Bad Coolant Seals? Something else?
 

I bought my first rx7, a GSL-SE, one month ago, and it has always had a lot of white smoke at startup. I live in a humid climate and my other cars often put out a lot of "smoke" when I first start them this time of year, which I guess is just water vapor from the exhaust. However... I noticed I am loosing coolant in the rx7. Every few days, the reservoir is down at the "low" level again. It only smokes for the first few minutes that it's running.

I know the compression is very good on this engine. I have never had any trouble starting it, hot or cold. I'm hoping this means my problem is not very severe. Should I try alumaseal first? I also read the intake manifold can be the problem. I need to pull the dynamic chamber and clean/oil the throttle anyway since I am having idling issues, so what can I look for to indicate that gasket is bad?

I'm just looking for some good first steps here. One of these days, I'd love to have this car running to the point where I can enjoy it. Thanks for the help

Does the smoke smell sweet like anti-freeze? Or bitter, like burning oil?

Are you certain you have no external coolant leaks? Check around the bottom of the rad, inside the undercover, and especially below the water pump. Also between the intake and exhaust manifolds.

The intake manifold has a pair of o-rings on channels that pass coolant through the intake. They have been known to go bad sometimes.

The smoke is not bitter. I've had cars burn oil before, and I really don't think that's what's going on here.

I also haven't seen puddles in my garage or anything, but I will double check. If it is bad o rings would that cause coolant to get into the engine and therefore cause all the smoke, or is that an external leak? Thanks for pointing out these common leak spots, I will take a look

Could be either; depends on where the o-ring failed. Internal would leak into the engine & be burned in the exhaust; external would likely drip onto the exhaust manifold, & could be getting burned off on the hot manifold.

Either way, you should smell hot antifreeze - has quite a distinctive odor.

Well my wife complains about the odor this car has when it is idling in the garage, even if just for a few seconds. So yeah... you could say it has a distinctive odor! I definitely think it's getting in to the engine somehow given the crazy amount of smoke on startup. The question is where. I will investigate this evening. Hopefully it isn't difficult to get the intake off?

Alright, I took the throttle body and intake manifold off tonight. The inside of the throttle body was filthy so I cleaned it and oiled it. I did not see any O-rings or honestly any physical way for coolant to get into the intake at any point. Can someone point me to a picture or diagram? I must have missed it. My intake manifold seems to be in fine shape and there is no evidence of coolant in the intake anywhere, although the dynamic chamber had an oily residue.

I did notice that there is a slight leak around my thermostat gasket (I recently replaced the thermostat) but that should not cause smoke. I did not see leaks anywhere else, but I am having trouble getting access to all the pipes near the water pump.

Here's a picture of the white smoke about 2 minutes after starting the car and letting it idle, just for reference (in case this is actually normal!)
http://austinbarnes.net/IMG_1092.JPG

The gsl se rotor housings don't use o rings between the lower intake and engine block like a 12a does.
I would be willing to bet your problem is the large o ring inside the motor that's between the rotor housing and irons, the only way to replace them is to tear the motor apart and rebuild it.
That's where I'm at with mine right now I have a 84 se that's doing the same thing.

Apologies- missed the part about this being an -SE.

Well that's fantastic. I bought this car less than a month ago and have barely been able to drive it 100 miles due to all the problems I've had. I bought it knowing it had good compression and thinking it was a good like new motor. Guess I overspent on it! And now I will figure out how to rebuild it

That smoke is totally normal when the engine is cold haha.

2 minutes of running is not going to take the SE off of its pig rich warmup cycle. I have a red 84 that does this every morning and has run this way FOR YEARS.

Mine has the RB dual exhaust so there are no cats on it anymore. Mine has done this since the factory exhaust was removed.


And my premix 12a in my 85 does it too. Engine is in fine health.

His isn't just smoking from cold weather though, it's losing coolant, and will continue to get worse.

Ooops....

Well, it could still be an external leak if that smoke could be normal. I don't remember it loosing coolant before I replaced the thermostat so maybe that gasket is the issue and the leaked coolant just burns off, or maybe I didn't get the system full and it is still sucking some coolant in. Or a combination of the two.

It's funny that you mention the exhaust. I have the same RB exhaust with no cat. I never thought that could impact the amount of smoke coming out? I'd say that I'll look for a factory exhaust... but it sounds so dang good!

I think my best course of action here is to replace the thermostat gasket, continue to look for external leaks, keep an eye on the coolant level, and if all else fails try some alumaseal before resorting to an engine tear-down. Thoughts?

Edit: I know my engine is also "out of tune" because it doesn't idle correctly and I have so far failed to get the TPS adjusted correctly using multimeters. I am trying to tackle one problem at a time so I haven't figured out the idle issue yet. Is it possible I am running overly rich right now?

I also premix, as a precaution. I still have the oil metering pump too. Is that ok? Overkill?

I already took it off but mostly to clean out the filthy throttle body to try and fix idling issues. It comes off in about 5 minutes, no big deal.

There are people here who have reported good results with alumaseal on small to moderate internal coolant seal problems. I've never used it, myself.

Your plan sounds reasonable, to me; it can sometimes take a while to get all the air 'burped' from the cooling system after repairs. Considering the time and expense required, a rebuild is generally a last resort even though rotary rebuilds are not nearly the chore that a piston-engine overhaul can be.

Just keep a tight eye on coolant level and operating temperatures, and never allow the engine to run low on coolant & overheat as that will damage more expensive parts.

AlumaSeal does work for metal to metal seal issues like around the housings and so forth. Its
worth trying and it doesn't take much. I think I used about 1.3 the bottle to help mine.