When i turn the temperature up or down the temp stays the same which is mainly cold so i gather it is the dccv.
One other thing thing it is building up pressure in the top hose!! i had a head gasket test and came up clear would the dccv be causing this???

 

Most likely the DCCV...

 

Sounds like 2 faults. The top hose one sounds worrying.

I guess check the hoses are routed correctly in case someone's been messing!

Check the aux coolant pump.

Maybe heater matrix is blocked?

 

The DCCV usually causes hot air constantly, so it may not be the obvious culprit.

Is this a new fault? The hose also?

 

That's true of an ELECTRICAL failure, but they plug up just about as often; which means low/no heat. Sometimes fixing that only makes for mediocre improvement. That would mean a heater core [matrix] also, possibly.


Cheers,

 

Hi, if i leave it ticking over for about 20 min i will get slightly warm air but when you ajust to hot or cold it stays the same temp, as soon as i drive down the road it goes clod........ what do you suggest i do? stick it on a computer will that tell me whats going on
And i suppose flush the matrix through with a hose?

(Head gasket)My mate done a test for a good 10 min and the die stayed blue

Thanks Kurt

 

I got the car about a month ago when the weather was warm and it did work slightly but not brilliant.
I released the pressure the other day then i drove the car hard for about 10 miles and know pressure built up so i dont think its a head problem.

Thanks norri

 

Climate control module may have shorted, maintaining her at a mix of cold and warm.

 

Change the DCCV first. When you change it be SURE to use compressed air to blow out the heater core. Then see what you have. Use the Lincoln LS part it is much cheaper. Amazon or RockAuto has it.

Sounds like you might have a combination problem but the DCCV is definitely a wear item and needs to be replaced.

You can check the AUX coolant pump on the bench just don't operate it dry for more than a few seconds. This could also be part of your problem but don't change it yet. Just check it when you change the DCCV. Your in the same area anyway.

Finally has the thermostat been changed and any idea if the coolant has ever been changed?? Is it the correct coolant? Depends on the year of the car.

We need the year and miles on the car for better answers.
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2001.... 82 thousand its done, not sure about the coolant as have not had it that long but it looks lovely and clean and its a pinky colour if thats any help.....

 

Hi guys, new to the forum. Hope this helps. My 2000 was having the same problem. When I took it to the dealer they found out that my antifreeze reservoir had a small leak that kept my coolant/antifreeze level below the level needed for the heater to work. I thought they were blowing smoke up my you know what, but after replacing the reservoir my heater startred working perfectly. Hope this helps.

 

I have noticed in several cars that the first sign of low coolant is the lack of heat.

 

Absolutely! Everyone should take note of that, especially in this day and age of pseudo-gauges that are really not much more than idiot lights. Manufacturer "focus groups" tell them a gauge that goes up and down is "disconcerting". Consequently our "gauges" read normal for anything between 85 deg C and about 115 deg C. Of course that means screw those of us that want our gauge to tell us what's really going on.

Sorry for the rant.

So to sum up.......lack of heat, or that "gee, I've never heard that fan run like that before" kind of voice in your head; means get it checked out! Even if the temp gauge reads normal.

Cheers,

 

I had a Jag bloke checked the dccv and the AUX coolant pump all good, he said my matrix is blocked and the antifreeze reservoir has a pipe missing off the bottom of it?
But it dont use water......

Any ideas for clearing a Matrix??????

 

Well if "Matrix" is a different word for heater core then do what I posted above.

There are 3 hoses going to the heater core and you can unhook them on the passenger side of the engine compartment for USA cars. Then use compressed air to blow everything out. Don't use real high pressure or you might damage the core. Use about 25-30 psi air pressure.

I don't understand missing a hose? Can you explain or post a picture? The S Type has a good number of coolant hoses and they all go to something!
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Can you flush the heater core with a water, or do you have to use air?
I have the same problem on my 2001 S Type 4.0. No heat.

 

Yes you can flush with water, it would be best to flush in the reverse direction of normal flow.

 

Hi James i was wondering if you sorted ya problem yet??
Kurt