Temp gauge not working
 

After driving for two hours at seventy miles per hour, don't you think the temp gauge should at least read in the middle? Because mine hovers just over the C.

How do I fix this, and all that. Is it a common problem?

are you sure the car is running warm, try turning your heater on, does it blow hot? It could be perhaps your thermostat is malfunctioning and is stuck open, or that you don't have one at all.

Hm... No, it wasn't hot. Well, actually, it may have been. I"ll check later. But what am I in for if my thermostat doesn't function?

Pulling the thermostat out and replacing it silly.. :)

It's not too bad, just drain the coolant, undo the upper radiator hose (better idea than trying to leave it on.. 'sides, you probably need new hoses anyway, never hurts to change them if they have any kind of milage on them), and remove the 2 or 3 bolts holding the upper pipe to the thermostat housing.. pluck out the old thermo, install the new one, and installation is the reverse of disassembly.

I'd suspect a bad sender though, I find it hard to believe that any car can run just above C for any period of time, even with an open thermo and the fan constantly running..

PaulC

If it is stuck open you will have hardly any heat, your car will take forever to warm up, and possibly slightly reduced gas mileage.

Its easy enough to change, two 12mm bolts, a little gasket sealer, and a bit of coolant. :)

Re: Temp gauge not working
 

I don't understand...
You were blasting it up to 70mph or were just kist highway cruising at 70mph?&nbsp What was ambient?&nbsp Everything sounds fine to me - the car is SUPPOSED to run this cool...



-Ted

I think "just above the C mark" is a bit too cold. It should run about 1/4 of the way between C and H (on a S4 anyway).
I had this problem on a car once (not a 7); the temp gauge struggled to get above C even after a decent drive. Replacing the thermostat resulted in the temp gauge sitting at half way (where it was supposed to be), getting there in under 5 minutes, the heater actually working, a 10% reduction in fuel consumption and a generally "nicer" running car! Best $15 I ever spent. :D

The reason I made that comment is...

My cars runs like that.&nbsp Mind you, I've got a "cored" thermostat, and 1/4th up reads just about 190&#176F on my SPI water temp gauge.&nbsp Half way, IMO, is too high - this reads 220&#176F on my SPI water temp gauge.

What I think is that most people cooling systems are full of gunk and corrosion.&nbsp I used to have those 1/2-way average stock temp gauge readings until I did my modified flush procedure which got rid of a LOT of crap in the cooling system.&nbsp Ever seen the flush, the stock water temp gauge reads a LOT cooler thab before...

http://fc3s-pro.com/TECH/MODS/COOL/cooling.htm
My modified cooling system flush procedure...



-Ted

Its funny that I just mentioned the exact same procedure to someone asking about flushing the radiator...;)

What's to the coolant flushing, anyway? I'll pick up a new thermostat this week (how do you tell they're broken?)

The ''best'' way involves removing it, but hell, for all that trouble, might as well spend $10 and get a new one.

Yeah, I guess so. But the coolant flushing?

No it bloody isn't! I wish people would stop saying that, it's BS!

Read this thread of flushing your cooling system.
Note running this cool would also explain the defrosting problem in your other thread.

Did you not see the fucking quote marks? I don't do it!

Settle down. Sorry if I misunderstood, but your quote marks didn't change the meaning of your statement. If you don't do it, why make the comment?

Thanks, guys. So... I should *replace* the thermostat, not remove it or core it out, right? And this may wind up also fixing the defrosting problem, yes? (Thanks for checking my background.)

Definitely replace it, use a Mazda one only.No promises, but your heater will work better so it probably will help. :)