What's up everyone? I am a bit concerned about my rx7. Lately there have been small amounts of black liquid (water/oil) coming from my exhaust when I start it up. When I let it running for 5 or so minutes, it stops. Until I rev my engine even slightly, more of this liquid gets pushed out.

I've had my car in the garage lately, so I doubt it condensation in my exhaust. I'm afraid it is the coolant seal. Again....

I did have my car sit these passed couple years. Starting it every once in a while. From what I've read, rx7 don't like to sit for a long period of time. I need some help guys. I've rebuilt my motor once before and am scared I need to do it again >_<

Any help is appreciated. Thanks in advance.

 

Combustion creates water, especially if you still have a cat on your car as the cats job is to take the hydrogen and oxygen and convert them to water so a little bit of drops being produced when running doesn't really mean much.

I would be more concerned that it is dark in color although it is most likely just carbon being expelled I would smell it and make sure it isn't oil.

If you have a coolant leak it will be released as smoke because it will be in the combustion chamber and the pressure+spark will heat it up enough for it to be vaporized.

Also, unless your garage is heated your exhaust will still have condensation in it. This is normal as well and why exhausts have a weep hole in the bottom of them so it doesn't sit in there but not all of it comes out until the car is warmed up.

 

Thanks for the input. When I do start it up, it does spew out a little buoy of white smoke. Apparently that's somewhat normal in rotaries....? Being that I didn't drive it or even start it much in the passed couple years, I topped it off with just water and whatever coolant it had in the engine from long ago.

The blackness coloration that's coming out with the water, I assuming comes from the inside of the exhaust as soot buildup from the many many years its been on the car.

I will buy/borrow a compression test pump thing sometime really soon to see whether or not pressure is being lost throughout my coolant system. That way I know for sure if it is my coolant seal or not. If it is holding its pressure, what else could be the cause of that much water being in my exhaust, other than simple condensation...?

 

It'll mostly be simple condensation. Althought what coolant mix are you running? When my car had bad seals I had 100% water in it and didn't know it blew because pure water doesn't really white smoke, coolant does however and you will know it when it does, it's a lot!!

 

Does your exhaust smell sweet?

 

It's condensation in the exhaust... The gaskets are rarely completely water tight, so you would see liquid dripping from your exhaust port area if it was liquid from the combustion chamber.

 

mahjik is correct, my fd does the same thing when i dont drive it for a while. its no problem at all, dont worry about it

 

Not sure if it smells sweet or not. It wasn't anything noticeable but I'll check it out this weekend.

I really really really hope you guys are right. Thanks for all the help!!! I'll keep you all posted.

 

In one of my previous FD, I had to put a piece cardboard behind the exhaust because in the morning, it would spit some much black water that it would get on the wall. It was black like you are describing. All it is condensation mixed with the soot in the exhaust.

 

lol...my garage door is BLACK with this crap, from when I start the car with the door shut.

As many others have said, you are fine. It's just condensation.

 

Why would you start the car with garage door close lol? To OP, like everyone said it is just water, nothing to worth about.

 

I recently pulled my fd out of storage 8 years no problem with water seals.
The best test is it consuming any Coolant? Overheating? Engine Miss?

 

Thank you all!! Everyone of you have been super helpful! I appreciate the love and care on this forum. Makes me feel like I have a whole other family I never knew about!! Much love.

As for water consumption, I'm not too sure. It's uninspected, uninsured, unregistered and I need to fix up my oil pan gasket from leaking. So obviously I haven't been able to drive it much. It doesn't overheat and the engine doesn't misfire. From what you all are saying, it sounds that I am in the clear. I will keep an eye out for anything peculiar and I'll keep this thread up to date with what I figure out soooon!!

 

Did you do anything to it before you start it up? 8 years is a long time.

 

Fuel went bad at 7th year had to replace pump, and give the fuel tank an acid bath. It took over night and many re-starts to get the injectors to function properly. Engine never did come to life until I gave the turbos a good workout on a long
curvy road.

 

Question... Running just water in my coolant system, will it evaporate into the over flow tank? Since coolant has a higher boiling temp, I was beginning to think that's why I am missing water from my coolant system. If it doesn't, it probably is sucking it through the coolant seal and blowing out of my exhaust.... :-/

I am going to flush my coolant system and fill it with just coolant. Then it should bring me a wee bit closer to finding out whether it is my coolant seal or just condensation...

 

I don't see your logic.
Leave the coolant mix as is.

 

If you have just water in there now it would be good to drain, clean and refill with a 70\30 mix or 60/40 depending on your weather. Make syre to use distilled water or just buy the 50/50 mix at the store, that works too. Many people like evans and you use no water with it but you have to order it online as far as I know.

 

be sure to use distilled water