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Discussion Starter #1 (Edited)
Just thought I would document my thermostat replacement. I was pretty sure mine had been stuck open as it took forever to get to operating temperature (and made the heater pretty useless in the winter). I had seen the Autozone part number (15378) listed elsewhere and decided to make a go at that, knowing that I could always order the entire unit from Centerline if I messed it up.

Removing the old T-stat

Just a note, this is much easier with the hood removed. Like many others here, one of my T-stat bolts sheared off when I tried to remove the housing. If viewing the engine from the front, it was the rearward drivers-side bolt. It wasn't the threads that were siezed, it was the unthreaded shaft part of the bolt that passes through the T-stat housing. By disconnecting all of the hoses and wires, I was able to rotate the upper housing around (counterclockwise) the sheared bolt. This gave me enough room (as it had unscrewed at least one thread or so) to get a prybar between the upper and lower T-stat housing, and I was able to pry the upper housing free from the sheared bolt (there are no threads in the upper housing, just the lower). The stock bolts are 70mm long or so, I was able to make due with the largest that Home Depot had in stock (60-65mm) for a cheap replacement. I also replaced the twin small water hoses that go to the engine block with some Autozone bulk hose trimmed to fit.

Modifying the housing

The stock housing has two "ears" that need to be removed to fit the new thermostat. Here is the stock housing:



First I ground off the two ears with my Dremel (I don't have fancy air tools and such):



Then I sanded down and cleaned up the surface around the whole housing so it was smooth (Dremel again, with sandpaper cylinders and some hand sanding):



Here is the new thermostat sitting in place:



Now, for the important part so y'all don't have to run to Autozone and buy a second T-stat like I did. You need to drill a small hole in the perimeter so the water can flow through to the bleed screw (orange arrow above). However, you can't just drill it anywhere as the "wings" on the new thermostat (blue arrow above) will only fit into the housing in a few different orientations, because of the trio of water temperature sensors. Hence, test fit everything together so it fits, then send a small drill bit or other marking tool down the bleed screw opening so you know where to drill/grind a small cutout for the bleed screw (I think grind is easier since its hard to drill a hole that close to the edge).

Here is my finished install (don't use this a guide for notch orientation, as I think this is from my first attempt where I ground the notch in an arbitrary place).



Reassembling the housing

Once everything is lined up (I stuck a piece of wire through the bleed screw cutout to keep it from rotating) you can reattach everything. Since I'm impatient and didn't want to wait for a new gasket, I just used the thermostat gasket maker goop. Big gotcha here: The thermostat sits slightly proud of the housing, as you can see in the above pictures. Without a gasket, the upper housing bolt holes can crack (they are thin small castings) if you tighten it too much, so tighten it just enough to seal. Then just refill with coolant, drive and enjoy!

Mine's been working for a couple months now, temp gets to 180 or so in a hurry and sits there steady, even in stop and go traffic. I'll let you know how it handles the peak of NC summer in a couple months!
 

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Looks good! Much cheaper than the new ones, plus readily available replacement parts.
 

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Nice description! I would like to try it myself, but would like to find similar thermostat in Sweden. Could anybody help me with what car it is actually made for?
 

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Vehicle application?

Id also like to know the vehicle specific application, as we dont have AutoZone here in Canada...I suppose I could call them to find out as well.

it would also be cool if the same t-stat was available in a 190°F version for when it gets really cold. Running it warmer during these times helps keep the oil cleaner and makes those short trips less harsh on the engine.

...but we never drive them when its this cold out anyways ;)
 

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I just tried the Autozone site, and checked compatibility with an 84 Ford Ranger, 2WD, 2.8L, 6 cyl, with 2bl. Says it is compatible
 

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Gates cross reference for Murray 15378

33056 = 160 degree
33208 = 180 degree
33209 = 195 degree

33208S = Premium 180 degree
33209S= Premium 195 Degree

Stant cross reference

13376 = 160 degree
13378 = 180 degree
13379 = 195 degree



45378 = 180 degree
45379 = 195 degree
 

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ThankYou for good info! Seems the T-stat is commonly used in a lot of cars in Europe. Easy access and cheap to buy in europe also!
 

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there is a VERY close to stock no need to mod teh housing t-stat that autozone sells ..youll only need to trim a tiny little tab off the t-stat and its still only a 8$ unit...ill see if i can dig up the part#
 

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look up a t-stat at autozone for an 87 milano and it will pop right up..i remember having to do a little bend pver much like the original bar type as well as a light shave to make it fot correctly but it proves there crazy close to stock and availible

 

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Discussion Starter #12
Yep, that's the part number (15378) for the t-stat we're using above, you can see it matches the pictures I posted.

Not sure how you got it to fit without removing the tabs from the housing, but I'd be happy to learn!
 

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i trimmed the edges of it with a dremel till it slid in like the stock unit would have and then dimpled the edges on each side of the tabs to make sure it couldnt walk out...worked like a charm

ill have to do another one soon enuf
 

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Am I correct in thinking that it's advantageous to have the opening temp "LOWER" (ie 160 vs 180) in hotter climes like Tx and Fl?

Gary
 

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Am I correct in thinking that it's advantageous to have the opening temp "LOWER" (ie 160 vs 180) in hotter climes like Tx and Fl?
No.

If you are having overheating problems diagnose & fix it. A lower T-stat will prevent the engine from reaching proper operating temps. The computer will read that as 'not yet warmed up' and keep the fuel mixture in its default warm up mode (slightly richer than ideal).
 

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to add to this...

its also proven, that running higher coolant temperatures increases combustion efficiency, and reduces the amount of wear on the piston rings and cylinder bore.

modern engines run very hot in comparison to older 80's engines, and its what helps get them better fuel economy. today expect to see average 200°F coolant in econo-box engines.

this of course goes only to a point, as oil also has an ideal operating temperature, and if exceeded will cause sludge and other nasty things.
 

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Thanks. My car doesn't run hot I've just always thought it should run cooler. Must be all those years of driving British cars which did run too hot.
 
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