Heater Control Valve - suspected leaking -2004 V6 2.5 S TYPE

[MCALLISTERABERDOUR]

Hi,
Had a mysterious water leak in my car since April and think I have finally traced it to what I believe is the heater control valve. Sitting behind the radiator below the expansion tank it looks very corroded and damp with sometimes a trace of water to be seen on the cross member below it. Underside of it felt damp.
Is this a common fault and would it be a big job to replace ?

Thanks

[Montana5]

More likely to be the expansion tank, very common fault.

Doug.

[MCALLISTERABERDOUR]

Hi Doug,
Had this issue since April and cars been checked out by my own local garage and again by some of our regional members recommended Jag specialist to no avail. Main worry at that time was cylinder head gasket failure but again all appears okay. Only thing they found was the pressure cap was leaking slightly. Water temperature is normal and I fill it up every time the low coolant level warning comes up.
That was one of my first thoughts but seemingly all is okay there. Only reason I think it's the valve is that it is extremely corroded to look at, looking and feeling damp with the trace of water lying immediately below it. It's gradually got worse and is more evident when I am pulling the caravan. A trip up to Blair Atholl this week of just under 70 miles with the caravan used about 1 litre of water whereas in May the same trip would have been a lot less.

Cheers
John

[oldtimer]

Hi again,
So you may have found that illusive leak then!

I have just been browsing through the S Type cooling section cos I'm sure I've read and seen photo's of the valve with pipes hanging off like tentacles. I mentioned ages ago about a dedicated area for how to fix but it never materialised, however there was a comment with a list of things that could be included. Interestingly, there was reference to changing a 3/4 way valve so the topic is secreted away somewhere. The very point I was trying to make!

As regard your enquiry as to the degree of difficulty. I have never done the job and looking at it's location not one that I want. The hose connections are not familiar to me and cannot see how to separate them. Like many jobs, dead easy when you have done it once.

Do you know how to do a search on this system - I don't - that might reveal something

An eventual progress report would be helpful.

Oldtimer

PS You are convinced that the leak is from that valve !!??**??

[jeff1954]

Hi John
Iv'e changed the valve on mine, It's quite easy to do providing you have some means of getting under the front of the car (I have a pitt) There is a pannel that goes from one side to the other that has to be removed. Then it's just a case of draining the rad and off you go,I used oppertunity fill with new antifreeze.

Jeff

[MCALLISTERABERDOUR]

Hi Oldtimer,
I am pretty well convinced that's where the leak may well be and I am going to monitor it very closely for a couple of weeks before I put it into my local garage for repair. My guess is that water is being forced out under pressure as vapour from this area when the engine is running, don't know what effect running the heater will be now that the temperature has changed. There is no trace of anything on the floor when parked up at any time. The guy's in the garage are pretty reasonable there and I have used them for years with no problems to date.
Caravanning finished for this season anyway so engine should be less stressed and cars due an MOT then anyway so might as well kill two birds with the one stone.

Hoped that might be the case Jeff that you could get away with stripping out some of the panels underneath to get to it rather than have to have the radiator and all the gubbings out. Still looks very tight and fussy to get into. Obviously as you have done I would be getting the system filled again with the correct anti freeze content for winter protection.
I will keep you posted as to my progress.

John

[J44EAG]

I`ve had an ongoing coolant leak on my V8 for some time.

The header tank is not dripping and I could find no other leaks on the top side of the engine. On the ramp the other day revealed signs of coolant leakage around the edges of the sump. Some stripping out would be required to dind the source. Water pump, thermostat areas were also checked.

Annoyingly or perhaps fortuitously, the electric fan would cut in if coolant level became low as a first indication a top up was needed. J44 is of the age now where I`m reluctant to spend money on an aging car, so really I`m just trying to hold the thing together without spending more than I have to.

My local motor factors suggested putting a small can of K-seal in the coolant system. I`m told this is what the AA repair guys use and find most effective. The instructions claim minor leaks will stop in minutes. Whilst reluctant to place chemicals in the engine which might possibly block up parts in the future, I poured the K-seal into the header tank and topped up with neat antifreeze. That was three weeks ago.

Since then I have covered well over 800 miles and the header tank level has remained unchanged.

Magic bodge fixes in a bottle are not to be regarded as manufacturer approved, so the use of K-seal my choice and potential risk in the future. All I can say is that K-seal is working for me, has stopped the leak and I`m no longer concerned on long journeys that I should pull over every couple of hours to check the coolant level. My regime is now a quick under bonnet check before I set off on a journey. No change in tank level is enough reassurance for me to begin to travel.

K-seal did what it said on the bottle. Decide for yourself perhaps if the product might be useful to you.

I`ve told this story before on this site. Years ago my Father had a Rover 820, bought new and always dealer serviced. A few years into service, the heater matrix began to leak causing a curry like pong inside the car. After a while the pong rose at an exponential rate and all who drove the car began to despise it especially in the winter when the windows would constantly steam up and the driver acquiring an odd smell himself in the process.

The car was old and we just used the heap as a family hack. Eventually something had to be done to fix the problem. To replace the matrix meant a cabin strip out and we just couldn`t find the interest to do the job. Father, as a desperate measure put two egg whites in the header tank as a final attempt to keep the car going a bit longer. Five years later, that old Rover was still on the road, had stopped making curry and finally going to the crusher as part of that £2000 trade in scheme to get wrecks off the road and encourage new car sales.

Mike

[MCALLISTERABERDOUR]

Hi Mike,
Sounds a good product. Unfortunately we tried Radweld previously and I don't think I can put more in for exactly the reasons you say.

Thanks

John