Jaguar S-Type DCCV

This procedure is related to a no heat to the driver’s side of the car.First let me say I read several posts on this problem prior to my getting involved in it. I then posted my problem looking for additional information and direction.

What I found is that the heat in the car was about 20° cooler on the driver’s side with the control panel set to 85°. I went to the DCCV and checked the temperature on the three heater tubes going back to the firewall. What I found is that the two feeds going in were about the same and the return tube was in the same temperature range. Bottom line it did not offer any help to evaluate or pinpoint the problem. My thought was that it was electrical so I checked fuses to the entire heating/coolant system and found no problems. I then went to AllData and it offered little to no help in trouble shooting, I then went to http://jaguarclimatecontrol.com and they had a lot of information but I was not ready or convinced it was in the control module or sensors or control valves. In the meantime I wanted to better understand the coolant/heating system so I began to draw out the system, the drawing in any of the references were not like what I had in my car. I will provide my drawing and the factory drawing as an FYI for you. I then had a recommendation to unplug the DCCV and see if I had heat. The information provided was that the DCCV in a relaxed mode (no power/control) is a wide open heat mode. With the plug removed I had the same results, no heat to the driver’s side. At this point I replaced the DCCV. I was a little apprehensive that the DCCV was the cause until I took it apart and found out how it worked. I had visions that it was a clogged heater core and that was not the case.
Electrical diagram to the DCCV:


The power plug to the DCCV. It is a little hard to get to and not easy to remove. Be patient and take your time.

The information below is my procedure to replace the DCCV and the evaluation of the valve and what I found to be the cause.








Installed the DCCV and all was good. Heat again!!




What I did to bleed the system was to open the bleed valve at the coolant expansion tank. I did not open the other bleed valve because it was said you may cause damage to the valve and plastic pipe.

I am also providing another link on my page about replacing the DCCV and bleeding the system.
I hope this helps.

 

I didn't see anywhere which engine etc but I reckon you've a 3.0 pre-2003. The system changed then.

 

Yes this is for s-type pre 2003 3.0 engine

 

hi i have 3.0 ltr s type se on a 99 plate. i have no heat just cold air bothe sides, i took the dccv off had a look at it with the help of the pictures above, took the valves out to see if i could free them up . when they are out of their housing there seems to be a lot of movement but when they are put back there seems very limited movement. very hard to get anything on them .... anyway put a hose to the inlet and managed to get some water through them when under pressure so thought maybe ok so put it back on car but still no heat..... the pipes upto the valve nice and hot but on the other side limited heat. upto the rubber hoses for the matrix along bulk head. any ideas ? would limited flow through the valves stop all heat reaching the cabin or would i still get some heat?

 

Nice write up!!! Kudos, I'm sure this will help many owners now and in the future.

 

It is a good write up, but it's a cut and paste from Gus's site isn't it?

JagRepair.com - Jaguar Repair Information Resource

 

It is Gus's site by a new name

Have a look at the About Me

 

Any special About Me?

 

Well I'm guessing Gus thinks it's special....

 

I'm sure he does, and I would agree with him.
Has he had some kind of input into this thread?

 

By proxy at least, depends on who the OP jag-pilot is.

 

Mmm!

 

Wow, I'd no idea you looked like that!

 

Damn! Do you think I can get a refund?

 

You paid to look that way?

hmm, call it a learning experience.

 

You're right Norri - is the OP in fact our friend Gus?

 

Hmm! That sounds like my work, it looks like my work, oh it is my work links and all!

 

Anything on replacing the DCCV on a '04 XJ8?

 

If there is it'll not be in this forum, which is for the S-Type...

 

I am the real author of the information in this post for the DCCV and it was for S-Type cars. I have not seen any info on the XJ DCCV in fact I did not know the XJ had one.