Jon, I have been thinking about the DCCV and correct me if I am wrong it seems that our northern friends seem to be having the replacement issues. I think only one of us southerners has had issues. I may be mistaken though.

 

Jon,

Just did mine Sunday actually. I'd say in total, on a lift, with air tools (just for removing the wheel) about 2 hrs start to finish. The job books at 2.8 hours flatrate.

No HVAC issues at all.

I got my car from the dealer auction - my brother has a used car dealer license.

When I got the car, it had a cracked expansion tank, like they all do lol... There was coolant all over the passenger side of the motor, including on the DCCV so I really didn't think that much of it. Redid the coolant expansion tank, and went on with life.

Initially there was a bit of coolant still dripping from the car, but I chalked that up to the mess the expansion tank had made. About a week after that, I got a low coolant warning. Added a couple pints to the expansion tank, and it was fine for 3+ months. Then I got another low coolant warning, but no perceptible leakage. (There was dried coolant all over my DCCV). Once again, topped it up, went about my business.

THEN... the weather got nicer, and the heat wasn't on all the time. Within a week, I had another low coolant warning, and some drips of coolant under the car. Once the A/C went on, the drips turned into a puddle, and there was an obvious coolant smell to the car. And then that's when I really started looking into it, and realized the DCCV was leaking.

MY take, I think the plastic on the bottom of these valves fails... If it's going to fail in the mode of externally leaking. Now when the heat is on, the valves are open, at least partially, so there isn't much of a buildup of pressure due to the valves being open. Remember the coolant system is pressurized. When the valves are closed there is pressure there, so what was a small drip turns into a pressurized leak...

SO I ended up replacing it, and so far all is well again...

George

 

Rick, I hadn't thought about it in terms of geography. But perhaps you are on to something there. Salty roads? The undertray should protect the DCCV from that. Running the heater more due to colder weather? I don't know about that since Jan runs the heater pretty much all winter long here. Not using coolant that meets the proper specs (Ford M97B44-D)? That seems more likely. Our S-Type has the official Jaguar coolant in it now and I presume it always has. Prestone's Dex-Cool also meets those specs - I use that in Jan's Lexus RX330 but have never added it to the S-Type....

I hope your theory is correct. Maybe this failing DCCV issue is strictly a northern climate problem. I'd like to see what Brutal has to say about this....


George, great explanation of who/what/when/where in your post. Pressure in the lines probably does have a lot to do with these DCCV failures. But obviously, the components within them are weak or faulty. I hope the new ones are built better. I guess we'll eventually find out....

 

I dont think its road salt... Mine had no traces of it on there. Plus it seems it's the plastic to metal union that seems to fail.

What I think is the culprit here, especially with these ABS type plastics is heat cycles.
When you have a piece of plastic that's exposed to consistent freezing weather on one side, and 200 or so degree coolant on the other side, then cool down, heat up repeat. The temperature extremes would have a LOT to do with the failures being more common.

Btw these BOSCH DCCV's do this same exact thing in BMW's too... BUT there they tend to have solenoid failures, not casing failures that lead to leaks. They are mounted on the firewall on the BMW's.. Wonder if that makes any difference.

George

 

interesting theory as well.

 

It sure sounds to me that the DCCV problems would be resolved if the supplier would build the entire exterior casing out of metal with no plastic involved. For a valve this costly, I don't think that's too much to ask....

 

BTW I have to go to my brother's shop to pick up the old valve to take it apart to see how it failed, Out of curiosity more than anything else.. but the writing on the actual valve is EXACTLY the same whether it comes out of a motorcraft box, or a Jaguar one, or off my actual Jag. The bad news about that is that this is the same DCCV that came out of it. I don't think an upgraded part was ever offered that superceeded the original part, unlike the Oil pan gaskets, which were revised, at least by the aftermarket manufacturers over the years.

I agree an all metal housing would be ideal, as unions between dissimilar materials subject to heating and cooling cycles tend to fail (just look at when GM started putting aluminum heads on iron blocks).

The thing is.... Take this valve (among other things that I've sourced), 164.00 Ford List price, 300 or so Jag list price. Other than the cardboard box that says Jaguar outside, and a part number that starts with X instead of Y, and possibly walking on carpet to the parts counter rather than linoleum what is the difference?

The valve can be had for under $100 if ordered online. I paid 131.94 for mine, from the Ford dealer with my brother's shop discount (20%). Just because he was the only one who could get me one on a Saturday afternoon. This valve probably costs Ford / Jaguar under $50. But they don't want you to know that part. I'm not surprised that It's not made fully of metal.

I still say (I said this with the intake manifold gaskets) we should have a stickied thread with confirmed and tested Ford / Jag Cross Referenced parts....

George

 

+1 on that (you're doing a good job, thanks!)

 

Does anyone have a feel for the most common problem with the DCCV and the underlying cause of that?
- Mechanically stuck valve? (coolant sludge?)
- Electrical - solenoid or wiring? (abraision?)
- Leaking gasket? (poor gasket mat'l seems reasonable)

 

I'd say either a leaking gasket or seal failure between the top and bottom half of the valves, OR a failure of the bottom half abs plastics due to heat cycle fatigue. I'm going to disassemble mine and see if I can track down the source of the failure.

That would cover the leaking ones. I really don't know about the electrically failed ones. Seems to me the solenoids fail, often shorting the transistor outputs and burning ground traces on the A/C control panels. An external wiring failure seems unlikely.

George

 

+1 on that.... Funny thing is the stuff that people think cross over to the LS don't and the stuff that no one seems to look up does. I wouldn't be the least bit surprised to find out that a lot of the under hood parts match up. That is where the economy of scale worked with the Jag and Ford marriage.

Oh, and the price thing...Hell, they all do it... Ask anyone who has a Porsche 944 or an Audi A3???? (Porsche shops VW or Audi....Audi shops VW). Wonder how many Fiat parts are on a Ferrari or Maserati?

 

It has been stated here that the electrical failure is also caused by a leak. So, the different material thesis sounds about right. Some get an internal leak that shorts out the unit while others get an external leak (or seep in my case). BTW I never looked into shared parts on that since my stuff has all been warranty so far..

 

I'm surprised no one has come up with the LS DCCV before. Considering how much banter there is concerning their failures on this site. I wonder if the internal seals on the solenoids fail allowing coolant into the electric actuators.

Btw, My Oil pan was weeping a bit from the gasket. BUT I realized that some of the bolts were loose, I had a similar thing happen in a BMW I used to own. I snugged everything up, cleaned it all, and applied a bit of RTV around the seal where I could. I know I probably have to do a pan gasket eventually, but I didn't have time, and I guess this was better than nothing... SO far no oil drips, but it's amazing what the belly pan can hide...

George

 

Don't I know that...
this is a picture a day after we purchased our S, I was just checking things out and..........

BTW George changing the pan gasket isn't all that difficult, best advise on that is to raise the motor rather than dropping the sub-frame. Also do it when you are doing a routine oil change, why waste the money.

 

The DCCV will fail regardless of where you car is operated. On the Lincoln LS boards it appears to be nearly 100% of the cars will at some time need this replaced. I did my 2003 LS at 62K miles (heating and A/C problems) and my 2005 STR at 54K miles (slight leak and orange stains at the DCCV).

From the LS forums it seems like the coolant carries debris and small grit which settles in the solenoid area. As the valve opens and closes this grit damages the rubber seals. Eventually coolant enters the DCCV and shorts out the electrical side of the DCCV. Now several guys on the LS forum have taken the DCCV apart cleaned it out and reinstalled it. This will work for a while. I don't think the heat cycles have anything to do with it. It does seem that changing the coolant and flushing the system will delay the problem. I took my old DCCV apart from the Lincoln and this is exactly what happened to it.

The LS does not get the A/C module shorting problems like Jaguar does. I have never seen a LS need to replace the head unit because of a DCCV problem.

You might check RockAuto they carry both Motorcraft part numbers. Good service and be sure to get the current discount coupon for your order!
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The externally leaking ones fail in a different way. Somehow they are spilling coolant OUT of the valve. Either from the seal between the ABS and metal portions of the valve, or from a crack somewhere in the valve. Somehow coolant is making it to the outside, initially slowly, and sometimes in large amounts...

That probably makes sense as far as how coolant gets into the electrical side of the solenoids and shorts them out.

George

 

I'll suggest again that everyone should do a visual and white paper napkin-wiping check of their DCCV every weekend as a part of checking your fluids and tire pressures. The same goes for V6 3.0 engines still running the original yellow factory IMT O-rings. Both of these tasks only require about 15 seconds and can save you some serious money down the road by catching these failures early....

I realize that a white paper napkin wipe of the DCCV's casing will probably help you discover only the external leak issue and not the internal leak one, but it's still better than ignoring your DCCV until it's too late....

 

The internal leak will generate HVAC Issues quickly... Fortunately it seems as though anyone with basic soldering skills and a brain can salvage the A/C Control Module if it's too late - rather than spending $$$$ on a new one. I'd certainly be willing to fix them for people.

I'm guilty of Ignoring the IMT O-Rings as well I know I need to do them but time seems pressing, and although there is some oil traces on the heatshield, the car just doesn't appear to be losing any significant amount of Oil.

I'm going to have the Intake manifold come off SOON, to do Plugs, (should I swap coils? at least on the buried side?) and the IMT O-Rings.

George

 

George,

I believe that changing the IMT O-rings can help you avoid misfire issues. And we all know what continuous misfires can do to the catalytic converters. The two O-rings are less than five bucks total. It's the cheapest insurance you'll ever do to your car, and you don't have to take the intake manifold off if you go the short route....

 

Actually the internal and external leaks are from the same set of seals. It just sometimes leaks more one way or the other. Not sure why or how??
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