DCCV in 2002 LS V6

+1 for a DCCV causing an air conditioner performance issue in a 2002 LS. I tackled my wife's last night and the DCCV appears to have fixed the issue.

On hers, the A/C blew very cold when set to 60 degrees. However, with an ambient temperature in the 80's, a temp setting of higher than 66 degrees would cause heat to start blowing.

I performed the climate control self test as well as connected my scan tool to the car and queried the system. No faults. The datastream for the climate control system was interesting as well. The ambient air temp sensor was reading accurately as were the various in-car temp sensors. I also checked the position sensors for the doors and they were all reading what I would expect. After doing some research here and on some other forums, I decided to try a new DCCV, even though I was not noticing a difference from the passenger side to driver's side.

When I got the new one installed successfully, I decided to tear apart the old valve. What I found was that apparently if was sticking due to coolant making it past the seals in the solenoids. Both solenoids had traces of coolant in them, even though it appears they are not intended to be immersed in coolant. Also, some of the coolant appeared to have caused one valve to stick, which is probably why at a setting of 60 degrees, the valve was able to close, but during modulation, the valve would heat up and stick in the open position, allowing coolant to pass to the heater core.

What I don't understand is why, even though only one valve appeared to be sticking, the temp from both driver's and passenger's side seemed the same.

From the short amount of driving the car and getting the coolant up to operating temperature, the DCCV appears to have fixed the issue, but I'm curious if there's something that can be done to prevent this from happening in the near term. The coolant is in good shape, and there was not a build up of silicates or similar in the valve assembly. Has anyone had good luck with Water Wetter or other cooling system additives not causing futher DCCV failures?

-Rod

Thanks Shorod for posting that

My 01 LS has the exact same issue, where is the DCCV located and how hard was it to R&R?

The DCCV is located on the passenger side front of the engine compartment, below the ABS pump near the radiator. It looks worse to change than it really was. It took around 2 hours to change out. Getting to the mounting bolt and nut was a lot easier once I took the small splash shield out near the front mounting location of the passenger lower control arm. Also, it took me awhile to realize that moving the red tab on the electrical connector was actually exposing a thumb button rather than being the connector retainer by itself.

The most painful part was paying the $160 for a new one.

-Rod

where did you get the part for $160? Lincoln is telling me almost $500 for a new DATC unit....

where did you get the part for $160? Lincoln is telling me almost $500 for a new DATC unit....

I believe that the $160 was from the DCCV (Dual Coolant Control Valve aka heater valve), not the DATC control head.

Correct, the $160 was for the DCCV.

I happen to have a DATC in the garage that I bought off eBay as a spare. The wife recently traded in her 2002 LS for a 2010 MKZ so it's just sitting there.... I think the DATC is different between 2002 and 2003 unfortunately, especially if you have heated and cooled seats.

-Rod

Yes, I have heat/ac seats. I'm getting the DCCV & the DATC mixed up.
Just a few more questions before I get back to work on my car
The DCCV is next to the radiator & fan correct? where is the DATC?
Does anyone have a picture of teh Heater control valve? and where it is?
Thx for all the help guys

The DACT is the HVAC control for your car!
Yep! The DCCV is next to the radiator, and the electric water pump.

Dont forget to check the fuses & relays for the DCCV, and the water pump.

A bad coolant bleed procedure could cause No HEAT, see http://www.Alldata.com

Yes, I have heat/ac seats. I'm getting the DCCV & the DATC mixed up.
Just a few more questions before I get back to work on my car
The DCCV is next to the radiator & fan correct? where is the DATC?
Does anyone have a picture of teh Heater control valve? and where it is?
Thx for all the help guys

The DCCV is the heater control valve, and it is next to the radiator as you say.

The DATC is the thing with the buttons and the temperature displays, below the radio and above the ash tray.

How about one LS for the summer, and the other for winter!

I'll have to try that after I win the lottery this week....I guess I'm still wondering why Lincoln told me my DATC was bad when it's not.. Makes you winder if they'd have told me that after they fixed it.

They may have been giving you a "worst case" estimate so that, if you opted to have them perform the work, you'd have been very pleased to get out of there with "only" a $500 bill rather than the $800 or more they quoted you.

-Rod

Just finished. I took the valve and all the hoses off. It looked like hard clay in all of it. I had to take a screw driver and dig it out. It really felt like hard clay. Have you heard of this before? I've never put anything in my radiator before...

Has a previous owner maybe put some stop leak in? Was the color dark, or was it more white? If more white, that may have been silicates that built up from not changing out the coolant regularly or from using tap water rather than de-ionized water. I'm making guesses here based off what I've heard others say, I'm no chemistry expert. Hopefully a similar build up is not in the heater cores.

-Rod

How many miles are on this car?
Was the coolant & flush on schedule for change?
Was this car using orange or green coolant?
Whats the normal life of a DCCV?

The age of coolant might be more of an issue, than mileage.

I would consider a flush with old parts, a new DCCV, water pump, and thermostat.

A good premium green coolant, might have a better rust protection aginst mix metals.
50/50 mix by the gallon is better, than using 50% tap water!

The car had only 20k on it when I purchased. I have 125k on it now. I don't think the dealer ever flushed my radiator during services. I also don't think anything has ever been aded to it (stop leak). That was my first thought as well. The stuff in the lines was light brown and hard as clay. It took me hours just digging this out of all my hoses connected to the DCCV. Now it's clean and still blows cold so it must be the DCCV. I'm back @ square one now. It could also be my heater control valve. Evereything looks the same under the hood so I can't distinguish where it is. Any ideas? Thank you again for all of your help.
FYI, this clay buildup had completely blocked the DCCV and all the hoses attachted to it. It seems like it didn't get into the motor etc though. So it must have started just recently but that's what is so strange cause I haven't added anything to the radiator.
If oil and radiator fluid mix will it turn hard?
Thx again
JP

Did you bench test the DCCV, when it was off the car?

0volts/12volts is used to trigger both solenoids to open or closed!

12volts, if you apply air pressure with a cupped hand on the water inlet, the air shouldn't come out of both outlets.

0volts = The air should come out of both outlets.

I had to use WD40 , clean, 12volts + mussle the solenoids to work again!

The DCCV is a Dual electronic contol solenoids for coolant, the pistons can get seized, and the DACT loses control.

Like a bad fuel injector, or spouse!

Just because you got a signal + sound doesn't mean that it's working.

Do a LS forum search tool ''DCCV'' ,not thread.

Goggle ''Troubleshoot LS DCCV''

... Now it's clean and still blows cold so it must be the DCCV. I'm back @ square one now. It could also be my heater control valve. ...
Thx again
JP

The DCCV is the heater control valve!

The DCCV is the heater control valve, so you don't need to spend any time looking for a heater control valve.

I've never heard of oil and coolant forming a hard substance.

The DCCV solenoids actually close the valves when voltage is applied, so no voltage would be full coolant flow if the DCCV is working properly. However, if the hoses really are all plugged, you won't get flow and therefore no good heat. As you suspect, the build up may be preventing the solenoids from moving properly.

-Rod

When you trigger the dccv with 12volts, the build up of gunk will cause one or both pistons toget stuck in coolant off pos. ''No Heat''

In most cases, it looks like neglected coolant services, it's once every 5years!

Thanks for clearing the air for me. That wasn't very smart of me.
JP