uRizen

iTrader: (2)

It was below zero today, and driving to work was just fine. I put a remote start unit in my FC and usually get it nice and warmed up before heading out. After 10 minutes she's nice and toasty and ready to go.

Well, this afternoon was a little different. The car only had ~3-5 minutes to warm up and I had to head out to get to court to take care of a speeding ticket. I got in, started cruising down the highway, and noticed my water temp. was starting to get a bit higher then I like it.

I haven't driven it in the cold alot, and only two times when it hasn't been warmed up before-hand. Those two times, the water temp. would go to the halfway point, and then the heater went down in temp, and the water temp. guage started to drop back down to the below 1/4 point it normally rests at. I assumed this was the thermostat in action, since my Accord did something similiar.

Anyways, it hit the 3/4 mark today, and started to smell like syrup, so I pulled into a Menards parking lot, let it sit for a minute (temps stayed the same), and shut 'er down. When I opened the hood there was plenty of fluid all over my nice clean engine bay (yay), and steam everywhere.

I went into Menards almost crying, but excited at the same time because I might get to rebuild a rotary (wierd, eh?). I grabbed some 50/50 coolant premix, and some gloves to hopefully fix 'er up. The system was pretty pressurized and you could here boiling near the bac valve, so I turned the caps on the resivoir and the neck just enough to let the pressure out, then filled 'er up.

I couldn't find any leaks on the hoses, and never have had coolant on my garage floor, so I was pretty confident all my seals and hoses were ok. I started the car up, and it dropped to the normal operating temperature pretty quickly, and I could find no smoke comming from the housings, and no syrup-smelling exhaust, so I'm confident my seals are a-ok.

I'm guessing it was caused by a stuck thermostat, which hasn't given me any problems before. I do have to clean the mess up tonite when I'm putting my new y-pipe in to check for leaks more thouroughly. What do you guys think happened?

nopistons

So the coolant/steam came out of the filler cap when the pressure shot up? Sounds like the t'stat stuck, as you said. Easy enough to change it to find out. Everyone seems to recommend using a genuine Mazda t'stat, not an aftermarket brand. (If you put your old one into a pot of boiling water, you should see it open, just to check it.)

Syonyk

Given the erratic temperature behavior you've seen, I'm guessing your thermostat is probably sticking (as you've guessed as well).

If the engine overheats and boils, coolant will spray out of the overflow bottle overflow (overflow overflow?) and get all over the place. Also, a weak radiator cap could let coolant spray about, or let hot coolant get into the overflow bottle when it shouldn't be.

My suggestion would be to replace the thermostat, replace both your radiator caps, fill it up, and see how it does. If a radiator cap is weak, you can "overheat" and spray coolant all over at relatively low temperatures (230, 240F). Since you didn't run the engine for long periods of time after you noticed it, things may very well be just fine.

Rebuilds are fun, but a running '7 is more fun. Don't jump on the phone to order a rebuild kit just yet.

-=Russ=-

uRizen

iTrader: (2)

Hehe, thanks guys. I'm actually quite releved that it's probably just the t-stat. They're pretty cheap too, so I won't anger the wife again.

It seems to be fine now though. I've been out and about for the last 3 hours running erands, and it hasn't gone crazy again. Maybe it was just from not warming up propery. I'll keep my extra coolant and gloves in the bin and see what happens from here. I'd rather not do any cooling service until the summer, because I want to do a very thourough flush (open up the housing plug at the same time and flush all the way through), and I need to replace the temp. sensor on the lower corner of the radiator too.

I've never done my own radiator flush, but have heard it's extremely easy to do. You can flush it with a regular garden hose followed by some distilled water and filled with that pre-mixed 50/50 anti-freeze, right?

Aaron Cake

iTrader: (1)

Stop doing this. It's bad for the car, bad for the environment, and bad for your pocket book (gas prices). Also a safety hazard.

You need to find the leak. If you had coolant everywhere, then there is a leak in the system. I often have success finding leaks by squeezing the upper rad hose, which pressurizes the system. The leak then becomes obvious.

If you start the engine, you should also see steam coming from the leak as it warms up.

Your high temperatures may be a result of the leak, or a bad thermostat.

But no, it is not a result of not warming up the car "properly", since you aren't doing that anyway.

Start the car, then do up your seatbelt, check your mirror, and then start driving. Drive easily until the car comes up to normal temperature. That is a proper cold start.

nopistons

If you wait to fix this, you can bet that it will happen again. And remember that unlike a piston engine, overheating a rotary engine can often destroy it. (That's upwards of a couple of thousand dollars, all told, for a rebuild, vs. a few bucks to fix the problem now.)
"An ounce of prevention is worth a pound of cure."

uRizen

iTrader: (2)

I know rotaries hate overheating, ths I was freaking the hell out on the way home. I check my oil pressure and water temp more then I check my speedo while driving, hehe.

I pulled the thermostat and it responded correctly when I tested it via the FSM procedure, and cleaned it out a bit (wasn't too dirty, but had a couple of small deposits on it.

It was still leaking a bit of fluid, and Aaron's method did show any leaks, but I finally pinned it down. It's the stupid pressure cap leading the overflow tank. I had all the splooged coolant cleaned out, and as soon as you give it throttle, you could see steam coming from under it. So, that's not a huge deal in any way, those little buggers are cheap, so I should have it taken care of.

As far as my warmup procedure, I don't like driving it without a bit of a warmup. The tranny is very sluggish, and sometimes gets a bit crunchy because my synchros suck. Pollution isn't a big deal either, my cats are all gutted ATM until I find replacement. I'm thinking on grabbing the Catco high-flow replacements that Summit sells.

nopistons

You mean the cap that's on the neck above the t'stat? Mine leaked a few years ago and the coolant got into the wiring harness connector right at the base of the neck, leading down to the ACV, shorted them out, burned the wires clean free of insulation, and burned the connector off of one of the solenoids on the ACV. Check yours to see if the same happened.

uRizen

iTrader: (2)

I just replaced the wiring on the ACV a couple of weeks ago and wrapped everythign in loom. I cleaned all the coolant off of everything I could get to and all teh wires and connectors are ok. I was the lower cap that's leaking though, the one on the neck is ok, but I'm replacing it anyways.

missourimatthew

Hey thanks for this thread. i had a friend that had water boiling in the overflow and the motor would get hot and then cool down from 3/4 down to 1/2. i showed him the post and he changed the thermostat and it worked!!!!!

ilike2eatricers

holy crap 4 year old thread resurrection!!!!

cpubugs

Thats a good sign means people are searching! Hooray for ressurections!!!