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2 Posts
Discussion Starter · #1 ·
Hi yall!
New member here and first post but I have been reading on here since we bought our car in Feb of this year. This car has been one thing after another since we got it. That being said, the main issue is the one that I’m posting about here. Sorry if this is too long!

Car Details: 2006 VW Jetta TDI 1.9L Automatic- manufactured in 08/2006 so I think that makes it the MK 5.5?

Bought the car in Feb 2022 and it had a coolant leak. We quickly determined that the leak was caused by a major split in the upper heater hose (part number 1K0-122-157-HP) that connects to 1K0-122-291H and that it needed to be replaced. Since our car was manufactured after 07/2006, the actual dual hose set up was a bit pricy so we purchased a gates hose in the correct size for just that side with a 90* bend on one end and hooked it all up.

At the end of April, the leak returned. This time though the coupler (1K0-122-291H) was shattered so we ordered a new one and replaced it. After just 3 days of just moderate driving, the new coupler busted but this time looked melted. We didn’t get an OEM part and just chocked it up to that one being faulty. Once again, after two days of driving this time, it busted again, this time looking more broken than melted and just like the lip of it, rather than at the bend like it busted both previous times.

We’re at a loss. Called our local VW dealer this time to see if they happen to have the coupler and hose in stock so we can go OEM. They didn’t but when I told the parts guy what was up he suggested to test the coolant pressure and said it could have something to do with the radiator or the water pump. We are hoping to be able to do this this weekend and I will post the results here too. We have VCDS and can rent gauges and such if needed. We would love for this car to at least be reliable enough that we can drive it when we need it!

Something else to mention, though I am not sure if it is related or not: the AC in the car also doesn’t work. It blows fine and everything but is not cold despite being charged properly (I think)

Any ideas or suggestions of what could be going on here or what else we need to check or test?

Is it just the fact that we are using aftermarket parts? I would hate to shell out for the OEM parts and it continue happening and ruin those more expensive parts.

What is the normal pressure range for the cooling system? If it is over pressurized, any suggestions for narrowing down the cause of the issue? I have quite a bit of car experience but not so much with this specific issue.

Posting the VCDS Autoscan and a pic of the first and third fitting that busted (didn't get a pic of the second I guess) below. I know it shows more issues than mentioned above but we just haven’t finished recoding it after doing the MFSW retrofit so that should explain some things here. Other things that show malfunction, I have no clue what is causing those yet but they are not the priority at the moment. lol I will put the Advanced Measuring Blocks for the HVAC system in a comment too in case it is related or anyone can give tips on that situation too.

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Thank y'all so much for any help/hints/suggestions y'all can provide!


2 Posts
Discussion Starter · #2 ·
Group 1:
Compressor Shut-Off Code: 0.0
Engine Speed: 800/min
Vehicle Speed: 0.0km/h
Standing Time: 03:06
Group 2:
Compressor Current (actual): This field is blank
Compressor Current (specified): 0.820 A
Compressor Speed: 1000/min
Compressor Load: 4.8 Nm
Group 3:
Refrigerant Pressure: 10 bar
Radiator Fan Activation (actual): 38.8%
Radiator Fan Activation (spec.): 39.2%
Engine Speed Increase: ON
Group 4:
Outside Temp (unfiltered): 32.0*C
Outside Temp (filtered): 32.0*C
Blank Box
Coolant Temperature: 42.0*C
Group 5: Outlet/Footwell Blower Temperature
Outlet Blower Temperature: 35.0*C
Blank Box
Footwell Blower Temperature: 37.0*C
Group 6:
Evaporator Temperature: 33.0*C
Interior Temperature: 37.0*C
Group 7:
Fan/Blower Status: ON
(no units): 3.0
(no units): 1.0
System Voltage (Terminal 30): 14.00V
Group 8:
Status Terminal 15: ON
blank box
Signal Damping: 0.0%
(no units): 2.0
Group 9: Electrical Heaters
Rear Window Heater (actual): Off
Rear Window Heater (specified): Off
PTC Heater (actual): Off
PTC Heater (specified): 0.0
Group 10:
PTC Heater Driver Intention: Off
Heater Off: Off
Parking Heater Condition: Not Installed
(no units): 0.0
Group 11: Fresh Air Recirculating Air Flap
blank box
Specified Value: 100.0
Group 12: Left Temperature Flap
Current Value: 29.0
Specified Value: 32.0
Cold Stop: 32.0
Warm Stop: 221.0
Group 13+:
Error Not Available

3 Posts
Hello: Unfortunately those couplers are probably aftermarket Chinese. You will be better off with genuine parts. Try Jim Ellis VW in Atlanta, their prices are the lowest you will find anywhere. For example your hoses (1K0-122-157-HP) are $44.00 Plus taxes and shipping. The couplers are $26.00 each. Try to use the spring clamps that came originally with the hoses as they will exert the right amount of pressure and not crack the couplers.
One strategy you can use is to go to your local VW parts dealer and ask the parts manager if he will match Jim Ellis's prices. This has worked for me, don't let them rip you off!
As far the A/C not working, this is probably what happened to me, it was the compressor control valve. If your system is charged but no A/C this is probably the cause. About $60.00 on Amazon or anywhere else. Don't let the experts tell you you need a new compressor before you try replacing this valve. The refrigerant will need to be drained by an air conditioning shop before you can replace the valve (located in the compressor itself)
Hope this helps some. Good luck.

Premium Member
146 Posts
Sorry your TDI is problematic, as well as many of us. So here is my 2cents: the heater hose your car has is a know issue, remember this is the first go at MKV Jetta, BRM etc. So the location of the heater hoses and the turbo charger and the EGR cooler is terrible design. The on the fly fix? That funky silver hose section that was on your OEM heater hose (likely covered in dirt oil soot) is made of heat resistant silicon. By strategic placing this little section, they got that car of the assembly line and out to dealers everywhere. My hose did the same thing and the coupler also failed. I kept the old OEM hose silicon sleeve, bought OEM hose (comes with new silver silicon section) and added the old section to the new OEM hose creating a complete silicon cover for the heater hose, nearest to the turbo. Haven’t had any issue with it since! The black rubber heater hose cannot take the extreme heat from the turbo, the EGR Cooler doesn’t help the high heat in this location.
Jim Ellis has many dealers, VW, AUDI, etc. They are my go to for OEM parts.
as far as your AC goes, This is not a typical US AC system. This compressor runs (when switched on) all the time and uses the computer and an electronic metering valve. This electronic metering valve on the compressor is a common failure… the best part is it’s hard to find, outside of buying a new AC compressor. Yes, mine went out and I elected to replace the compressor (and the dryer).So I am saying if your system is evacuated and charges correctly, you don’t seem sure? To that end, yes you can contaminate the system with plain air. It also won’t work if the refrigerant is over charged (too much) The system must be under a deeep vacuum before charged. A professional ASE HVAC tech would know all the ins and outs to get your system running and the EPA regulations for disposal of contaminated refrigerant.
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