04 XJ8 101K Miles -- Cooling System Issues -- Heat Gets Cold --
#21
Not sure if it is the same issue, but my thermostat was stuck open on my car and if stopped, the heat worked ok, but when on the highway at speed (with all the cold air through the radiator) no heat. It eventually set off a CEL. $20 part and should be an easy swap (mine still has warranty). Probably worth a shot.
I think you might have a different issue, namely, a coolant leak. I know you say the res is full, but the pressure loss so quickly after parking is suspect to me. I have been working on cars for eons, but new to jag so I am not sure what the most likely suspects are. If it were a land rover I would know where to look.
I think you might have a different issue, namely, a coolant leak. I know you say the res is full, but the pressure loss so quickly after parking is suspect to me. I have been working on cars for eons, but new to jag so I am not sure what the most likely suspects are. If it were a land rover I would know where to look.
I have great heat at all speeds all the time; until the temp guage fluctuates and then things go crazy. Mine is usually opposite from yours, I'll have heat when accellerating, and cold when at a stop. I'm thinking a sticy thermostat in the closed position.. Possibly.. Was hoping for a few more ideas before I start throwing parts at it. The T-Stat is $60 from AutoZone. Thanks!
#23
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randyshear (11-29-2012)
#24
Yah steve, I was pretty confident a hard reset would do the same thing, but i've recently learned (through motorcarman and others) that it does not, must have the IDS/SDD to clear the adaptations, and/or update the programming. It seems sometimes that it works, but the hard reset clears the fuel trims and other ECM behaviours, that often messes with shifting...but only for a short time, and long-term adaptations return eventually.
Not just a jag dealer, but anyone with SDD and a real (or cloned mongoose cable) can do the same procedure at home. Cleared my xk8 a few weeks ago when it was in the tranny shop getting some new guts. More and more of us are investing the $200-$500 for the very same tools the dealer has.
Not just a jag dealer, but anyone with SDD and a real (or cloned mongoose cable) can do the same procedure at home. Cleared my xk8 a few weeks ago when it was in the tranny shop getting some new guts. More and more of us are investing the $200-$500 for the very same tools the dealer has.
The following 2 users liked this post by H20boy:
randyshear (11-29-2012),
steveinfrance (11-29-2012)
The following users liked this post:
randyshear (11-29-2012)
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#33
UPDATE:
After flushing the cooling system several times, I haven't had any more issues with the heat going cold on me. I took the XJ8 to a local "garage" and had them do a transmission flush using Castrol Multi Import fluid. At first I had erratic shifts, and harsh shifts.. I was very upset, but I'm happy to say that more than 1,000 miles in 2 days on her she is so much better. The "lurge" from 2-1 is almost completely gone, but still there on occasion. I am at Scholfield Auto Plaza in Wichita, KS and they are reflashing the TCM, and adding any fluids if needed. I'll update more after the car is returned to me. FWIW Scholfield is VERY reasonable on prices ($75 to flash the TCM), loaner cars if needed, huge customer waiting area with free Wi-Fi, free "courtesy work stations", free coffee, soda, etc. Very friendly!!
After flushing the cooling system several times, I haven't had any more issues with the heat going cold on me. I took the XJ8 to a local "garage" and had them do a transmission flush using Castrol Multi Import fluid. At first I had erratic shifts, and harsh shifts.. I was very upset, but I'm happy to say that more than 1,000 miles in 2 days on her she is so much better. The "lurge" from 2-1 is almost completely gone, but still there on occasion. I am at Scholfield Auto Plaza in Wichita, KS and they are reflashing the TCM, and adding any fluids if needed. I'll update more after the car is returned to me. FWIW Scholfield is VERY reasonable on prices ($75 to flash the TCM), loaner cars if needed, huge customer waiting area with free Wi-Fi, free "courtesy work stations", free coffee, soda, etc. Very friendly!!
#34
UPDATE 2:
Ok, so they are finished. They gave me a free 140 point inspection, most everything is ok. Needs some minor suspension work (mainly just ripped tie rod end boots, and ripped ball joint boots), tranny pan and connector seal are leaking a little bit. Tranny was 2 1/2 qts low.. (just had it flushed and filled a few days ago, so it appears the shop didn't fill it properly. The tranny leak is small, never any drips on the garage. Just kinda "damp" pan. He had 1 1/2 qts in his cabinet and gave it to me free, only charged me for 1qt. (THANK YOU MASTER TECH!!) TCM reflashed, ECM reflashed, free car wash. This place is absolutely amazing! I'll update after the car relearns everything. The master tech said it'll take about a week to get the ECM and TCM adjusted again. He advised it might be a little querky for a bit lol.
Ok, so they are finished. They gave me a free 140 point inspection, most everything is ok. Needs some minor suspension work (mainly just ripped tie rod end boots, and ripped ball joint boots), tranny pan and connector seal are leaking a little bit. Tranny was 2 1/2 qts low.. (just had it flushed and filled a few days ago, so it appears the shop didn't fill it properly. The tranny leak is small, never any drips on the garage. Just kinda "damp" pan. He had 1 1/2 qts in his cabinet and gave it to me free, only charged me for 1qt. (THANK YOU MASTER TECH!!) TCM reflashed, ECM reflashed, free car wash. This place is absolutely amazing! I'll update after the car relearns everything. The master tech said it'll take about a week to get the ECM and TCM adjusted again. He advised it might be a little querky for a bit lol.
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