2003 Protege5 - Engine runs hot fast and no check engine light

HeSmash · September 8th, 2011, 07:59 AM

Hi All,

I've got a 2003 Protege5 (auto) that's been running really hot (possibly near overheating) within 10min of driving under very light conditions.

There is no warning light or check engine light coming on. Coolant level is fine and the fan turns on no problem.

If I turn the heater on high and run the fan at level 2 or more the engine temp stays normal.

I have a feeling that it maybe the thermostat valve (which I've read is an easy fix).

Does this sound right? I'd like to try the fix myself if it is the thermo valve, but I kind of want to get a diagnosis from a mech.

Any and all help is greatly appreciated!

Thanks!

Brian MP5T · September 8th, 2011, 08:27 AM

Coolant level in the bottle does NOT mean that the coolant level in the Engine/Radiator is good..

This 100% sounds like a T-Stat.

Very simple job.

1 Gasket
2x 10mm Bolts
Coolant.

HeSmash · September 8th, 2011, 08:35 AM

Thanks for the quick response.

Am basically looking at doing this "http://www.mazda3club.com/showthread.php?t=44997" right?

I've also got the Mazada service manual for safe measure.

thuzil · September 8th, 2011, 08:38 AM

The part from mazda has the rubber gasket already on it.

September 8th, 2011, 07:59 AM	#1
HeSmash Members Join Date: Sep 2011 Posts: 2	2003 Protege5 - Engine runs hot fast and no check engine light Hi All, I've got a 2003 Protege5 (auto) that's been running really hot (possibly near overheating) within 10min of driving under very light conditions. There is no warning light or check engine light coming on. Coolant level is fine and the fan turns on no problem. If I turn the heater on high and run the fan at level 2 or more the engine temp stays normal. I have a feeling that it maybe the thermostat valve (which I've read is an easy fix). Does this sound right? I'd like to try the fix myself if it is the thermo valve, but I kind of want to get a diagnosis from a mech. Any and all help is greatly appreciated! Thanks!

September 8th, 2011, 08:27 AM	#2
Brian MP5T 2010 Donating Member Join Date: Sep 2003 Location: Ottawa Ontario Posts: 3,828	Coolant level in the bottle does NOT mean that the coolant level in the Engine/Radiator is good.. This 100% sounds like a T-Stat. Very simple job. 1 Gasket 2x 10mm Bolts Coolant. __________________ Brian \| WAY NORTHSIDE \| 2002 White Protege5 www.mp5t.com

September 8th, 2011, 08:38 AM	#4
thuzil Vendors Join Date: Oct 2009 Location: Steel Town Posts: 1,015	The part from mazda has the rubber gasket already on it. __________________ I'm catching the 4:00 train north to Ecuador

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September 8th, 2011, 08:35 AM	#3
HeSmash Members Join Date: Sep 2011 Posts: 2	Thanks for the quick response. Am basically looking at doing this "http://www.mazda3club.com/showthread.php?t=44997" right? I've also got the Mazada service manual for safe measure.