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Unread 12-08-2012, 02:07 PM   #1
Bren Gun
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Thermostat In Backwards?

Could I have? I changed out a failed water pump last weekend and while I had everything drained, decided to change out the hoses, the belt, new coolant (to replace the stuff puked out on the driveway...) and the thermostat, Stant 14369. As I got to start putting it all back together I realized that the new thermo didn't have a long piston like the OE and it had a plain gasket wrapped around it. The OE had a tab on the gasket that located it in the thermo housing and this one didn't so I located the new thermo and the air bleeder hole in it like the old one, but I agonized over whether to put it off and double check at the parts store. But I cross referenced it online with the Rock Auto part in the link above and decided to use it.
Everything back together and no leaks, burped and air bled the system, etc... My wife takes it out a couple of days later for a longer day long drive and yep, it started leaking, a few drops from the top radiator hose. Well, I think probably a poorly located clamp and so I fussed with it a bit and added a second hose clamp to make sure. Warmed her up and no leak, BUT... it suddenly occurred to me, COULD I have put the new thermo in backwards in a blonde moment (without the tab on the OE gasket one could reverse it...)? Would that have caused the leak at the top hose because it built enough pressure to just leak from the weakest point? Thing is, its not overheating or running warm. The needle stops at the midway point of the gauge where it always pointed fully warmed up. But the bottom radiator hose NEVER warms up. Would that be normal as the radiator is supposed to be returning cool coolant to the engine? Or am I sitting in a time bomb waiting for a pressure leak somewhere else?
If the thermo were in backwards wouldn't it cause the engine to overheat? But shouldn't the bottom hose be at least warm? Help save me from myself and save me the PITA from draining the radiator tomorrow and pulling the hose and housing to check...

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Unread 12-08-2012, 08:06 PM   #2
streetglideok
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If I recall, the thermostat's backside, the plunger side, should be inserted into the engine side, and the pointed end towards the hose end. I prefer to avoid the aftermarket t-stats, because of the differences you witnessed yourself. Some do not put the air bleeder on their thermostats, even when the vehicle calls for them. This causes overheating on some vehicles. Others, are spec'd wrong, and cause overheating(2.2L OHV GM 4cylinders, spec is 180* in the lower hose, some aftermarket brands including stant made them 195*). Often times, when you disturb the spring clamps, you can get a hose leak. Make sure all the air is purged from the system and its at proper temp. I use http://www.newegg.com/Product/Produc...-pla-_-NA-_-NA when filling most of the newer cooling systems, it saves alot of trouble filling subarus, VW/Audis, etc that we see.
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Unread 12-09-2012, 06:41 AM   #3
Bren Gun
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So, anyone else? In short, does the fact that even though the bottom radiator hose is ice cold, I am getting normal heat and normal engine temp mean nothing is wrong? Am I over thinking this? I just want a second opinion from someone who has a bit more experience with Libs than I.
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Unread 12-09-2012, 08:02 AM   #4
streetglideok
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Your lower hose is the return hose from the radiator to the engine. Its always going to be cooler than the upper hose, or it better be! Depending on ambient temperature, and if the heat is going, etc, that hose will not feel warm at times. It going to get warm when the t-stat has to open up to control the engine temp, but with this being winter, the things barely open up.
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Unread 12-09-2012, 10:00 AM   #5
Bren Gun
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Quote:
Originally Posted by streetglideok View Post
Your lower hose is the return hose from the radiator to the engine. Its always going to be cooler than the upper hose, or it better be! Depending on ambient temperature, and if the heat is going, etc, that hose will not feel warm at times. It going to get warm when the t-stat has to open up to control the engine temp, but with this being winter, the things barely open up.
Thank you, that's what I thought, but I really needed a second opinion to ease my mind.
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Unread 01-14-2014, 07:01 PM   #6
spud962
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Does anyone know if the after market thermostat can be installed backward?
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Unread 01-14-2014, 08:41 PM   #7
TwoBobsKJ
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Quote:
Originally Posted by spud962 View Post
Does anyone know if the after market thermostat can be installed backward?
Yep, it's very easy to have it turned around the wrong way. It should be installed as streetglideok described above.

You'll know after a fairly short drive if it's in backwards. The temp gauge in the dash will climb over the midpoint as you go faster and will drop back down as you go slower - the exact opposite of what it should be doing. With a backwards thermostat as the engine warms up the stat moves "open" but it's actually closing down, stopping coolant from flowing. As the engine cools the stat "closes" but since it's backwards it is actually opening relative to the way it's installed, thereby letting more coolant flow through the system.

Bob
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Unread 01-14-2014, 09:02 PM   #8
RockRollin
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It will take heat to open and cold to close regardless which way its installed. The problem if backwards is the wax capsule will not be exposed to the heated coolant. However a thermostat will become somewhat passive with the increase of pressure as the engines coolant expands. So you will still have a temp that rises and falls dramatically. If your temp is stable/normal, then the thermostat is in correctly. A side note, most all thermostat housings are designed with a low clearance to prevent installing backwards.
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Unread 01-15-2014, 12:29 AM   #9
profdlp
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I'm not an expert, but I seem to recall reading a thread recently which stated that there is a special gasket for the thermostat which comes separately and must be used or it will leak. I remember the thread because people were (reasonably) complaining that it ought to be included with the thermostat itself, since the old one is not reusable.

Or maybe I'm full of beans. (Again...)
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Unread 03-26-2014, 04:49 PM   #10
Bren Gun
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Well 15 months later... Got home to notice a small bunch of drops of coolant on the ground under the jeep. Its coming from where the hose joins the thermo housing, but I cannot figure out why its leaking? Nothing seems loose. I double checked the housing bolts, the hose clamp is tight, but how is coolant getting forced from the hose and clamp? Could there be a crack in the housing? The hose was replaced when I did the water pump, so its not that old.
Two clues- Over the past year and a half I've seemingly lost tiny bits of coolant so that I've been topping off the overflow tank constantly maybe once a month. I couldn't figure that out why I was always filling it. I just figured for a long time that it took this long to work all of the air from the system and that it was slowly bleeding itself. I never saw any coolant on the ground before now.
Second, granted its been a cold winter, but even last summer, it seemed to take forever to warm up. Today the needle got very close to where it should be, but not quite as warm as it normally is. It has never overheated or gone above what should be normal.
When I replaced the thermostat it was difficult to figure out which end was up as well as whether I possibly had it in backwards. There is a rubber o-ring that was supposed to be indexed to the thermostat with a rubber tab that wasn't a part of the o-ring that I got so I wonder if that could have something to do with it? Is there supposed to be some sort of small air bleed hole in the body of it? More of my confusion stemmed from the fact that I don't think mine had one... Any ideas before I have to drain this whole mess this weekend?
PS. I've been reading alot of bad reviews on this particular Stant thermostat as not fitting correctly... ToughOne-Thermostats Thermostat, 195 Degrees Fahrenheit 14369: Find car thermostats from the experts at Advance Auto Parts.
Thinking I may order one from RockAuto, a Motorad Fail Safe and replace it along with the housing, but I'd like to get an idea of what would cause it to leak....
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Unread 03-28-2014, 08:47 AM   #11
JeepCoMJ
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You don't have a tstat for a liberty, simple as that....meaning what you put in is for something else
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Unread 03-28-2014, 03:02 PM   #12
Bren Gun
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Quote:
Originally Posted by JeepCoMJ View Post
You don't have a tstat for a liberty, simple as that....meaning what you put in is for something else
???
Well, I know that the particular thermostat Stant 14369 I used is listed for several Chrysler models, but it is listed as the correct one for my '03 Liberty.
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Unread 03-29-2014, 11:19 AM   #13
JeepCoMJ
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It is incorrect if the gasket doesn't locate it. I have done many, never had one with a gasket (actually a rubber seal) that didn't locate it, and never had one you could install any direction but one.
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Unread 03-30-2014, 08:00 AM   #14
Bren Gun
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Yeah, the gasket was a big confusion for me at the time. I'm still pretty sure that I installed it correctly. (After all it ran fine for over a year...) But I don't think that it is possible to install it backwards either in hindsight. I wasn't sure at the time after I had put everything back together.
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Unread 03-30-2014, 10:29 AM   #15
02blue
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Okay, been watching this for a bit and just happen to have mine disassembled at the moment. A factory Mopar Tstat cannot be installed backwards in my 02. The plastic housing cannot accommodate the shoulders on the spring side. The Stant (14369) can be installed backward. I don't think the index tab makes much of a difference in the Stant Tstat as long as the can be bleed valve is properly oriented in the housing.

I've decided to go with a factory replacement and will save the Stant for an emergency. I don't like the gasket that came with the Stant. Pretty sure it will leak eventually and my factory one was likely original w 160k and never leaked.
img_2610.jpg

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