Coolant smoke coming from engine bay
 

Hi, I am the new owner of a 93 fd touring rx7 automatic this is my second fd ive owned. I have a issue with the car smoking coolant smoke from the passenger side of the engine bay towards the exhaust area it seems like. The coolant smell seems to come into the interior. The coolant smoke seems to disappear after I use the car for while. And no the car doesn't have coolant smoke from the exhaust. Any pointers of what it could be would be great.

sounds like a leak getting on the hot bits (turbo/exhaust). Is the level constant or do you have to add?

I'd check the turbo coolant lines first. Then the t-body coolant line going to the top of the rear iron. And I wouldn't drive the car until you find the leak.

And the reason for that is that coolant (antifreeze) can actually catch fire when it leaks onto the hot turbo.

Thanks, I meant to explain that but forgot. This might also help the OP track it down.

Attachment 605579

heater core lines run above the turbo as well and can leak.

Thanks for the advice, I still have not tracked down the leak. There isn't much room to see. The weird part is the smoke goes away after the car is driven a while. I did take it to work today. The fire possibility I never gave a thought. Scary!

Hot Temps
 

I am not sure about a fire aspect, but more that it is dangerous to drive with an unknown coolant leak that could become a sudden bigger leak and threaten your engine overheating.


I may be wrong but that coolant flow diagram seems to have the wrong direction for the flow for the throttle body lines. I thought it flowed the other way. That line is to warm the throttle body. Again I do not know, but perhaps that coolant stops flowing when the engine gets to temperature and would explain why the leak stops.


The line to the back of the block seems suspect to me. It is quite a bother to get to. If you get under the car and the coolant is dripping from the back of the engine it could be that line.


You connection at the back might be viewed by looking down past the throttle body, or by holding a shaving mirror close to the firewall at the back.


The metal nipple at the top of the throttle body often corrodes significantly and your leak could be there. You might consider plugging the line on both sides of the throttle body and see if that minimizes the problem.


That line has been entirely deleted on my car,

Back in 1994 or so, there was a recall to replace a coolant line that hardened from turbo heat, tended to leak onto the turbo, and had caused a few fires.

The diagram is correct.

I've never seen that diagram before! Thanks, Jim.

Turbo Coolant Lines
 

Thanks for the clarifications. Can you change the gaskets on the turbo coolant lines without a major re & re? Or am I confusing with the oil lines?


I guess because the system is pressurised the coolant will flow backward through the front tb line if it is disconnected from the tb. This perhaps gave me the wrong impression of the direction. I had problems all along those lines, because it seems the oem clamps just gave up; then the new worm drive hose clamps I used chewed up the old hoses.


I was also thinking the leak might be the heater pipe, and perhaps the problem stops after he turns off the heater, once the car is warm. Or is coolant always flowing in that pipe.


We had a case locally where the coolant was leaking from a crack in the turbo body itself (oh-oh). Great clouds of water vapour.

The turbo coolant hoses are rubber. No gaskets and not expensive. A key sign for changing is when they begin to swell and bloat from the heat. They can be changed in the car. Off-hand, the intake, crossover and airpump are removed.

Pressure test the system. Leaks on the passenger side are usually the turbo coolant lines, or one of the throttle body coolant hoses pooling up on top of the motor and leaking down onto the turbos. Could also be the fan switch or coolant sensor behind the thermostat.

I have been driving it the last two days with no coolant smoke. Is it possible when I jacked it up from the driver side that coolant may have spilled from somewhere onto the engine bay and it was burning it off?

Just as likely that when you jacked it up, coolant that had puddled on the engine block was drained off and the lack of smell and steam is only temporary.

IMO if you don't know the history/quality of the coolant hoses you should replace them. A set is maybe $100-120? They can all be changed in an afternoon if you have some basic tools and then you have a known quantity. The fact that you have already likely experienced a leak only makes this more urgent. If you have a small leak it can turn into a large leak in an instant and you can overheat your motor. Pull your UIM and air pump and change the hoses! Get new OEM clamps, too.

Just my .02

I'm dropping the car off at palm tree rotary and while im there install a downpipe and upgrade my temp guage Thanks for the help all

Perchance they will do a pressure test, as wisely suggested above?


If they have "smoke test" equipment for the air intake system , that might be a good thing to do sooner than later.


Are they putting in a bung for an AFR sensor?

Windshield washer hose leak.
 

I had great fun with a windshield washer hose spraying fluid all over my engine bay. Had no idea until I worked the washer with the hood open and saw a mini-geyser.


The pop-up light mechanism had severed the hose. Good idea to check that.

Update, it was the coolant feed hose to the turbo, also my precat was shot! Highly recommend palm tree rotary in porterville.

Thanks for updating. Glad you got it taken care of. And it's hard to believe there are still cars out there with a pre-cat. They can fail and damage the main cat. Replacement with a good downpipe is a 2 for 1...a reliability and performance mod.