Overheated on highway ==> Thermostat?

[benyandthejets]

Hey guys I recently had to pull over on the highway because I an engine light came on and my temp gauge was shot ALL the way up. I want to clarify that I chose to pull over the car was seemingly running okay and I didn't notice anything amiss besides the light and temp gauge.

The light was the top on the left side, which I believe is the transmission symbol. The temp gauge needle was over the top of the gauge. I haven't turned on the car since, I had it towed back to my house (thanks AAA). A few nice people stopped by and one mentioned it was probably the thermostat.

I did some research on this board and some people have mentioned having trouble is their air vents not heating properly and the car overheating saying it is probably thermostat which leads me to believe this guys hunch was correct because I have also had air heating issues in the past few weeks/month.

Thoughts? I don't have a whole ton of wrenching experience but I have most the tools I think I would need and I am up for the challenge as long as I don't have the pull the transmission or something. I'm checking out the manuals on this site and figuring out what parts I will need.

Thanks everyone in advanced!

tldr
- Replace thermostat because of overheating & air heat issues?

[benyandthejets]

Okay looking at the manual on this site it doesn't look too horrible. It looks a little cramped but I suppose I can disconnect the sparkplug wires and some of these random other harnesses. Any tips?

How do these replacement parts look?

Thermostat (w/ thermostat seal = gasket right?)
http://www.napaonline.com/Catalog/Catal ... 0293225913

And then the O ring that the manual says to replace
http://www.napaonline.com/Catalog/Catal ... 0067080797


For quick reference I'm going off this page:
http://www.mx-3.com/manuals/showimg.php ... E2-008.gif


One final thing.. so the coolant tank on the right side of engine bay had never had much liquid in it, even when engine has been sitting cold for a few days. Its been like this since I bought the car over a year ago and its been in the shop a few times for engine work. There have never been any problems including driving the car during last summer. It sounds bad but it hasn't been a problem and the mazda dealer mechanics apparently checked all fluids various times so I'm not sure if this is a problem...

[kulluminati777]

uh are you sure its the thermostat and not the water pump or bad rad caps.....

[benyandthejets]

uh are you sure its the thermostat and not the water pump or bad rad caps.....

Not sure at all.. any tips on checking the water pump or rad cap?

[SuperK]

make sure you didn't lose a belt on the water pump.
Then check your coolant level and see if it's low.
Make sure there is also coolant mix in the reservoir.
Start the car and observe the water pump turning and continue filling the radiator. Check to see if it's circulating coolant. Once you top the coolant off (while the car is running) and you can observe the coolant level from the radiator cap hole, you should be able to give it some gas by the throttle body actuator. It should "pull" in coolant. This should determine that your water pump is working still.
If it does NOT pull in coolant, the thermostat COULD be stuck closed. The thermostat will be the easiest and cheapest item to change.

Change the thermostat then repeat the test.

If it still does not pull in coolant, then put the radiator cap on, and see if there are bubbles coming out of the reservoir. Lots of air bubbles could mean bad head gasket, which will cause overheating.


You probably will need to run the engine at normal operating temperature, paying close attention that you don't overheat again.
Make sure your radiator fan turns on as it should when it reaches operating temperature.


Also post up where you are, maybe a local member will be willing to help you troubleshoot in person.

Since you are in Oregon. There are several very intelligent forum members in your area (and one very unintelligent one )

[kulluminati777]

and one very unintelligent one

[benyandthejets]

make sure you didn't lose a belt on the water pump.
Then check your coolant level and see if it's low.
Make sure there is also coolant mix in the reservoir.
Start the car and observe the water pump turning and continue filling the radiator. Check to see if it's circulating coolant. Once you top the coolant off (while the car is running) and you can observe the coolant level from the radiator cap hole, you should be able to give it some gas by the throttle body actuator. It should "pull" in coolant. This should determine that your water pump is working still.
If it does NOT pull in coolant, the thermostat COULD be stuck closed. The thermostat will be the easiest and cheapest item to change.

Change the thermostat then repeat the test.

If it still does not pull in coolant, then put the radiator cap on, and see if there are bubbles coming out of the reservoir. Lots of air bubbles could mean bad head gasket, which will cause overheating.


You probably will need to run the engine at normal operating temperature, paying close attention that you don't overheat again.
Make sure your radiator fan turns on as it should when it reaches operating temperature.


Also post up where you are, maybe a local member will be willing to help you troubleshoot in person.

Since you are in Oregon. There are several very intelligent forum members in your area (and one very unintelligent one )

Thank you a ton for the detailed trouble shooting! I am going to give this a couple reads and work through it.

I'm located in Corvallis, go beavs If anyone has any free time to help in the next few weeks I'd be more than happy to buy you lots of beer or whatever.

I'm about to take a look in the manual, but do you guys have an preferred coolant mix? I'll have to go buy some.

[SuperK]

premixed coolant, the 50/50 mix, is a ripoff. Buy full strength concentrate and mix your own with distilled water preferably. 50/50 mix is good to -34 degrees F so if that's fine for your temperate area, then go for it.

Just remember to perform all tests at operating temperature. The thermostat should stay mostly closed when cold so you'll get some false readings that way.

[benyandthejets]

premixed coolant, the 50/50 mix, is a ripoff. Buy full strength concentrate and mix your own with distilled water preferably. 50/50 mix is good to -34 degrees F so if that's fine for your temperate area, then go for it.

Just remember to perform all tests at operating temperature. The thermostat should stay mostly closed when cold so you'll get some false readings that way.

Gotcha, 50/50 will be fine for where im at. And okay. I guess I'll need someone to keep an eye on the temp gauge so I don't get too high.

[benyandthejets]

This is the timing belt/water pump belt correct? Looks intact to me but it was hard to tell from manual exactly where everything is.
(Yes, that is a lego keychain light haha..)




Filler Cap: Unless I'm reading the manual wrong, there should be coolant visible here? It ambiguous about which cap its talking about on E2-4




Reservoir:

Essentially empty except a little on the bottom.. nowhere near the low mark.

album of all photos together:
http://imgur.com/a/6mguE

[SuperK]

It seems you were critically low on coolant. You should fill it and keep an eye for leaks. The radiator and or hoses and or cap may leak. There is also a small line that goes to your oil filter that can also leak.

[benyandthejets]

It seems you were critically low on coolant. You should fill it and keep an eye for leaks. The radiator and or hoses and or cap may leak. There is also a small line that goes to your oil filter that can also leak.

Do you say that because of the reservoir or because of the fill cap level? I'm only curious because the reservoir has been like that for probably over a year(I realize a reservoir low is a terrible idea, I'm not hopeless. But I assumed the mechanics looked at it and the car had been running fine). I'll keep an eye on everything and i'll fill the coolant back up haha..

[mitmaks]

Replace cap and refill coolant in reservoir and the radiator/where cap is at. Drive it for a bit and check for leaks.

[benyandthejets]

Replace cap and refill coolant in reservoir and the radiator/where cap is at. Drive it for a bit and check for leaks.

Thanks for weighing in! I will definitely keep an eye for leaks. I'm looking at the manual and it is very ambiguous when referring to the filler cap and the radiator cap.

http://www.mx-3.com/manuals/showimg.php ... E2-006.gif

On this page it details how to refill the coolant. Do I pour the coolant in the filler cap or the radiator cap (in addition to the reservoir)? I only ask because it says pour the coolant into the radiator through the filler port. Basically Filler Port vs Label #2 on this diagram:
http://www.mx-3.com/manuals/showimg.php ... E2-002.gif

[SuperK]

fill it up by the filler cap next to #8 on the second link.
The filler cap is the cap on the passenger side, the radiator cap is on the drivers side.

Here are some directions from wytbishop that has a pretty clear explanation of some steps:

With the engine running, but COLD, remove the top filler cap on the passenger's side of the engine and fill right to the top. Now leave it off and carefully remove the rad cap. This will allow any air in the radiator to escape. Replace the rad cap when it gets to the top and then fill the engine right to the top again. Make sure the overflow res is filled to the bottom line and your cooling system will be totally full