I lose heat once i start driving,I dont have the greatest heat at idle either, still working on bleeding it out. I broke the bleeder on the upper hose assembly, but I replaced the whole upper assembly today, so now all my hoses are good and new thermostat o-ring[thermostat and oring from autozone, cheap 7 bucks], went ahead and replaced my expansion tank also. When I had the whole system apart, I flushed the engine, radiator, heater core, and every line, hose. No clogs or debris whatsoever, flowed through heater core like butter. I filled system, bleed from front engine bleeder till it dripped, closed it. Heater core bleeder by the expansion tank is closed for now. I started car, ran till at operating temp, opened heater core bleeder, nothing, no liquid, closed it back up. Ran car up to 1500 rpm 3-5 min, checked bleeder, some drips, ran rpms up again....etc....this cycle when on for about 7 or 8 times till i got hot fluid out bleeder, not much noticeable air. Got heat up to 88 deg F max at one moment, kinda fluxuated up and down but there was heat. I know I should be able to obtain more heat...I'll work on bleeding more tomorrow, or hope it bleeds itself during overnight cooldown.

Heres the problem, everytime i drive it I lose heat completely to freezing cold, but when i put on recirc, i get about 60 deg F max i noticed, dont know if that heat is residual recirc of the cabin or even my breath! lol. Any help would be appreciated.

Note: I have all 3 pipes from the dccv heater valve getting hot running into cabin, with main line getting the hottest, way hotter than the other two. Dccv valve is electrically unplugged for now because I rebuilt it yesterday, both sides were stuck closed, so i cleaned completely and put back together, they were both open so i didnt want to get them stuck down again using the electric selenoid on them so I left the whole dccv unplugged, which defaults to both full open, pure heat. Im going to order the dccv this week and put it in, but for now, I should be able to continue the way I have it set up... I believe.

So is it a water pump that isnt pushing enough when running at higher rpm....doesnt really make sense to me because when im sitting in driveway pushing it form 2000-3000 rpm , it seems to get everything running good, and brings the temp up to the max 88 deg F I spoke of earlier during bleeding , which is less than the rpm I drive at so, I doubt it.

 

I guess we are mind readers??

What car? What year? What engine??
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I just added it to my signature , sorry.

 

I forgot to mention , when i started car to fill it with fluids after hose change and flush , the fan kicked on something fierce a few minutes after it reached operating temp, everytime i would raise the rpms for the 3-5 min during the bleeding process, it would go back down. Now my guage on the dash start cold on start up and goes to half way and stays there during the whole time. Even after bleeding it , it still does it after idling for not too long, at one point I even saw the coolant boiling in the new expansion tank I put in today to I shut of car to wait till tomorrow.

 

Sorry for not helping more! You have done and documented your troubleshooting very well.

Look at this thread as I am leaning towards a burned out CCM? They can be repaired for a decent price. Don't buy one new from Jaguar and I would not trust a used one unless it as been checked for this problem. If you get yours repaired have them add the protection circuits to the CCM. This will prevent the DCCV from taking out the CCM in the future.

https://www.jaguarforums.com/forum/s...l-input-37229/

Here is a nice hand drawn circuit from that thread that might be useful? It shows how to check the DCCV in detail. Have you received the DCCV yet? As you said it should be in the open position without the power plug being plugged in but I am a bit suspicious that all three heater hoses are not the same temperature?? I would focus on getting all three hoses equally hot. Something is blocking your coolant flow at least partially.

They should be if the DCCV is open and there is no restriction in the heater core.



I would remove the grille above the ignition key and clean the in cabin temperature sensor. I also would check all three evaporator temperature sensors.

Does the external temperature sensor read the correct outside temperature?

You have an odd heat problem in that at idle you have heat but not at speed. This is backwards from the normal symptoms and is difficult to trouble shoot.

Finally have you checked that the AUX coolant pump is working?

I also had a hard to fix no heat issue on my 2005 STR and Brutal finally had me flush the heater core again by itself and I started getting heat. You can flush just the heater core be removing the three hoses to the heater and flushing. It's awkward but doable. I also replaced my AUX pump even though the old one seems to still work on the bench?
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Ditto to clubairths' toasted CCM. You're getting heat up to 88 degrees in the cabin at moments but then backs down. The DCCV went south, sending the CCM with it. Disconnect the battery, replace the DCCV, then pull out the climate control panel and unscrew the CCM from the rear of CC panel. Pull off the protective wrap covering the tracers. You'll likely see one or two that are burnt. Resolder them and you may be good to go. An outfit is available that rebuilds the CCM for $120 (check stickies).

 

The S-Type 3.0 V6 does not have an auxiliary heat pump, that is only on the V8 engined cars.

 

Thanks NBCat!! I forgot as I live in V8 land!!

Please disregard the AUX pump remark.
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I will have to get the dccv in first, havent ordered it yet, and Im open to quick suggestion for where to get it.

I went out this morning, fluid in canister was almost to bottom. I filled to cold line and proceeded the bleed proceedure again.

things i noticed...

-same thing with heat going up to a point then back down during bleed.
-this time, i didnt get any fluid out of the heater core bleeder till well after the thermostat opened.
-the three lines going to heater core warm up, but the main line is hot, while the other too are noticeably less, with one being slightly cooler than the first of the two.
-the car gets hot, i have torque pro on my android running elm27, I have it on during all this and watch my coolant temp because my dash one never seems to move from half....it goes up to about 220 before the high velocity fan kicks in, if i raise rpms to 1500-2000 it cools slightly back to under 220 and fluctuates from 208-217, when i let off it goes back up to 220-224F, fan kicked in fierce so this is when i shut it down.
-cabin air temp through blower was 80 at this time
-everytime i turn on the heater at first the A/c comes on
-everytime i turn on heater with auto button a/c comes on
-very wierd....when i turned on recirculation, the air temp blowing out of vents started diving toward cold...the opposite of what I experienced driving.
-and lastly- there is a hissing coming from the top of motor under intake upfront, sounds like air pressure releasing, not sure, seems to be around where the in and out coolant main lines to engine are located...there is absolutely no leaking or wetness I have experienced anywhere ever during this other than the original expansion tank , which i have replaced.

I was trying to troubleshoot with the old dccv default open unplugged for now because i thought it wouldnt be a problem, but it seems it might be relative to some of this, must be restricting again or something because I flushed everything and flow was not an issue anywhere, the heater core flowed perfectly through all three tubes and I reversed the flush too, very clean, clear, no chuncks or crap anywhere. When i rebuilt the dccv , it wasnt even that bad, light gunk, grit and the worn out seals is what made it stick together.

 

Will, did you also replace the cap on the expansion tank? If not then the tank may be losing pressure. Check radiator hoses to and fro radiator/water pump for leaks. Anyway, what you describe in heat then no heat could be a function of toasted CCM. Let's determine the origin of the hissing noice eminating from under air intake.

 

Right here:



I put one of these into my 1999 S-Type recently.

 

Rockauto.com sells the DCCV for $80. Same DCCV as 03 Lincoln LS. Consider this when your pupils dilate on the same exact same Jaguar DCCV that goes for a third more.

 

Not sure where to begin with hissing, I have no leaks. System seams to be full of fluid, dccv lines at least get 80-90F, with the main line getting 100 plus. I have never seen any leaking anywhere.

Cap doesnt seem to be an issue on tank. It has never sounded like its leaking, even when fluid was boiling with engine at high temps. I checked with my ear close to it. I havent seen any moisture around cap under cap on top of tank etc....

 

Hah! Jaguar dealers on this side of the duck-pond will charge you a bowel-evacuating €300 for the exact same Motorcraft-Bosch part with "Jaguar" written on it in crayon! I thought the Amazon price was excellent, particularly as my brother happened to be in a position to hand-deliver it! ;o)

 

heres one on ebay

Ford XW4Z18495AA Heater Control Assembly 5 Port Valve | eBay

same motorcraft brand and part number yg355 even has oem ford number there too. only 73 or so. Of course for 80 through rock auto, that sounds safer to me.

 

they list a yg378 motorcraft for the 03 s type, it looks different , has only 3 ports and different angles and its 92.00.

the one they list for the 01 lincoln ls is the yg355 and its listed at 150.00

where did you find the 80 dollard dccv?

 

Gaaah! We get ridden sidesaddle here in Ireland for auto-parts - I'm sick of it!!

 

See if this helps Link JagRepair.com - Jaguar Repair Information Resource

 

There's a cross-ref of parts on here. Dealers are not often the cheapest for parts, though it can happen. That is not by any means unique to Jaguar!

 

that is the EXACT link I used to diagnose and rebuild my dccv the two days ago. Very helpful, and probably the best write up on the dccv on the web.