Coolant Temperature in the winter

projectJ · **Joined:** Sat Jan 19, 2008 4:23 pm **Posts:** 8

Can anyone tell me what the thermostat temperature range is for the 2.8L? In the winter according to my scan guage I never get over 160. Summer it's about 170-175. I realize diesels run cooler but 160 seems too low which affects my fuel mileage. No DTC's and the fan isn't running.

Thanks
ProjectJ

CRDMiller · **Posted:** Sat Dec 05, 2009 2:50 am

According to GDE. YMMV

Joe Romas · **Posted:** Sat Dec 05, 2009 8:03 am

Mine runs, once warmed up, is at the 176 mark winter and summer :lol:

ATXKJ · **Posted:** Sat Dec 05, 2009 8:10 am

If it's cold outside - you need something to block the airflow -
the diesel doesn't produce enough heat - and if it's too cold the viscus heater will run

the FIA front - is popular
http://www.gofia.com./index.cfm?pageID=14&productSeries=2&acc=1&model=181&year=2005&step=3

(the thread pictures went away)

and someone mentioned Lund
http://www.autotrucktoys.com/liberty/Lund-Jeep-Liberty-Plastic-Cold-Front-Winter-Grille-Inserts-02-04-P7919C494.aspx

or you can make your own from Coroplast

kdlewis1975 · **Posted:** Sat Dec 05, 2009 4:14 pm

I have the Lund(s). They are for '02-'04 models and you'll have to trim about half an inch off to fit them in the '05/'06 grills. These just cover the grill slots, so the opening under the bumper will still let a fair amount of air through...but I figure it probably needs at least a little air. The install is pretty easy once they're trimmed...getting the grill unsnapped without breaking tabs is probably the hardest thing to do. I do wonder how important the CAC is during the winter months, because blocking off the grill is going to reduce the amount of cooling it can do.

mikey1273 · **Posted:** Sun Dec 06, 2009 2:01 am

Mine was running at the 176 mark untill it got colder the other day now its a tick below that.

tjkj2002 · **Posted:** Sun Dec 06, 2009 9:46 am

CRDMiller wrote:

According to GDE. YMMV

Not accurate.The OEM temp gauge is not a actual temp gauge,it's a relative temp gauge which give a temp range and not a actual temp.Right from the '05 FSM.............

Quote:

² Engine Temperature Normal Message - Each
time the cluster receives a message from the PCM
indicating the engine coolant temperature is within
the normal operating range [up to about 124° C (255°
F) for gasoline engines, or about 110° C (230° F) for
diesel engines], the gauge needle is moved to the
actual relative temperature position on the gauge
scale.
² Engine Temperature High Message - Each
time the cluster receives a message from the PCM
indicating the engine coolant temperature is high
[above about 127° C (260° F) for gasoline engines, or
112° C (233° F) for diesel engines], the gauge needle
is moved into the center of the red warning zone on
the gauge scale.
² Engine Temperature Critical Message -
Each time the cluster receives a message from the
PCM indicating the engine coolant temperature is
critical [above about 132° C (269° F) for gasoline
engines, or 115° C (239° F) for diesel engines], the
gauge needle is moved to the high end of the red
warning zone on the gauge scale.

ac5501 · **Posted:** Sun Dec 06, 2009 10:01 am

I'm noticing with the GDE tune, the running temp drops more then with stock. I'd say my Jeep is running between 10-20 degrees cooler then last year.

FIA has a custom fit for the CRD (it has a bug screen for the summer too). I have not installed it yet.
Got it from RealTruck part is FIA-WF927-6

I'm hoping it will bring the heat up a little. From what I've noticed these few weeks, the fuel economy really drops when you get under 40 degrees.

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

The temp gauge that someone posted is accurate...it is for the 2006MY CRD. The 05 and 06 had different gauge calibrations. We also posted the 2005 CRD calibration somewhere on this forum as well as the GDE forum.

For temps in between the tick marks on the gauge, the needle will typically not move much. The temps at each tick mark are accurate.

There is quite a bit of difference in the gauge calibration between the two model years.

MrMopar64 · **Posted:** Sun Dec 06, 2009 8:14 pm

tkjk2002,

the factory service manual that you've quoted is only correct for 2005 vehicles which have not had the cluster update. All 06 vehicles (or any 05 with the update) should have the new cluster calibration which does not match the service manual description but also prevents the gauge from rising too quickly and giving the operator false overheating information when in fact the engine is just fine.

The thermostatic valve on the KJ starts to open at 80C. If your engine is operating less than 80C then either you need to block the radiator opening some with a winter front, cardboard, blanket, etc. or the thermostat isn't closing completely.

ATXKJ · **Posted:** Sun Dec 06, 2009 8:40 pm

and for those of us enamored with traditional units 80C = 176F
which is one tick left of center

bewestro · **Posted:** Mon Dec 07, 2009 9:26 pm

Is it normal for it to lose temp if the engine is unloaded? I've noticed, while driving, the temp will get up to the 176 mark but if I stop and put it in P or N it drops to a tick above the 1/4 mark in a minute or so. I have an '06. This only happens when it's cold out.

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

This is perfectly normal for a diesel. At light load there is just not enough heat being produced to keep the coolant at operating temps. This is one reason the KJ has the viscous coupling heater, if coolant drops too low after the engine has been idling for some time, the viscous heater will turn on. This adds friction heat to the coolant and additional load on the engine.

nursecosmo · **Posted:** Tue Dec 08, 2009 10:53 am

I use the Fia blanket for my rig in the winter(in fact I'm putting them on both of my vehicles today). when the temp is below zero, I really can't notice any difference on the gauge when driving, but when I shut it off, it seems to hold heat longer. This is just an impression and not scientifically tested. Realistically, it does very little on either of my vehicles, but they do look cool.

Coolant Temperature in the winter

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