L322 heater problem

Hi guys,
I'm at the end of my tether with this one!

The heater has started acting up big time and I can't find any other posts with the same symptoms, the heater goes cold, then both sides balance out luke warm at absolute best, then one say the passenger side goes freezing cold and the drivers side gets hot, then the drivers side will go freezing cold and the passenger side will get hot, then they'll both go cold, then it could be anyone's guess! Been trying all sorts over the past few days but to no avail.

Doesn't seem to be any air in the system it's returning to the bottle with no air bubbles, changeover valve wasn't stuck when stripped down, feed pipe to the matrix has lots of flow and pressure, return from the matrix seems to be pretty slow? I've had all the pipes off to the matrix and washed through with the hose pipe and there's no restrictions unless I try the hose pipe down the return from the matrix, is there a one way valve somewhere?

Heater seems to work better on the fbh so water has to be getting through?

Fbh has now started to run constantly since the heaters have been acting up so I pulled the fuse to it and the above selection of events is what I get.

Any ideas before it goes in the bin?

Cheers!

Hi

this is the only thing I can find ref the heater core

Heater Core
The heater core is internally divided into two separate halves, with separate coolant inlets for each half and a common coolant outlet. On the manual system, the two coolant inlets are connected to a common feed from the single coolant valve. Each coolant inlet pipe is connected to a feed from a separate coolant valve.

I feel for you fella, I'm having similar problems front passenger side warm, drivers side cold after car is up to temp but warm whilst warming (if that makes sense). Rear heating also cold.
You seem to have done more diagnostics than me so far as I'm still searching for a warm covered area to work in at present.
Good luck with your fix, I'll let you know if I find a cure for mine in case it helps you too.
(MY 2010/11 4.4TD V8 Diesel AB)

Oh, also meant to mention, someone on another forum said there was a way to reset the HVAC system on these cars and that someone had posted it on a forum somewhere, still not found it yet...worth a try though.

Thanks for the replies, I'm going to buy a pressure tester to see if there's any pinholes anywhere I can't spot that is dragging air in

abs66 said:

I feel for you fella, I'm having similar problems front passenger side warm, drivers side cold after car is up to temp but warm whilst warming (if that makes sense). Rear heating also cold.
You seem to have done more diagnostics than me so far as I'm still searching for a warm covered area to work in at present.
Good luck with your fix, I'll let you know if I find a cure for mine in case it helps you too.
(MY 2010/11 4.4TD V8 Diesel AB)

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Strange thing is the rear is red hot, don't seem to be having any issues there just the front!

abs66 said:

Oh, also meant to mention, someone on another forum said there was a way to reset the HVAC system on these cars and that someone had posted it on a forum somewhere, still not found it yet...worth a try though.

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I've got a lynx evo and I've reset everything and there's no faults there now except for the fbh because I keep pulling the fuse so that I can see what the heater is doing when using engine coolant only.

I might see if I can test the hvac components individually with lynx and see if that comes up with anything
Hopefully find a cure soon!

Bit of an update

Had another good few hours at it today, pressure tested the system and it remains constant so no leaks, decided to try and bleed it for about the hundredth time, if I run the engine with the bleed screw removed completely the water returns at a normal rate and then all of a sudden starts flooding out and I get heat from the vents, then it steadies out again and the vents go luke warm after 30 seconds or so it drinks some water, then the whole process starts again? Strange.

The 3 pipes running to the twin heater valves were previously either stone cold or just luke warm, I've had them scolding today and actually burnt my hand but they kept going luke warm then scolding again which is weird also.

Anyway I read the fault codes and on numerous occasions I get "auxhilliary water pump short to ground" cleared codes and after 3 attempts it went away and hasn't since come back, not sure if this pump is needed for the heating in the car or if it's just for when the fbh is running when the car is off?

Coolant temp is running anywhere between 70 and 80 degrees stood at idle, Not sure if that's right or not.

The Aux pump is there for when the flow through the heater matrix is too low - this can be when the engine is idling also not just for the FBH.

There should be one hose to the Heater Valves/Aux Pump and then 2 hoses leading to the bulkhead connections to the Heater Matrix. if the valves are fluctuating on and off, you will get a rise and fall in the temp from the hoses to the heater matrix.

The thrid hose from the heater matrix is the flow return hose back to the engine bay.

Thanks for the reply,

Right okay, yeah I've taken the plenum out to attempt to figure out where everything goes, so if the heater valve is playing games then that would cause the issue? Is there any reason why they would be opening and closing when they please?

They will open and close to maintain the correct temp in the matrix to maintain desired interior cabin temp.

Saint.V8 said:

They will open and close to maintain the correct temp in the matrix to maintain desired interior cabin temp.

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Or not ....apparently.

Saint.V8 said:

They will open and close to maintain the correct temp in the matrix to maintain desired interior cabin temp.

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So could it be a sensor problem Ant?

Much appreciated for all the replies, I have finally found the cure to the range rovers cold! I'm going to look like a bit of a wally here because it was the first thing I went to!

It's the changeover valve, the rubbers are swelled that badly it's blocked all ways! I removed it again today to have a closer look and strip down.

I Got some spare hoses and created a bypass to remove the valve and within minutes (and a big water top up) the heaters went red hot, temp gauge was just out of the blue.

Can get one from land rover on Saturday at the very unreasonable cost of £269.
I don't really want to risk buying a seal kit and figure out the solenoid doesn't work anyway.

This has been an expensive week as the alternator internally combusted on Sunday so hopefully no more problems for a while!

Danastle1992 said:

Much appreciated for all the replies, I have finally found the cure to the range rovers cold! I'm going to look like a bit of a wally here because it was the first thing I went to!

It's the changeover valve, the rubbers are swelled that badly it's blocked all ways! I removed it again today to have a closer look and strip down.

I Got some spare hoses and created a bypass to remove the valve and within minutes (and a big water top up) the heaters went red hot, temp gauge was just out of the blue.

Can get one from land rover on Saturday at the very unreasonable cost of £269.
I don't really want to risk buying a seal kit and figure out the solenoid doesn't work anyway.

This has been an expensive week as the alternator internally combusted on Sunday so hopefully no more problems for a while!

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Optimist, it's a Range Rover, they don't do reliable.

Datatek said:

Optimist, it's a Range Rover, they don't do reliable.

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I know Haha, it's about ready for a torque converter as it's starting to judder on a slight incline below 30 ish, was serviced last year and made a massive improvement, basically fixed it for almost 12,000 miles, but it's just clocked over 200,000 miles now so how far do you go

Got my replacement valves off the bay of E, been working fine 12 months.

kds said:

Got my replacement valves off the bay of E, been working fine 12 months.

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Second hand? I can't find a new one with the same part number, I've found one for an l405 but it says it's not for my car even though they look identical just a different part number

Danastle1992 said:

Second hand? I can't find a new one with the same part number, I've found one for an l405 but it says it's not for my car even though they look identical just a different part number

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No brand new, must have been right at the end of 2017 (longer ago than I thought) because its gone off my purchase history now, dont remember but must have just put the part number in to find them.

@Danastle1992 does ebay item 332356783074 fit the bill ?

kds said:

@Danastle1992 does ebay item 332356783074 fit the bill ?

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Ahh no this isn't the valve that I need, it's this one 283440379141
Well, it looks identical to mine but has a different part number, maybe it's an updated version?

Anyway I stripped mine down again and tested it on a battery and the solenoid activates so I've ordered a repair kit for it to replace the plunger, diaphragm and seals as 2 swollen rubber seals is what's preventing water flow no matter where the plunger is.

£22 for the kit so better than £269 from land rover!