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Coolant thermostat replacement


James Morse

1997 XLT 4.0L 4x4 1999 Mazda B3000 2wd
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Can't find good video or anything on this. Searched posts.

Do I need to drain system first? If this isn't high spot coolant will run out.

I've done them before on other vehicles, looks like take off radiator hose if you want then two bolts, take out old, put new, I assume with new gasket that should come with it(?). They told me here use 190-195F thermostat.

I'm wondering am I missing anything, and, would this be a good time to flush the system because the coolant looks kind of yucky. If I want to flush it then probably I should do it first but I guess it doesn't matter. I assume there is a drain on the bottom of the radiator?

Sure would appreciate any help.
 


ericbphoto

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If you're going to flush the system anyhow, go ahead and drain it. If not, you won't lose too much coolant from the t-stat hole. It's easy. Make sure you have a new gasket. Don't assume there's one in the box with the t-stat. For draining, there should be a drain cock on the bottom of the radiator. But taking the bottom hose loose is faster.
 

James Morse

1997 XLT 4.0L 4x4 1999 Mazda B3000 2wd
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Thanks Eric, that sounds great. Much appreciated.
 

Burnsy

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Did you change it out yet ?
 

James Morse

1997 XLT 4.0L 4x4 1999 Mazda B3000 2wd
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4.0L in XLT, 3.0L in B3000
Transmission
Automatic
2WD / 4WD
4WD
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31x10.5-15 K02's on the Ranger, 235/75R15 on Mazda
My credo
The perfect is the enemy of the good.
@ Burnsey: Yes.

https://www.therangerstation.com/forums/index.php?threads/what-is-temp-of-heater-air.195383/

That thread has a lot more info about it and about flushing engine, radiator, and heater core.
Get the gasket when you get the thermostat, it doesn't come with the gasket and you want to clean off any old parts of gasket or whatever might have been put on there like silicone etc.
Hose clamp pliers help immensely in moving the hose clamps to get hoses off for flushing.
Lot more details in the linked thread, how to do everything. You'll want to take off intake tube, very easy to do. I think everything is covered in there.
 

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