Okay this may be long:

My rx7 has not been overheated with this current engine, it has about 50k miles on it. I came back from a week vacation and started my car up and it started up quickly and normally then started to 1 rotor and spew white smoke, I have an exhaust leak at my downpipe and it actually sprayed a little coolant on the downpipe and I could actually rub the liquid off with my finger. It is no doubt coolant. The smoke went away in less then a minute and the car runs like normal. From that point on it has done the same thing for about 2 weeks if it sits more then a few hours. The car is not loosing any noticable amount of coolant.

I went ahead and went into diagnose mode. I pulled off the belts leading to the water pump, took the fill cap off and started the car for just about 30 seconds. A few bubbles appeared but nothing unusual for some air to be in the system.

The next day on a completly cold engine I then pressure tested the system after about an hour of sitting it had dropped from 15 psi to 13.5 psi in an hour of sitting time. I did notice some coolant sitting on top of the exhaust manifold after this, no coolant lines run by there (oil only turbo, no coolant lines in that area). But however I have not noticed coolant in this location since so I am thinking that it burns off once the system creates pressure.

It had been about a week since I did all the test and have actually driven the car a fair amount since, full tank of gas. It still starts fine, one rotors for about a minute and smokes for about a minute in the engine bay and exhaust, then runs great. In fact I had done about an hour of tuning (haltech, T70 turbo)no noticable lossof power, lost no noticable amount of coolant, did not get past normal operating temperature, however the coolant kinda smells funny. (I have a great nose)

It is a weird issue and what I think it may be is a intake manifold coolant passage leak. It in fact has a freeze plug there so no O-rings, but I have already had one freeze plug on the back of the engine corrode threw. I am thinking that this freeze plug is leaking slowly and when it sits it seeps into the intake, the car starts normally then the coolant is sucked up and smokes it all off then runs normally. Before I pull all the turbo stuff off and the intake manifold, Any recommendations of what to check next? Anything else I can do short of getting the coolant diagnosed to check the coolant seal?

Sorry its long but thought I might get some advice before I spent a sweaty sat tearing stuff apart.

 

Okay I found out a few things, First of all I forgot my engine has FD rotor housings. So there are no coolant passages in the intake. So it eliminates that possibility. I still somehow have coolant sitting on my exhaust manifold after it sits and can not figure out where its coming from.


I probably just have a blown coolant seal, just no idea why it is leaking onto the outside of the exhaust manifold when there are no hoses or coolant passages on that side of the engine.


I am stumped