Guitarplayer107

Hello everyone. To start things off, I do not know much about RX8s or Rotary Engines. I have 5 years of experience with automechanics and even have a technical degree in the field. I just recently purchased an 2005 RX8 Shinka Edition, and at first, only had starting problems. I was driving to the mall one day, and a cloud of white smoke burst out from under my hood. I pulled into the next gas station, popped the hood and found that my Resvoir tank cap had popped off, cracking the resevoir tank. I had the shinka towed to an experienced auto mechanic, and after running diagnostics, they are unsure of what could be causing the excessive coolant pressure, causing my cap to blow off. So I had the car towed back to my apartment. I replaced the thermostat, the resevoir tank, the coolant cap, radiator hoses and the coolant temperature sensor. I'm still having the excessive pressure build up, causing my cap to "hiss", and making my car sound like it's crying. And, now each time I start up my car to test the pressure, my car's exhaust emitts thick white smoke. What could be the cause of this?

200.mph

iTrader: (9)

sounds like a coolant seal. do a leak down test to check if exhaust gas is present in your coolant bottle. you can also leave the cap off start the car and see if the coolant is bubbling

Guitarplayer107

Alright. Thank you. And if the coolant does happen to be bubbling when starting the 8 with the cap off, what would be the fix for that? The coolant seal?

kevinande

If it is a coolant seal, unfortunately rebuild time...no way around it

200.mph

iTrader: (9)

if thats the problem its rebuild time. i would do more testing before going that route tho.

Guitarplayer107

So the coolant seal is not replaceable? It requires a whole new engine? And what all tests can I do in hopes of disproving a bad coolant seal?

RIWWP

iTrader: (2)

The coolant should be tested for combustion gasses and the oil should be tested for coolant. If both tests are negative, then you almost certainly don't have a coolant seal failure. Technically, one is still possible without either contamination, but it's a very narrow set of circumstances.

The coolant seals are inside the engine, and the engine has to be removed and disassembled to get to them, which means by definition the engine has to be rebuilt to replace them.



Read through my thread here: https://www.rx8club.com/trouble-shoo...eating-236766/
I ended up replacing everything to solve my problem when I was dealing with constant overflow problems. I suspect it was a clogged radiator.

200.mph

iTrader: (9)

op, where are you located? i had a similar issue last spring after a coolant flush and it turned out to be debris clogged up in the brass restrictor in a coolant line during the flush

Mr.Mango

iTrader: (2)

Think of it like a blown headgasket... Your getting bubbles when running and high pressure magically appearing from inside the system. I would say coolant seal.. But to prove 200.mph's threory wrong do a flush then recheck.

Very unlikely he would have coolant in his oil, as the oil is a much higher pressure system. He might have milky coolant if that was the case but from the sounds of his problem its entering the housing. Not saying he couldnt have coolant in his oil but less likely, oil change would be needed as coolant would sit under oil.

RIWWP

iTrader: (2)

Actually for the rotary, coolant shows up in the oil more readily than combustion gases show up in the coolant. The oil test has been used to diagnose a failed coolant seal quite frequently. Whether the coolant gets there during decel, combustion, or with the car off, it certainly does get there.