41 replies to this topic

[Justin Fowler]

I figure one of the two is having a problem, but both are fairly new. The thermostat I replaced looked brand new but I decided to put a new one in anyways, and the waterpump looked brand new with no grease,dirt or oil on it when I did my rebuild, might be biting me in the butt now.

I should have just went ahead and replaced the pump but decided not to, what does this sound like to you?

So pretty much I just ran the car for about 10/15mins. I wanted to run the engine to operating temp to see if I could get any air out of the cooling system but when I popped the cap I got showered with cool water! The water was still cool, not even mildly warm. When I did the initial break in of my new motor I noticed it was spitting out water, but soon stopped and seemed like it flowed great through the radiator, like the thermostat was sticking. Does anyone recommend removing/drilling or modifying the thermostat first? or does this sound like my pump?

[pitbull113]

gut the old stat and reinstall if it doesn't come up to normal temp it's the pump. my moneys on the stat.

edit: just reread what i wrote if the pump is bad it'll run too hot not cold. duh

[Justin Fowler]

Gut as in just keep the outer ring? or should i try drilling holes? I will gut it now and see what happens

[Keith Novak]

Take the t-stat, and put it in a pot of water on the stove with a thermometer on the water. Heat the water. See what temp it opens. I've bought new stats that don't open before.

[Justin Fowler]

I just did that, and it opened. The one I guted completely flowed water, but eventually water started bubbling up and over flowing, then went back to flowing, and so on and so on over and over.

[pitbull113]

do you mean with the cap off bubbling out of the rad? cuz it'll do that as the system builds pressure..

[Justin Fowler]

Yes that is what I mean, I was not sure if it did that considering the cap is right above the fins, as other radiators are on the side they dont tend to bubble like that, not familiar with these mazdas so I am not sure if I have a problem or not.

[pitbull113]

it sounds like the stat you had in was good since it did open in boiling water. if the gutted stat is still in the engine close the cap run the car and let idle until temp comes up if it doesn't overheat no problem. then reinstall new stat. done. just keep close eye on temp gauge as they can go from cold to too hot quickly if there's an issue. with a gtted stat it could take 10-15 mins to reach normal temp at idle. if your fan is controled by a toggle keep it off until temp reaches 170 or so then turn on. if it hits 210 shut it down

[Justin Fowler]

What is the best way top off the radiator? Just jack the front of the car up or run the car and top off?

[pitbull113]

fill it with the engine off. the level will drop several times until actually full. start car let idle with cap off as temp comes up level may drop continue to fill when it starts to rise or flow out install cap. then do as i described before as far as temp watching.. check level when cool in overflow bottle.

[Justin Fowler]

Thanks SAE, I will give this a try tomorrow.

[pitbull113]

you're on your own now justin. bed time for me good luck and update the thread so i know how you made out. hate to say it but me thinks you didn't have a problem . just didn't give the car enough time to warm up but better safe than sorry right?

[Justin Fowler]

Just glad I had a spare thermostat. I let the car warm up earlier today for about 10mins and the cap/hoses were all cold, didnt feel like much pressure but shot every where when i cracked the cap. These miatas are a lot different then the cars I am use to working on, just trying to figure everything out before I get my build done. Appreciate the help, will update tomorrow! Night all

[Tom Hampton]

Justin I run without a tstat as recommended by davew.

[Justin Fowler]

Running no thermostat can cause the engine water to boil up couldnt it? and the high flowing current wont cool like it is suppose to. That is my experience from radiators, are these miatas different?

[Tom Hampton]

No. That's not how thermodynamics works. More flow always equals better cooling.

[Justin Fowler]

I will have to look into this

[Keith Novak]

Sometimes running with no thermostat actually makes the car run too cool so that it doesn't get up to a temp where it gets into the happy range for power. Then you wind up either blocking off part of the radiator to get the car hotter, or putting a t-stat back in to reduce flow until it gets to temp.

[Tom Hampton]

True...but, rare in Texas. It was 89 last weekend.

[pitbull113]

Running no thermostat can cause the engine water to boil up couldnt it? and the high flowing current wont cool like it is suppose to. That is my experience from radiators, are these miatas different?

you are correct justin. with some cars the water will pass through the radiator to fast and doesn't get cooled if there's no stat. Run the proper stat for the temp range you want your engine to run at.one more thing please do not open the radiator cap on hot cars again.If that water that splashed on you was 200 degrees you would be a hurtin' right now. don't ask how i know.