particleeffect

Up untill a few days ago, maybe a week (before I ran the car hard at the track if anyone is wondering), I'd never had overheating problems. I did have a bad water seal somewhere causing bubles in the water and steam during running and water flooding after shutdown, so I did the CRC blockweld treatment -which worked like a charm. I ran 2 bottles of CRC and the rest distilled water for somewhere over a month -up untill tonight when I flushed the system because I suspected that the CRC was getting the system too dirty to cool properly (even at highway speeds).

I have a linearized temp guage BTW.

So, tonight I drained the system, dumped around 2 gallons of normal water through, and filled it with distilled water (~only a gallon, yes I drained from the block too). Figured that there was just alot of water left in the system, and some, as I could see, blockweld mixture. Filled it off, idled, filled, blah blah. Took the car around the block to see if the temp stayed normal (~70 degree evening) and it just kept climbing so I came towards home, pulled the hood release and idled back with it still climbing -pulled in with the guage at H. The engine was clearly overheated, so I let the fans run for a while with the hood open.

The entire trip, I got NO hot air out of the vents with the heat on. It just blew cool evening air and of course, didn't help the motor temp.

It doesn't seem like my water pump went because I seem to have pressure under idle with the motor cool, or did atleast before I left.

...

spurvo

thermostat stuck closed? Is the radiator getting hot?

particleeffect

Oh yeh, radiator doesn't seem to be getting hot.

spurvo

Ta da! The thermostat is getting stuck closed and not allowing coolant to flow through the radiator.

DO NOT DRIVE THE CAR!!!!!

Get a thermostat FROM MAZDA. It is designed to open at the correct time (temp, 177F start open, medium by 180, fully open by 203F) and has a very nice little hole with a pin in it that really helps with re-filling the system. The T-stat comes with the rubber gasket that goes around the T-stat body, and place it into the water pump housing with the hole/jiggle pin topmost.

Don't just pull the T-stat and run it open. You actually hurt this motor by doing so. The T-stat isn't terribly difficult to do, and in your case MUST BE DONE.

particleeffect

Damn looks like I gotta pull some things like the Y-pipe and maybe the air pump to get to it, oh well, sounds right. rgr on the no driving.

thank you, will get or order one tomorrow.

-edit, is this the part some people swap with a miata peice to run slightly cooler? something I should do?

spurvo

Miata piece is a thermoswitch. It is physically a little pointy sensor type thing screwed into the backside of the thermostat housing, more or less right behind where you're looking from the front. There was a thread about the miata thermoswitch just the other day, so look back three or four pages.

The T-stat replace is just like they have it in the manual. The air pump is a bit of a hassle. I find that pulling the belt, then the short bolt on the bottom, then the long bolt through on the top, then moving the air pump body up and down while prying with a screwdriver works. Note that the output rubber hose won't come off while keeping the air pump in place, so don't try. Just loosen/remove the clamps, rotate the hose to make sure it is free, wiggle the pump while prying, and be prepared to catch it once it comes free.

While you are down there, check the condition of the little hoses that run from the water pump housing into the turbo area. These hoses can go bad, and in a really unpleasant way. Look for swelling around the clamp, a really flexible loose feeling hose, and any greenish dust liek residue. If you see any of this, order new hoses for the turbos and swap them more or less as soon as you can.

Good hunting with the T-stat.