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Closed Loop temperature?
- Thread starter fabjunkie
- Start date
- Location
- Antioch, CA
The actual temp will vary depending on your coolant temp sensor reading, but normal closed loop temp is anything above 170 degress for 91 and up XJ's.
- Location
- Antioch, CA
Don't believe me?
I've been a tech at Jeep/Chrysler dealerships for many years. Everything I have been taught is 170 is the closed loop threshold. Newer cars will be in closed loop after only a few seconds of run time regardless of temp.
Don't believe me?
I've been a tech at Jeep/Chrysler dealerships for many years. Everything I have been taught is 170 is the closed loop threshold. Newer cars will be in closed loop after only a few seconds of run time regardless of temp.
heh heh ...
Its not that I don't believe you ....
Its just that it seems that for every 100 people that get asked - there seems to 100 different answers .... :dunno:
Even here on
. So many even seem to think the thermostat sends magic messages to the computer and so on.
... And you offered up your employment history as the verification of your information ... Thank You
Well aware that "newer" vehicles are in close loop early ... An OBDII scanner solves that easy ... 97 XJ change over at approx 68'f coolant temp and within minutes of startup ... climate regardless according to feedback so far.
More interested in why earlier models would need coolant temps of up to 170'f to reach closed loop ???
Is it the non heated O2 sensors ... or is there something else. ???
:cheers:
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- Location
- WA state
a 180deg stat is usually only a band-aid for cooling/other issues.
- Location
- Antioch, CA
Not true, I have run a 180* thermostat for quite a few years in my 96. 195 is too hot for my liking.
- Location
- Antioch, CA
heh heh ...
Its not that I don't believe you ....
Its just that it seems that for every 100 people that get asked - there seems to 100 different answers .... :dunno:
Even here on
So many even seem to think the thermostat sends magic messages to the computer and so on.
... And you offered up your employment history as the verification of your information ... Thank You
Well aware that "newer" vehicles are in close loop early ... An OBDII scanner solves that easy ... 97 XJ change over at approx 68'f coolant temp and within minutes of startup ... climate regardless according to feedback so far.
More interested in why earlier models would need coolant temps of up to 170'f to reach closed loop ???
Is it the non heated O2 sensors ... or is there something else. ???
:cheers:
It is all about the adaptive strategy in the computer programming. OBDII XJ models may enter into closed loop earlier than the older models. However, you will set a rationality fault code for engine cold too long if you have anything lower than a 180* t-stat. So, the computer wants to see at least 170* maintained, and it needs to get there within a set amount of time as well.
I understand. Thanks very much for the info Bryan! Very cool..eace:
And Johnnie, I know that is usually the case. But out here in the desert, it will be 110+ throughout the summer, and on the hottest days be 115-118. So I prefer the t stat open early so I can have a cushion and keep an eye on things between 190-210. So when you start the truck after work and the coolant is still already at 120, I prefer to let the t stat open early and let the water get moving .
If the t sat doesn't open up till 195, that leaves me no room, plus the fan is going on-off all the darn time. We ran a 180 t stat on our 5.0 race truck and never had any cooling problems, and we ran the crap out of that thing never going faster than 45-50 most of the time.
No offense, just my .02, it's always worked well for me.
eace:And Johnnie, I know that is usually the case. But out here in the desert, it will be 110+ throughout the summer, and on the hottest days be 115-118. So I prefer the t stat open early so I can have a cushion and keep an eye on things between 190-210. So when you start the truck after work and the coolant is still already at 120, I prefer to let the t stat open early and let the water get moving .
If the t sat doesn't open up till 195, that leaves me no room, plus the fan is going on-off all the darn time. We ran a 180 t stat on our 5.0 race truck and never had any cooling problems, and we ran the crap out of that thing never going faster than 45-50 most of the time.
No offense, just my .02, it's always worked well for me.
You might not like it, but your engine won't have a problem with it. We try to keep the engine in our racer at 195-205. It was designed/tuned to run at that temp. Why mess with it?
I understand. Thanks very much for the info Bryan! Very cool..
And Johnnie, I know that is usually the case. But out here in the desert, it will be 110+ throughout the summer, and on the hottest days be 115-118. So I prefer the t stat open early so I can have a cushion and keep an eye on things between 190-210. So when you start the truck after work and the coolant is still already at 120, I prefer to let the t stat open early and let the water get moving .
If the t sat doesn't open up till 195, that leaves me no room, plus the fan is going on-off all the darn time. We ran a 180 t stat on our 5.0 race truck and never had any cooling problems, and we ran the crap out of that thing never going faster than 45-50 most of the time.
No offense, just my .02, it's always worked well for me.
You have PLENTY of room when your engine is at 210. With a proper mix of coolant/water and a good cap that holds pressure, your boiling point is up over 250. Let it run at 210 - it won't hurt it.
- Location
- Antioch, CA
Same thing could be said about stock suspensions, right? Just because you think it should be one way or the other doesn't mean that is the only way.
I had a heat soak misfire issue, well at least I did until I put the cooler thermostat in. To each his own. :dunno:
Making an engine run outside of its designed temp can't be compared to upgrading a suspension. Find the failing component that was causing the misfire instead of band-aiding it with the thermostat. If a component is failing when hot, then it is only a matter of time before it fails completely.
- Location
- Antioch, CA
You just like to argue, huh?
The problem wasn't the jeep, it is the crappy California gas with a high ethanol and or alcohol content. The fuel will atomize in the fuel rail during a hot soak, very muuch like the 2000 and 2001 XJ issue. How did chrysler fix that? They reprogrammed the electric fan to come on at a lower temp.
So, unless you have an alternative to the gas I buy at every pump here in California maybe you should quit while you are ahead.
Hellbent
NAXJA Forum User
- Location
- san diego, california
just to throw this out there....
at one time there was a chrysler part number for a 180 deg t-stat for the 4.0, was listed as being for use in very hot climate areas, i.e., the middle east, etc. when i checked dealerconnect, it was actually still available for order(a year or two ago). as per the factory, there could be a need for a lower temp stat.
at one time there was a chrysler part number for a 180 deg t-stat for the 4.0, was listed as being for use in very hot climate areas, i.e., the middle east, etc. when i checked dealerconnect, it was actually still available for order(a year or two ago). as per the factory, there could be a need for a lower temp stat.
Yes - you are correct ... Some people hope that fitting a lower thermostat will fix their failing fanclutch or radiator or water pump.
Thats when its a bandaid.
Other people fit a 180'f thermostat ( or similiar ) to enable full coolant flow at a slightly lower temperature.
Sometimes people who do this ... and live in very cold areas ... find that the engine running temp may actually get as low as 180'f ... in which case a different thermostat should be chosen. e.g. 182'/185'/188'/190'/192' etc ....
Sometimes the running temp may even be lower than the thermostat setting ... depending on the radiator style and fan setup and weather.
Its "designed" temp ... heh heh
Its got a 195'f thermostat ... that is the only controllable device that sets a minimum, "designed" engine temp ... strangely tho, it runs at temps well above the thermostat setting.
And then when it has a bit of load on it ... it runs even hotter ... above that "designed" temp everybody goes on about - Unless the factory cooling system is in perfect condition or you have snow up to your headlights.
Theres a few reasons for this .
1/.. Great big 4.0l i6 jammed in a 4cyl/V6 engine bay,
2/.. A "factory" thermostat that isnt fully open until 218'f, compared to other brands fully open at approx 205'f,
3/.. A barely adequate, std factory cooling system,
4/.. Emmission requirements,
5/.. People wanting "eco car" fuel economy from a 1980's vehicle,
6/.. Predominantly "cold climate" operating areas as the major sales market, e.g. a predisposition to interior cabin and demisting, heating requirements.
7/.. Differences in using anti-freeze mixes compared to water,
8/.. A known "hot" operating auto gearbox pumping hot oil temps through the radiator,
9/.. Poor vehicle service & maintenance.
This "designed" temp ????
If achieving running temps of 10'f - 20'f below are such a terrible thing to do ... How come running temps 10'f - 20'f above are OK ???? :dunno:
I would much rather have higher fuel consumption ( a debatable issue ) than blown head gaskets, warped heads and constantly failing, heat affected, electrical and rubber components.
Which is why I have used a variety of thermostats in the 180'f -195'f range for the past 12yrs, in 3 jeeps ... with no ill effects.
No ill effects ????? ..... Thats because of the climate the vehicles get used in ... (Equal to a hot texas summer for most of the year where I am)
Main point to consider is that there is a big difference between an engine running "efficiently" at high temps ... compared to its "effectiveness" at high temps.
Yep ....
Factory Option Thermostat ..... O.E. part number:..... 5202 8446 .. 180'f
The listing for it I found was just as a "heavy duty" thermostat not middle east specific ... and it was part of a number of XJ options to deal with "overheating"
Others included:
A 2 core radiator,
A brass / copper radiator ... listed for middle east market but would be very very useful in any "hot" climate.
A "heavy duty" bottom radiator hose ... probably had the internal spring,
The euro model, short lived, bonnet vent experiment,
And the second fan.
Variations of those options were fitted to U.S. market vehicles in an attempt to balance the cooling system .... No two XJs are the same people ... especially one in Toledo ... and one in Houston .... Which is something to consider when "debating" the merits of using various cooling sytem components ... and the engine heating device called a thermostat.
For our hot climates over here ... Chrysler did something really "tricky" ... They dangled the auto gearbox heat-exchanger in the hot side of the radiator instead of the cold side ... That was really well "designed". :doh:
Ohhh .. BTW ... The jeep suspension system was "designed" to be the "best" for the vehicles general operation ... same as the cooling system.
Bryan. C. thanks for your "loop" info ...
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Maybe you should be more open minded.
