Engine Running Too Cold 160F

[jeepsrock]

The temp outside is about 65F and i have been driving the jeep on the street for 15 min and the temp hasnt gone more than 160F, unless i sit at a signal /stop sign for a min or so it goes to 210 but as soon as i go it goes back to 160F.

The first idea that came to my mind was that the Tstat is stuck open but i decided to pop open the hood with the engine running to feel the rad hoses. The bottom one was hot but the top one was warm but squishing it gave me the impression it had nothing going thru it ??? If the thermo was stuck open wouldnt the top hose have water thru it ??

Also this thermostat was repalced less than 6 months ago when i replaced the radiator with a modine, the tstat is a mopar 195.

THanks
pete

[langer1]

Sounds more like low on water.

[scca28]

The first idea that came to my mind was that the Tstat is stuck open but i decided to pop open the hood with the engine running to feel the rad hoses. The bottom one was hot but the top one was warm but squishing it gave me the impression it had nothing going thru it ??? If the thermo was stuck open wouldnt the top hose have water thru it ??

How is the coolant level? This sounds like a neighbors van, coolant was so low she wasn't getting a proper reading from the temp sensor. I guess it was just reading the air in the coolant chamber instead of the coolant that should have been there. Also, it might help if you can burp out all the air from the system. One more thing, check to see if the heater valve is working properly. If it is stuck open, your heater core will act like another radiator and slow down the warming up of the engine.

[bewilderedbeast]

Maybe you should check the gauge and sender to see if they're working properly.

[selarep]

just do a complete flush on it, its only like 15$ at most to do so, and while you're at it check the Tstat.

[jeepsrock]

Well before i dive in and do something un-necessary, this morning i ran the jeep again and it pretty much avergaed at 160F again.

I checked the coolant level and its where it needs to be. As for the sensor and guage while the jeep was running i disconnected it and it went all the way to the cold and if i let it idle for a while it does get to temp (210) so i do think the sender and gauge are working.

As for the Tstat if it is stuck open will i know when i take it out ? What will it look like if its stuck, its the stock mopar one ? Are there any Tstats that dont get stuck open ?

pete

[bewilderedbeast]

If the stat is stuck open, you will get up to temp, just slower.
If you can find a Robert Shaw stat, those are very good. Also sold as Mr. Gasket, I think.
Stant Superstats are okay too.

[Rocketman]

Murray's, Advance Auto, Napa ALL sell the Robert Shaw themostat but under other brand names. Ask for a 330-195 for a stock 195* or a 330-180 for a 180* for you obsessive types!

[jeepsrock]

Well i just opened the thermo housing to takea look at the thermostat. Its looks like its supposed to, it isnt stuck in the open position ?

Or can it be stuck open and exhibit the same looks ?

pete

[Rocketman]

You have it open, might as well replace it. Less to do another day.

[jeepsrock]

Well i did try something, i think it may meen something.

I had an older jeep thermostat laying in my box, i decided to put both that one and the one i took out in some bioling water with a thermometer attached. Both of them exibited the same behavior until 190F the one that was in the jeep at 190-200 opened all the way while the older one i got from my box of junk opened a small bit more and as the temp went up but still relatively small amount.

I think this may mean the thermostat out of my jeep is openeing too early and too much. I am on my way to get another, funny thing is its a dealer one.

Pete

[hotrodXJ]

I think this may mean the thermostat out of my jeep is openeing too early and too much. I am on my way to get another, funny thing is its a dealer one.


Still have a receipt? Sounds like a parts warranty to me.

[churky89]

Well before i dive in and do something un-necessary, this morning i ran the jeep again and it pretty much avergaed at 160F again.

I checked the coolant level and its where it needs to be. As for the sensor and guage while the jeep was running i disconnected it and it went all the way to the cold and if i let it idle for a while it does get to temp (210) so i do think the sender and gauge are working.

As for the Tstat if it is stuck open will i know when i take it out ? What will it look like if its stuck, its the stock mopar one ? Are there any Tstats that dont get stuck open ?

pete

I don't think there are ANY t stats that DON'T get stuck open.
Actually if it didn't open at all that COULD cause a boilover.There is a T Stat called FAIL SAFE....It IS designed to stick open,therefore eliminating the possibility of a boilover.
Remember the more coolant you keep in the engine,the better your chances are of possibly blowing a hose...

[jeepsrock]

Well guys here is an update...

After doing my boiling test and seeing how early and how much the thermo opened i went out to purchase another thermostat. I didnt want another dealer one so i called autozone and kragen and what i ended up with is a superstat by stant. It feels pretty heavy compared to the OEM unit.
Anyway i put it in last night and it seems like its back to normal. The top hose gets really hot tho i cant feel fluid thru it, maybe its just me. The jeep gets warmed up in a few min like its used to and the heater gets boiling again.

And yes hotrod i did call the dealer and he said i needed a reciept to return it , whihc i cant find.

Thanks guys.

pete

[90Pioneer]

I have this problem on cold days, runs at about 150-160. But then on hot days it runs 10 or 20 degrees too hot.

I have the modine 2 row radiator and factory 195 t stat which is 8 months old.

[jeepsrock]

I would highly recommend you look at your tstat and test it with a working one in a pot of boiling water. I think mine was bad for a few weeks now and in the hot days its not very apparent or atleast it wasnt for me, until the days have been getting cooler.

The fact that its a factory tstat also makes me wonder, since mine was a factory one too.

pete

[philip_g]

My car sort of does the same thing, it'll heat up to just above 210 on the gauge then it's like the stat opens and it'll cool back down to about halfway between 210 and the mark left, repeat.

always figured it was sort of normal.

[jeepnuts311]

i dunno why you guys are complainin about runnin cold. after owning 2 XJs for 8 years or so, one has always had the 195 and ran just fine, and the other one i use a 160* thermostat and it runs better IMO.

the 195* is in a 1995 H.O. and the 160* is in my 90 renix beater. the 90 on 33" tires and 3.55 gears gets 20mpg and so does the H.O.

on a very hot day on the trail i will get to 220* i also have a tranny cooler and it stays about 160 as well (measured on the cool side of the cooler)

a lot of people say dont run 160* thermostats but they cant convince me.

-Tim

[87manche]

i dunno why you guys are complainin about runnin cold. after owning 2 XJs for 8 years or so, one has always had the 195 and ran just fine, and the other one i use a 160* thermostat and it runs better IMO.

the 195* is in a 1995 H.O. and the 160* is in my 90 renix beater. the 90 on 33" tires and 3.55 gears gets 20mpg and so does the H.O.

on a very hot day on the trail i will get to 220* i also have a tranny cooler and it stays about 160 as well (measured on the cool side of the cooler)

a lot of people say dont run 160* thermostats but they cant convince me.

-Tim
Running a lower temp thermostat does not make your system cool better. The purpose of a t-stat is no to cool the engine it's to keep it warm.
If you have to run a 160* t-stat to keep from overhating then you've got other cooling system issues.

[jeepsrock]

The reason i was complaingin was becasue the jeep was running rich and my mileage was horrible. I was getting 8-9mpg and this is my daily driver so i cant aford to have it run like that. Maybe if it was my 2nd car i wouldnt care all that much , anyways in a few days of driving we will see if my mileage goes back up.

pete

[Oizarod115]

Running a lower temp thermostat does not make your system cool better. The purpose of a t-stat is no to cool the engine it's to keep it warm.
If you have to run a 160* t-stat to keep from overhating then you've got other cooling system issues.

my cooling system works great, i just like it to run a little cooler than normal. whatever temp t-stat i get thats the temp it runs.

-Tim (jeepnuts311)
(this is my brothers name, im on his comp)

[jeepsrock]

Thx guys for all the help on this one, apparently that was the prob....I drove the jeep a few mornings (cold wheather) after the thermo change and it warms up within a few min of driving.

pete

[Blaine B.]

I thought they always keep a receipt copy, and give you one....

Well, congrats. I just added a Stant Superstat thermostat and am happy.

A guy on JeepsUnlimited was saying "even superstats don't work correctly in a Chrysler" engine......so I asked him what he meant, and I'll let ya know if I get a response and explination.

[jeepsrock]

thanks..let me know
pete

[87manche]

I have a superstat in mine, after I went through 3 regular ones I decided to splurge and see if the $10 one worked better than the $4.
It does.
I think that t-stat's are just really hit or miss as to the quality. I pulled the fualty ones out, put them in a pot of water, none of them opened anywhere near what they should have, and they weren't consistent either.
I should say that I had one regular stant that worked well, but an extended period with the temp guage in the red killed that one.

[churky89]

Could be a possibility that the radiator cap is not holding the pressure....:cheers:

[Blaine B.]

I took my 2 month old AutoZone thermostat out and replaced it with the superstat. Before i threw it away I put the AutoZone thermostat in a pan of boiling water over the stove....

Well it never opened. And water boils after the temp it is supposed to open, right?

[Ecomike]

I took my 2 month old AutoZone thermostat out and replaced it with the superstat. Before i threw it away I put the AutoZone thermostat in a pan of boiling water over the stove....

Well it never opened. And water boils after the temp it is supposed to open, right?

Check out this link. You can calculate the boiling boint with the online tool there. Boiling point varies with altitude, or ambient atmospheric pressure, high and low pressure weather systems.

I plugged in 10,000 ft. altitude and got 193.6 F :cool: as the boiling point.

Mike McGinness
South Houston, TX

[Blaine B.]

Can't be driving a 90 Wagoneer up there then, can ya lol.

[Ecomike]

Can't be driving a 90 Wagoneer up there then, can ya lol.

No, Not with out a pressurized system, LOL!:D

:compwork: But wait, :idea:if I disconnect my coolant temperature sensor, & O2 sensor, & remove the thermostat, and let it run real rich (and of course if I owned the local oil well, :laugh3:) I could run a leaky, open coolant system way up there at 10,000 ft. :woohoo:, cause it would never reach 190 F.

Mike McGinness
South Houston, TX