Coolant seal leak that healed itself
 

So about a year ago I was posting a fair bit about my problem with a slow but steady leak of coolant into my 2007 RX-8's motor when I'd let it sit for a period of 24+ hours. On startup, I'd get lots of white smoke, rough idling, and a misfire code for about 30-45 seconds until the coolant was expelled from the motor. The longer I let the car sit, the worse this would be. I can't think of anything other than a coolant leak that would describe these symptoms. I also think I may have overheated (slightly) the motor in the months preceding the first obvious event.

Anyway, at some point over the summer this problem seemingly corrected itself. Now, I can leave the car sitting for 2 weeks (did just recently, but don't often) and it will start up very smoothly with no white smoke.

Over the summer in very hot weather I again slightly overheated the motor once (needle just started to move and I pulled over to let it cool completely). Could this second overheating incident have possibly 'warped' the seals flatter again? Don't know if that's even possible. Or perhaps carbon buildup has sealed whatever had been leaking? Or some other form of detritus?

Motor seems pretty strong at the moment at all rev ranges and I'm happy with how it's running (other than tendency to overheat on hot days in bumper to bumper traffic, which I just avoid entirely now).

Any thoughts? Should I think of getting a rebuild at this point before I do any real damage to the engine? I'm at 75k miles on the first motor.

I don't run premix (I know, i really should, and am going to start) but take good care of the motor otherwise. I also don't drive it very hard, although do rev it out at least once per day.

Thanks!

the fact that your car is overheating on hot days is a problem in and of itself. You should be able to idle in traffic no problem... that's what your fans are for.

As far as a water seal magically repairing itself I doubt it'll stay that way for too long.

I understand that overheating is a problem. I ordered a tactrix/mazdaedit to change the fan triggers. Also flushed coolant. If these don't resolve the problem, I will look into other solutions (new fans, new radiator, etc).

As far as the water seal 'repair' not lasting a long time, it's already lasted about 8 months and 10k miles.

My question is: what do you think caused the issue to resolve itself (whether permanent or temporary)?

Anyone have ideas?

Dannobre?

Maybe a piece of coolant seal dislodging itself and then something else (debris) re lodging in its place later on giving the water jacket a temporary "sealed" effect?... Unlikely but plausible.

No idea about how it sealed. You're really lucky man! But getting the MazdaEdit to lower the fan trigger temp won't fix your issue. If you're overheating in traffic/idle, your fans are already spinning on full speed. Getting the fans to turn on earlier will only delay the overheat. Never fix it. What does this all mean? Your fans are failing. Overheating only at idle leads to a fan problem. The fans turn off when you're moving at speed. They might be spinning fast, and they might be loud, but they're not spinning FAST ENOUGH. S1 fans are known to slow down over time. When electric fans fail, they don't stop spinning completely. They just slow down. Does it overheat while moving? Even a little bit?

I'm assuming you live in a hot climate. I have the same problem in my car. Idling in the hot sun would get the temp over 220F. I never let it overheat because I monitor them from an OBD2 gauge.

If I were you, I'd get new fan motors. See if that fixes the problem, then go from there.

As a safety measure, next time it overheats, turn on the heater on full and watch your coolant temps drop :) The heater core acts as a secondary radiator for the coolant. Should save you from a rebuild :) you also can tell when the car is about to overheat. The AC won't blow cold air when the coolant temp goes over 230F.

Good luck and keep us posted :)

Thank you for your detailed response! Everything you mentioned is true, and I've suspected the fans for a long while. As for turning on the heat, it has been the first thing i've done at signs of overheating (as you mentioned, as soon as the A/C stops blowing cold), and it has always very quickly brought the temps down. I'm talking within 5 seconds. Which is how I ruled out my thermostat being stuck closed.

I'll look into replacing the fan motors today! Also going to start running premix. Have been doing a ton of reading on here, and realize i need to go a step further in all of my maintenance/preventative care measures.

About time! :yesnod:

Well damn. With RX8Soldier's affirmation that my problem is likely fan related, I just popped off my airbox/battery/battery box to gain access to both fans. In the process, i noticed that a grommet was missing from the airbox...seemed familiar. And with everything removed, the passenger side radiator fan was completely stuck due to the grommet.

I removed the grommet and it spins freely now. Any chance this fan motor is salvageable? Or would it have been damaged due to the blockage? I have a multimeter.

To answer my own question, no the fan motor is not salvageable. Hooked it up to direct 12v and nothing. Did the same with the driver side motor and it fired up.

So now to replace the fan motor.

I did a search and could not figure out if this can be done without pulling the radiator? I have good access to the motors now (from the top) but the shroud is still connected to the radiator. Curious if I can pull the shroud enough to access the three bolts that h old the motor in place.

Damn. That sucks bro. Those grommets are pure evil. Too many cars die from them. Take out both. The air box can live without them. Don't risk it man.

No wonder you were overheating. It was running on 1 fan all this time! Your problem got a lot simpler though! Congrats for diagnosing it. Now comes the hard part. You can't take out the fan motors itself. You can't take out just the fan shroud/assembly either. You have to drop the entire radiator from the bottom. So you'll have to jack the front of the car up, or ideally, put it up on a lift.

When removing the radiator, there's a small hose that leads from the coolant reservoir to the top radiator tank. Be VERY CAREFUL when removing that hose from the radiator side, as the nipple that the hose fits to is made from thin plastic and it's VERY BRITTLE. Plenty of people have had to buy new radiators after breaking that nipple. What 9krpm suggested is you splice that hose from a razor and then replace it with a new hose. DO NOT manhandle it. IT WILL BREAK. If it doesn't come off easily, go grab a razor and slice and dice lol. Yes, you will have to buy a $20 hose. Better than buying a $200 radiator :P If you do break it, report back. There's a cheap solution we've come up with ;)

As for the burnt fan motor, has the connector that plugs into the motor itself sort of melted? I knew of a perfect car, had zero problems, and the owner loved it. He'd check the air filter etc all the time. Somehow while checking the filter, one of the grommets got dislodged and fell in, jammed the fan and overheated the car. His fan motor connector had melted because the fan got jammed. Luckily, he didn't blow a coolant seal, but while pulling the radiator out, the damn radiator nipple broke off! That guy used our solution to fix it. I'll start up a separate thread and link you to it, just in case.

Good luck :)

Also, spin the working fan by hand too and see if it spins freely. If you feel resistance or it stops too soon, replace it. Don't drop the remaining grommet while doing this lol. Take both of them off!

Thanks for the reply!

The motor does spin freely by hand but two 'clicks' are felt at 180* and 360* of rotation. When i hook it up directly to a 12v source, it spins very slowly and clicks a lot. Sometimes it doesn't spin at all, and i need to manually rotate the blade to a new position to get it to start up.

I'm thinking of buying a 12" Spal motor and 'grafting' it into the stock fan housing (while keeping the driver-side motor in place). These fans run approximately $110, which, in my estimation, is a fair bit cheaper than any other solution (other than buying a salvaged motor on ebay, which could be on its way out).

Thoughts? I'm also tempted to ditch the housing and run a single high-output 16" fan like one of the mods here has done. They aren't very expensive either, and can pull >2500 CFM.

Clicks when spinning? What fan are the talking about? The fan that got jammed on the other fan?

No idea about having a single fan bro. Wouldn't that require making a custom shroud? How much does that 16 inch fan cost? Whatever you do, make sure they're of good quality. Some cheap fans just stop spinning. You don't want that to happen while stuck in traffic. If I were you, I'd get the FAL 420s. They're a direct fit and comes with it's own fan controller to set the turn on temps. It's a big upgrade from stock. Should keep the car cool as a cucumber.

Talking about the dead motor clicking. Good motor spins nice and fast, and pulling amps in spec with service manual per my multimeter.

I realize the FAL 420 is an ideal solution, point is that I don't want to spend that much if I don't have to. Which is why i'd like to graft in a 12" SPAL or FAL fan (around $120) and call it a day. Unless folks here think there is an issue with that plan.

Got no idea about retrofitting those fans man. Might wanna wait until someone else chimes in. If they spin fast enough, you should be fine though.

Meantime I advice not to drive your car. But you probably know that haha.