Mazda 626 Thermostat?

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Hey everyone! My name is Jesseca(obviously) I have a 1993 Mazda 626 V6. In my Intro I mentioned that I just recently moved to Arizona, where it is like 100+ everyday. I was on the highway one day, noticed my car was getting hot as I was driving on the highway so turned the heat on but it already was passing the H(hot) so I pulled off at a exit to let it cool down, it didn't want to restart. When it finally did it would heat up really fast, it ended up being a belt that was somehow connected to the water pump ( I think). Thought I would be alright, well I don't have a problem say 10am or earlier, or say 6:30 pm or later, but in between those time slots, if I am driving (mostly on the highway),and I have the a/c on, my car gets to the H(hot) very rapidly. So I turn the heat on, let it cool down, and just drive without the a/c. It is definitely too hot in AZ to do this. I think it hasn't had a radiator flush in a long while so I plan on doing that (unfortunately I forgot all the paperwork on it in St. Louis and won't get it until Aug or Sept.), but do you think it could be the thermostat, and how easy is it to change it? (I am pretty good at figuring things usually (when I had my 1987 Celica I changed the Alternator Belt pretty easy and all on my own). I would just hate to take it back to the shop if I could do it myself. Thanks in advance!

posted by  jesseca

Yes it can definately be the thermostat. Could also need a cooling system flush and change. Can be both. That's why I recommend doing them both and see where that gets you.

posted by  DodgeRida67

Thanks for your response!! I will do the flush...is it easy to change the thermostat?

posted by  jesseca

changing the thermostat is not a 5 minute thing, but it can be done rather quickly and without much hassle. as for anything else, i would also check if the fans are appropiately working, specially the A/C fan. it might not be turning on and lets the car heat up.

posted by  Inygknok

Does the overheating happen all of the time or only in stop and go traffic?

electric cooling fan and /or associated fan relays, bad thermostat (most cars this is about 20-30 minute job), water pump (this is a pain in the butt to change on most Mazdas since it involves removing the timing belt), low coolant level or air bubbles in the system, cooling system needs to be flushed, outside of radiator full of bugs (wash radiator from back side with water hose and nozzle)

If you need further fan troubleshooting instructions, (if it does not come on when the AC is on or if it doesn't come on when the car is Warm or hot and is @ idle) let us know since I will need to look @ a wiring diagram before I can tell you exactly what to do

Check the simple stuff such as coolant level, etc first.

If the thermostat is even suspect, replace it since they are only about $10.00 - $15.00 including gasket

posted by  tbaxleyjr

Something that people do in very hot weather places is totally remove the thermostat.

This gives them about 20 extra minutes of the car being cool.

This is just a stop gap sort of thing but something to consider especially in the summer. If your car is sitting in 100 degree heat it doesnt need as much warming up, so a much lower degreed thermostat than stock or no thermostat at all would be necessary


In most cars, the thermostat housing is connected to the end of the upper radiator hose. you will have to drain a lot of coolant out.

It is not difficult only the access to it can sometimes be blocked by something else.

posted by  stamar

dbl post

posted by  stamar

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