Time for a new DCCV?

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theophile

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'02 V8. I rarely have passengers so therefore usually have the temp set for the same on both sides. Yesterday I went to Gulfport (joegr's neck of the woods) with a colleague who likes his air a little colder than I do. At the end of the day, after I dropped him off at his house, I was pulling out of his driveway and felt the air coming out of the driver's side vents suddenly become very warm. It now blows hot on the driver's side but nice and cold on the passenger side.

I know this is a classic indicator of DCCV failure. But the only reason I haven't already ordered the new part is because every thread I've read here about this issue, the symptom is the opposite of what I have going on. Normally, the poster is complaining about the driver's side blowing cold and the passenger side blowing hot. Here's what I've done to narrow this down to DCCV:

* I did the DATC self test and it passes with no codes. There are also no continuous DTCs registered.
* I monitored the A/C sensors with a scantool, and it shows the driver's heater temp and the passenger's heater temp having a temperature differential of around 20 degrees C at operating temperature, suggesting it's not a temp sensor malfunction.
* Starting the car cold, monitoring the live sensor data, and setting the controls to 60 degrees, I can see the A/C core temp at around 3-4 degrees and the driver's and passenger's heater temps start out at about the same value. The air coming out of the vents feels cold and about the same temperature. As the car warms up, the driver's side temp sensor climbs noticeably faster than the passenger's side, which coincides with the vent air getting warmer.
* There don't seem to be any coolant leaks, although the coolant reservoir does appear to be a bit on the low side. I will check it again in the morning when it's stone cold.
* There are no readily apparent signs of refrigerant leak, although I did not inspect very closely because the A/C system does appear to be cooling the air, it just gets overpowered by hot air on the driver's side.
* Fuse #1 is not blown.

Again, I realize that all this points to the DCCV, but I just wanted a sanity check because I haven't run across another thread where someone has heat on the driver's side but cold air on the passenger side. Then again, if the DCCV is going to fail and cause one side to stick open, I don't suppose there's a reason it would only be the passenger side of the valve.

Anyway, I'm about ready to order the DCCV but if you think there's something else worth checking first, please let me know. And on the subject of ordering, does anyone have anything good or bad to say about the "Four Seasons" brand part?

Thanks all!
 
There are two valves in the one assembly. Either one can fail first. It had nothing to do with your passenger's temperature selection. (Both valves open and close a lot either way.)
I can't speak to Four Seasons. When the one on my 06 failed, it started leaking pretty badly at the same time. I needed to replace it that day, so I went with the Murray part that I found locally. That was only a few months ago, and just last night I got a couple of blasts of warm air. I think I will go ahead and order a Motorcraft valve to have handy when the Murray fails.
 
Thanks y'all. I ordered the Motorcraft and it will be here Wednesday. Interestingly, I'm about to do a bunch of suspension work and I've seen that the front sway bar bushings are easier to replace with the DCCV removed or at least out of the way. So at least there's a silver lining!
 
Take note that the bracket to which the DCCV is mounted on comes loose with two bolts, one of which needs to be turned out completely and the other simply loosened to slip the bracket from it, the part where (I think it's the top bolt) the bracket mount hooks and hangs on said bolt.

One bolt goes through hole in mount,
other bolt, the mount hangs on, can be lifted upwards to unhook. (swivels a bit also)

IIRC ...
 
BigRigLS said:
Take note that the bracket to which the DCCV is mounted on comes loose with two bolts, one of which needs to be turned out completely and the other simply loosened to slip the bracket from it, the part where (I think it's the top bolt) the bracket mount hooks and hangs on said bolt.

One bolt goes through hole in mount,
other bolt, the mount hangs on, can be lifted upwards to unhook. (swivels a bit also)

IIRC ...
Click to expand...

Thanks, that's good intel. I went to the Pull-A-Part yesterday to look for a liftgate for a Honda Odyssey, and while I was there, I looked over a few LSes they had. I poked around the DCCVs not to purchase one (obviously) but just to put hands and eyeballs on them and see how they were attached. It sure is a lot easier to see where things go in the engine bay when half of the components are removed!
 
Any 1st GEN Inner tail lamps there? LOL
~ still looking!
 
Well that was every bit as unpleasant as others have said. I had intended to clamp hoses so as not to have to drain the radiator. Then I opened the hood. With that upper radiator hose where it is, I couldn't get at the auxiliary pump let alone the DCCV. The only way I could see to do it without losing my sanity was to start removing hoses, which meant draining the radiator.

I also read the tips about not using the quick-disconnect couplings on 3 of the 5 hoses, but even with the fancy cable-based hose-clamp pliers, I realized that trying to remove all 5 hoses at the DCCV was going to be incredibly difficult.

So I disconnected the upper radiator hose at both ends. It has a T that runs to the DCCV so that also served the purpose of freeing up hose 1 of 5. With that out of the way, the aux pump is very easy to dislodge with two bolts. Lifting it up and out of the way also makes it easy to remove hose 2 of 5, which runs from the DCCV to the aux pump. That left the other three hoses, which have the quick disconnects. Even at this point, there was too much stuff in the way for me to be able to get at the hose clamps on the DCCV side, so I just took my chances and quick disconnected them.

A note about the quick disconnects: For each of the upper two fittings, there are two o-ring gaskets that sandwich an amber plastic spacer ring. These plastic rings tended to slide off. I bet that failure to notice theses things or put them back on could result in leaking.

Anyway, with all those connections undone, it was just a matter of unbolting, removing the electrical connector, and maneuvering the thing out of its cavity.

Here it is in its liberated state:

20150509_150556.jpg

While I had it out I went ahead and replaced the front sway bar bushings, which was its own adventure. After putting everything back together, I went through the coolant fill and bleed procedure. Everything seems to be working great again, and I have my A/C back!

20150509_150556.jpg
 
BigRigLS said:
LOL, fun huh!
Click to expand...

In a manner of speaking. I was tempted to posts pics of the cuts, scrapes, and bruises all up and down my arms but decided against it. I will say that I am very proud that I was able to get a torque wrench on all the bolts with torque specs (this mainly applies to the sway bar bushings replacement). Of course, this required some of the ugliest chains of wobble extensions I have ever constructed.
 
Yeah I recall the good times on the inside of my left arm, it was the radiator shroud plastics.
 
Tell me what a "DVVC" is. Monday on our way home from Myrtle Beach I started getting heated air out of the drivers side and cold air out of the passenger side. Had to come home with no air. Talked to a mechanic and he said it was a "flapper motor", does that sound correct?
 
1LoudLS said:
not at all...

that is as classic of a DCCV failure as it gets...
Click to expand...

As it gets... what?

Sorry I didn't read your reply with my brain working. So it sounds like I have a bad DCCV . From the picture it looks like a pain the ass to get to. Whats the cost? Thanks for your help.
 
that is more than likely your problem, but i'll hold judgement until joe gets
in here and confirms it ;)

1loudls is saying, your example doesn't get any MORE classis than the typical
failure of the dccv.
 
Yes, DCCV (Dual Coolant Control Valve).
No, the LS does not use a flapper to control temperature like many other cars. If you are going to use a mechanic, find one that knows at least a little bit about the LS.
The DCCV is not that hard to change out.
 
it is my under standing that there is only one refrigerant heat exchanger under the dash that cools the air... but there is a separate heat exchanger (two separate coolant loops) for each side to heat the air individually with each side being controlled by one half of the the DCCV.

so if you are getting cold air from either side, then the AC system is working fine, but if either (or both) sides are also being heated and the DATC is set to a low temp, then the DCCV is stuck open allowing hot engine coolant to pass through (in this case) the drivers side coolant/heater's heat exchanger.



for instance, if it is hot out side and you have the drivers side set to 70* but the pass side set to 76*, the DCCV allows a little hot engine coolant to flow through the pass side to warm that side up a little bit after it has be ran through the AC.
 
joegr said:
Yes, DCCV (Dual Coolant Control Valve).
No, the LS does not use a flapper to control temperature like many other cars. If you are going to use a mechanic, find one that knows at least a little bit about the LS.
The DCCV is not that hard to change out.
Click to expand...

Yes this guy does not know anything about the LS. How do I find someone other than the damn dealer?
 
i'd take it to a dealer. at least they'll use a factory released manual, and you can take
it back if something happens.


...but that's me.
 
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