I will run that test again in a few days when I get home. Kicking myself for not posting those values originally.

Anybody else want to join in and try the test? I'd especially like to get some readings from a DCCV that is working properly. Nobody ever bothers checking such things when all is well, but that is precisely what will help the most for comparison when there is a problem.

 

If I recall correctly on my 2000 S Type 4.0 after DCCV replacement & aux pump relay connection repair at idle, idiot gauge dead center:

DCCV coolant feed pipes temps around 90 degrees with HVAC set to 65 deg or Lo (solenoids closed) around 130 - 140 degrees with solenoids full open. (HVAC set to 85 deg or Hi)

 

I have some questions...

During parked Manual LO test, both cabin pipes were basically 166°... Why do the L/H vents blow colder than the R/H vents? Shouldn't both sides of the cabin be blowing warm?

After parked Manual LO/HI test, I was sitting in the car with A/C on Manual LO w/Recirc, while finishing notes. I only had air coming from the 2 L/H dash vents & I was freezing. I know this isn't part of the epic thread tests, but... I opened all the dash vents & took IR readings...

L/H 28°
L/C 36°
R/C 65°
R/H 62°

Assuming that at the time the cabin pipes were about equal in temp & much warmer than they should be... Why were the L/H ones blowing so much colder like a refrigerator, while the R/H ones were blowing near the appropriate 65° that the A/C was set for?

Today after a 20-mile trip, the ducts were blowing as they had been... cold on left, warm on right. As soon as I pulled in the driveway, I popped the hood & took readings of the cabin pipes with the IR. The Left Cabin pipe was 165°, while the Right-Cabin pipe (the side that was blowing warm) was 16° cooler at 149°... Why is the pipe for the side that blows warm, reading so much cooler than the pipe that feeds the side that is blowing cold? Shouldn't it be the other way around? The orientation of the pipes are the same on a 3.0 & 4.0, correct?

I was reviewing the 2002.5+ workshop manual for DCCV R&R. It instructs removal of R/H wheel-well plastic splash panel. Can that panel be removed on pre-2002.5 models? It looks like it could make access easier.

I've been using Jaguar Antifreeze (JLM209722). It's expensive. Requirements for this engine: WSS M97B44-D. I see Motorcraft Orange Concentrated Coolant VC-3-B meets that specification. Switching to V-3-B should cause no concerns, correct?

 

At least Havoline red (check label) is OK according to others.

I think people have said Zerex-G05 is OK - again, check the label.

 

Good question about the line temperatures versus the duct temperatures. As you've said, you'd expect to see warm duct temperatures on both sides, not just the one.

Strictly guessing, but maybe it has to do with the coolant flow rate reaching each side of the heater core. The heater core acts like a restrictor, so once coolant leaves each side of the DCCV, it's going to back up slightly in the lines and transfer some heat there.

Based on the line temperatures, it seems both sides of the DCCV are not closing completely. There's probably only a trickle on the cool side, but a moderate flow on the warm side. Both sides can heat up their respective lines, but only the warm side has enough coolant flow to transfer a noticeable amount of heat into the cabin.

That's my best guess.

 

+1 on partial DCCV failure.

One or both solenoids may have coolant intrusion, or solenoid failure (stuck open, closed or partial)

And yes, one side can be affected more than the other. Each solenoid is a separate circuit, per say...

Sounds like you need to get a new DCCV installed.

Don't buy used.

Don't buy a cheapie DCCV

Get a legit Bosch brand, like motor craft.

You'll thank me later. Not a job you want to do more than once.

 

All rightie, I had a little free time today to run the test again.

70F day.

Engine cold, not run for at least 12 hours.

LO selected immediately after engine start.

Ran at idle with hood open until dash gauge centered, approximately 10 minutes.

Next held RPM at 1500 RPM for two minutes, then back to idle. This increases coolant flow in case either side of the DCCV only has a slight leak.

Read approximately 180F at radiator inlet and crosspipe at front of engine (V6).

Both heater core supply lines and the return line read approximately 75F. Measurements taken at the bend near the serpentine belt, away from the exhaust manifold.






Based on your 160F+ readings, I'd say your DCCV is kaput. Change that verified bad part, retest and let us know. Note how my readings were only about 5F warmer than the ambient temperature I had at the start.

For posterity, please hang on to the old DCCV for a post-mortem dissection. Another member recently did the same with his DCCV. Nothing looked horrible, no crud or corrosion, but it seemed the seals had simply swollen in the bores.

 

I got hold of '01 Lincoln LS factory service manuals because DCCV/hoses/pipes, amongst other things, on this '02 S-Type (prod date 6/01) are like '01 LS. I also got a scanner/data logger for Jaguar/Land Rover models.

Following the manual's steps for troubleshooting my a/c's condition, I first scanned for any DTC's in the climate control system. These appeared:

B1966 Output Air Temperature Sensor Circuit Failure
- This is aka A/C Post Heater Sensor Circuit Failure, & Heater Matrix Air Temp Sensing Circuit Fault.

B1342 (Climate) Control Module Internal Failure

Then, I followed instructions of Lincoln LS service manual Test N1: Check Coolant Control Valve... clamping off the 2 inlet & 1 outlet hoses to/from heater core & running A/C full cold for both driver's & passenger's side, obtaining discharge temp from each side.

I took IR temp readings at the outlets before & after clamping the hoses. I also obtained system readings via the scanner. I was supposed to see a change of either the A/C working correctly again once the hoses were clamped, or staying as it's been. It stayed as it's been. This result leads to Test N2: Check Evap Core Discharge Air Temp Sensor

Had the A/C worked correctly after clamping, troubleshooting would continue with Test K which involves checking cooling system, A/C system, module, & sensors. Eventually it leads to either DCCV or electrical fault, depending on results.

Code B1966 Output Air Temp Sensor Circuit Failure, requires troubleshooting with Test E: Evap or Heater Core Discharge Air Temp Sensors Not Operating Correctly.

Coolant leak I mentioned in my first post isn't/wasn't from DCCV. After smelling coolant again, I checked for leaks & found pin hole leak at plastic portion of upper rad hose which sits somewhat above DCCV. It's slightly oozing like blood from a *****'d finger, but I'm assuming back when there were large outside temp changes, the leak was more than an ooze. It dripped onto DCCV/hoses below, & then to the ground.

Using scanner, I checked for other problems elsewhere. In the powertrain control it indicated P0125 Insufficient Coolant Temperature for Closed Loop Fuel Control. Didn't investigate yet.

I cleared stored DTC's, & later rescanned. So far, Control Module Internal Failure has not returned, but Outlet Air Temperature Sensor Circuit Failure has. Monitoring for insufficient coolant temp hasn't had time to complete yet.

I stopped there for now, but I'll have to investigate the sensor circuit problem.

 

I'm not 100% convinced of the logic in the Lincoln manual. I think their test of the DCCV is based on the AC working properly. You may very well have a second problem of your AC not working at full capacity. We don't really know. We DO know your DCCV is not closing fully, based on the readings you took of the lines feeding the heater core.

See post #22: Reading of 90F (unknown ambient temperature) with a good DCCV commanded closed.

See post #27 on my car: Reading of 75F on a 70F day with a good DCCV commanded closed.

See post #16 on your car: Readings of 166F on a 70F day with your suspect DCCV commanded closed.

In post #19, we discussed that your DCCV is responding somewhat (but not fully) to inputs, so it's a reasonable assumption the control circuit is intact.

Based on the high failure rate of the DCCV, and the likelihood that the internal valves are not fully closing, I can't stress highly enough that it should be replaced. You need to fix the known problems before heading off in other directions. Remember, you may very well have multiple faults present, but it's time to first take care of the glaring issue screaming for attention. A fault with the DCCV will dramatically skew other test results.



Definitely fix that. From my limited experience, the coolant flow on these cars is very temperamental if normal operating pressure can't be reached.


Be careful chasing fault codes. I deal with computer-controlled systems like this on a regular basis (in aviation). Please remember, as smart as computers can be, they can also be amazingly stupid. A computer only does what it is programmed to do. Depending how the monitoring logic is written, it's very possible that uncommanded warm air (from a DCCV stuck open) will not be directly monitored, but will skew downstream readings. The computer responds as programmed, and mistakenly tells you the downstream sensors are out of range. Fix the known problem and retest before reading too much into these potentially misleading fault annunciations.

 

+1

and a minor leak may well prevent pressure building to the spec and thus temperatures / flow may be wrong. So, do the obvious fixes (quite cheap) and then re-test.

 

Scanner was correct. Pulled d/s & p/s duct temp sensors. Also pulled evaporator sensor. The d/s sensor had infinite resistance.

DTC brought up by scanner was identified in LS manual as "Driver's Discharge Air Temp Sensor - open circuit". Jaguar Climate Control Training Guide identified code as "Heater Matrix Air Temperature Sensing Circuit - open circuit, high resistance, or short to B+ voltage".

Skipped to next step to check volts at sensor harness-side connectors...
p/s = 4.92v
d/s = 4.93v
evap = 4.66v.

Is evap sensor voltage a concern? Jag's specs are 5v nominal. I can't find minimal spec from Jag. LS specs are 4.7-5.1 volts.

If it is a concern, next step is checking resistance between evap sensor harness-side connector & CCM...

Had the earlier code for Climate Control Module Internal Failure, but it hasn't returned. Is it possible the bad DCCV damaged CCM, driver side discharge sensor, & may be causing low voltage at evap sensor connector, even though only one side of valve is partially failed? Is this the sort of damage that occurs on later models, or no?

I replaced bad sensor, & no longer get DTC for it. No DTC's for Climate Control, at this time.

Since I'm going to replace upper rad hose, I'll do DCCV at same time. Should give better access & no waste of coolant...

I'll be switching from Jag branded antifreeze to other brand that meets specs. Should I flush the system, or is there no harm in just draining, then refilling after job?

A/C season is ending. Heat comes out equally. Data stream readings for discharge sensors are equal, & vent IR readings are equal. Is there any harm in running heat in the mean time?