpressuring if it was a rotor housing leak. This is what I am hoping for, less work to pull the intake than tear down the engine.
Cheers,

rwatson5651

iTrader: (5)

If the leak is on the top part of the engne then it could get sucked into the combustion chamber, could it not?

ColinR

yeah I think you are right. I am thinking piston engine where your head gasket is exposed to both combustion pressures and low intake pressure or vacuum. But the top part of the housing would only get exposed to intake pressures. hmm?

Kentetsu

If it turns out that you are "burning" coolant, here is how I fixed my issue, which was very severe: https://www.rx7club.com/1st-gen-archive-71/engine-coolant-seal-repair-maybe-750774/



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trochoid

iTrader: (6)

Not really. In order for the coolant to get sucked back into the intake, there needs to be 2 leaks, the first being the o-ring around the coolant port, the second being the intake gasket near the o-ring. A scenario that's highly unlikely.

If you think it's burning coolant, pull the lower spark plugs. If either one or both are very very clean then it's been steam cleaned by coolant in the combustion chamber. If you are burning coolant, you should see more exhaust smoke than usual. Smell the exhaust, does it have a sickly sweet smell to it?

Man_in_black49464

iTrader: (1)

dont forget to get a good look at all your hoses and clamps, if the hose is old and brittle it may just be letting enough out at its connections to the clamps.

are we forgetting something here guys????? are you loosing the fluid in your radiator, you have no resevoir you have a over flow tank it could just be evaporating the water in that overflow tank.
empty the overflow tank run it like you normally would and keep checking the radiator if it does magically displace fluid then you have a leak.

KansasCityREPU

iTrader: (9)

Another thing to look at if you think it's a bad internal water seal. When you turn the car off, do you get pressure back through the overflow hose? My engine was using water and had a bad internal water seal on the rear housing. It would suck water into the combustion camber when it was running. When it was turned off, the built up pressure would flow back though the overflow and made bubbles in the overflow bottle. I pulled the hose out of the overflow bottle and felt amd heard the pressure.