My temps hover around the first large mark on the temperature gauge, which other posts indicate is 150 to 156 degrees F. Posts suggest that the thermostat has failed in the open position.

Has anyone tried to restore the function of their thermostat, instead of replacing it? Remove scale or precipitate, get the mechanical portion moving again, or otherwise cleaned it?

If someone has successfully restored function, what did you do, and how did you replace the seal(s)?

Thanks.

I believe the theory is that the spring weakens over time allowing opening at too low a temperature. The 1/4 mark is somewhere in the high 130s, I think.

DOC

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2005 KJ CRD Ltd Detroit TrueTrac Bilsteins G2 GDE "HOT" ECU GDE TCM "Tow Tune" "euro" TC SEGR Weeks Elbow New HG at 130K ARPs Clean CAT aFe Filter Magnaflow Exhaust EHM Cumminos In-Tank Lift Pump Hayden Fan Clutch Nylon Fan VH Enabled with GDE lower shutoff point Recalibrated Temp Gauge Tekonsha Prodigy Sears P-1 ZDDP

From what I've seen replacing failed thermostats there was been no evidence of any material buildup that would inhibit proper performance such that cleaning would do any good. Not saying that such a situation is impossible. If you want to see detailed pictures of what the assembly looks like and why it's not possible to disassemble to clean or replace the funtional part go to viewtopic.php?f=5&t=50940

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Sold to LOST member my 05 Ltd, GDE Stg II turbo + TCM tune, SunCoast TC w. Transgo kit, Steiger window regulators, Samcos, Fumoto valve, 2nd gen filter head with Lub. Spec. bleeder, Hayden clutch & 11 blade fan, inverted spare, P-1 battery, BF Goodrich Long Trail TAs, Etecno1 glow plugs, timing belt at 50K miles/8 yrs

Thank you for the replies. I understood that thermostat portion could not be replaced. Many other non-Jeep Internet resources refer to techniques for cleaning thermo, which would still be applicable to the VM thermo/hosing.

50% higher than anticipated fuel cost and no cruise are making thus vacation drive less than pleasant. Dealerships are quoting $1000 to trouble shoot and fix issues. Still looking for options to throwing money at it with good chance of not getting issues fixed. I've had less than good luck with Jeep service departments in the recent past.

You could temporarily place an in line thermostat in the vehicle for the balance of the trip to increase the operating temperature. Members are using an in line unit from an 1.4L Renault Encore or similar and securing it in the radiator hose. I have a 192F unit in mine currently. Temperature runs near dead center on the gauge.

palouse - I see you have an mpg and other issues post in addition to this one so here goes:
1. 650 miles from point of purchase in Decature, AL and the ambient temps you are reporting indicate your location, you really need to add that to your signature in case someone is nearby, is well into "winter" fuel land. Winter fuel as I understand can knock an easy 10% off your mpg and I know from personal experience that a tstat that's causing the temp gauge to ride at 3/8ths or so can knock off 10%. So at guess you are down 20% from expected warmer weather mileage. X2 on a inline for a short term fix, I prefer the OEM for long term.
2. not sure what you mean by pinion factor but I assume it relates to speedometer and odometer readings. Those can, IIRC, be slightly adjusted by a dealer but only based on pre-programmed tire sizes. In the real world both those readings come from different sources and can be off in different directions by as much as +-5%. The only real way to check is with a GPS, try a couple of 25 mile relatively straight and flat runs for the odometer check, and then apply a correction factor.
3. tire pressure matters as does clean drive line and tranny fluids, also there is a rubber boot on the front calipars that can swell causing slight brake drag and killing mpg. The parking brake assembly is a drum brake inside the rear discs and that can also drag.
4. real world mpg on mine before GDE tune with good tstat and OEM tires was 18-19 in town (9 mile commute, relatively flat, stop/go, average speed 25mph) on highway 27-28 (interstate, relatively flat, 62 mph corrected, ca. 1,800 rpm). Post GDE tune 22 or so in town and 30-33 on hwy same driving conditions. I will note that post GDE tune pulling a horribly heavy horrible aerodynamics trailer from here the South Carolina and back I got 18.5mpg vs. pulling a 5X8 uhaul behind my son's CRD from Tempe, AZ to here we got 22mpg.
5. no cruise - I'd look at wheel speed sensors (know to have the wire break inside the insulation) and hubs.

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Sold to LOST member my 05 Ltd, GDE Stg II turbo + TCM tune, SunCoast TC w. Transgo kit, Steiger window regulators, Samcos, Fumoto valve, 2nd gen filter head with Lub. Spec. bleeder, Hayden clutch & 11 blade fan, inverted spare, P-1 battery, BF Goodrich Long Trail TAs, Etecno1 glow plugs, timing belt at 50K miles/8 yrs

Actually, there are two methods for setting odo and speedo. A good post with pics is on this site or similar showing screen shots of the tool that allows access to the system. Tire size does not determine "rotations per mile", according to the tire manufacturers. Tire design and construction is different between tires of same size, impacting rpm.

I am buying #2 now. Diff between #2, #1, and mixed covers maybe 5% of the 40% total loss. Temp is the only change between now and last August.

I am testing a $0.39 fix for the thermostat issue. Thermo pegged at"12:00". Hoping it will adjust mileage. Starting another trip tomorrow, it will take a few fill ups to tell.

FWIW, I was just quoted $425 to replace the thermostat at Buerge Jeep in Santa Monica. Mine seems to be stuck in open, too.

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2006 CRD w/99,300 miles
F31 from a previous life
EHM @ 42K, ProVent @ 79K
GDE Eco Tune & TCM @ 46K
Engine mounts replaced @ 55k/93k, Timing Belt @ 90k
Lift Pump @ 97k
OME Lift, 1.5''
Kenwood TM-V71 Ham Radio / Cobra C75WX CB
Surf Racks

I do not see your post with pics!

I cannot see how the tire manufacturers can say that tire size does not determine "rotations per mile" ...so if I drastically lift my KJ and put massive tires on then my speedo will still be accurate?

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2002 Export CRD 2.5 Sport

$425 to replace a tstat Dealer price on the part with gasket is like $150, labor 30 minutes to undo/redo 4 bolts and clean gasket surface and drain/replace a bit of coolant, maybe 1/2 gallon of new coolant if they don't capture what comes out and reuse it.

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Sold to LOST member my 05 Ltd, GDE Stg II turbo + TCM tune, SunCoast TC w. Transgo kit, Steiger window regulators, Samcos, Fumoto valve, 2nd gen filter head with Lub. Spec. bleeder, Hayden clutch & 11 blade fan, inverted spare, P-1 battery, BF Goodrich Long Trail TAs, Etecno1 glow plugs, timing belt at 50K miles/8 yrs

Just curious, what is your $0.39 fix is and where are you located?

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Supporting Vendor and Moderator of LOST
05 Jeep Liberty CRD Limited
Ironman Springs/Bilstein/Shocks
Yeti StgIV Hot Tune
Week's BatteryTray
No FCV/EGR
Samcos/ProVent
SunCoast/Transgo
Carter Intank-pmp
2mic.Sec.Fuel Filter
Flowmaster/NO CAT
V6Airbox/noVH
GM11 Bld.fan/HDClutch
IronrockArms/wwdieselMount
98 Dodge Cummins 24 Valve

Sorry, I haven't had a free minute since the 13th. I am in Michigan, family Washington St., friends in Cal. I used a free large-size paint stir stick to shove a black 33 gallon trash bag (~ $0.39) between the two radiators to block airflow. I laid down in front of the Liberty, and carefully pushed one edge of the bag all the way to the top of the gap, pulled down on the lower corners to even it out. Those are soft aluminum vanes on both sides... Over a few days, I carefully watched temps to ensure that it did not overheat.

I had cardboard sheets covering the fan in front of the radiators, but that did not do much, and airflow was not significantly restricted. I went from 15-19 MPG highway (depending upon fuel mix) to 18-22 MPG. One tankfull of driving in central California reached 25 MPG. One strange over-heat session, I resolved by pulling over, turning off the engine, and restarting immediately. Overheat went away. (I made the assumption that the thermostat started working as expected for that one on/off engine cycle.) 3.5 months later, bag still in place, temps "just to the left" of center on the cluster gauge, gauge never moves to right of center.

The forward radiator appears to be a transmission cooler, and the second the main engine cooler. Pulling a "light trailer" at about 2000 lbs, and a full payload in the passenger compartment, I was sweating bullets that I would burn out my transmission before knowing it was gone. Given the disabled instrument cluster, I was not sure what else besides "Check Engine" was missing. (I'm still not sure.) Since January, no trailer, local driving and 25 mile daily one-way commute mostly Interstate Hwy, 21 MPG.

OBTW, do not replace missing "Check Engine" red normal-brightness LED with "extra bright" blue LED on instrument cluster. Not if you want to be able to see at night. (I have a glow plug error causing light-on condition.)

OBTW, electrician's tape is almost as useflul as duct tape, in a pinch. Attaches to cluster cover without leaving sticky gunk.

The transmission cooler is built into the bottom of the radiator as far as I know. I think what you are seeing is the radiator, the intercooler, and then in the very front, right behind the grill, an AC condenser with the electric fan mounted to it. Your bag trick may be blocking the radiator, but it is probably also blocking the intercooler which may not be helping your cause.

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2006 CRD - GTB2056 turbo by Dieselguy86, Eco Trans Tune, Lift Pump, Week's, HDS Tstat, Racor Filter, ARP's, OME 790's+Top Plate, JBA 2.5", JBA UCA, Moab's+265/75R16, ARB Bull Bar, 4.10's, TrueTracs

Correction - on the KJ CRD the transmission cooler is in the bottom of the AC condensor.

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Sold to LOST member my 05 Ltd, GDE Stg II turbo + TCM tune, SunCoast TC w. Transgo kit, Steiger window regulators, Samcos, Fumoto valve, 2nd gen filter head with Lub. Spec. bleeder, Hayden clutch & 11 blade fan, inverted spare, P-1 battery, BF Goodrich Long Trail TAs, Etecno1 glow plugs, timing belt at 50K miles/8 yrs