Catastrophic Heater Failure

[pat911]

I was driving along this morning and all of a sudden huge plumes of what I initially thought was smoke started coming out of the dash vents, around the stereo, the top of the dash, the bottom of the dash, in fact out of every crack and crevice. I initially thought the car was on fire! I calmed down a little once I realised that my feet were being sprayed with HOT water and that it was "only" steam coming out of the dash.

Now, the O rings were replaced by the dealer when I bought the car two years ago as the heater was bypassed and it had to be fixed for roadworthy. I don't know what short cuts, if any were taken in this repair. I've heard of leaks developing in the heater matrix but I've never heard of such a catastrophic failure that caused the entire contents of the cooling system to be dumped into the footwell in seconds. My heater is now bypassed again.

Your thoughts please, Does it sound like I'm up for a new matrix, or could a hose or connection have been blown off due to a short cut being taken in a previous repair? I haven't started pulling the dash apart yet. :censored:

Cheers
Pat.

[FANTOM P38]

Hi Pat,
I thought I had slight leak from oring issue until I got it checked to find that the pipe that leaves matrix where oring is has minor fracture so was weeping oh so slightly under pressure so have had to bypass until I can organise to install new matrix. Quite a job from what I can gather!!:(
So it is quite possible yours was similar but ended up in failure!
Unless you are lucky enough maybe its just hose come off/loose ( wishfull thinking) Pat at British American in Brooklyn is very reasonable with rates maybe worth a call if your not too far. Best of luck. Let us know what you find.
Martin

[p38oncoils]

I was driving along this morning and all of a sudden huge plumes of what I initially thought was smoke started coming out of the dash vents, around the stereo, the top of the dash, the bottom of the dash, in fact out of every crack and crevice. I initially thought the car was on fire! I calmed down a little once I realised that my feet were being sprayed with HOT water and that it was "only" steam coming out of the dash.

Now, the O rings were replaced by the dealer when I bought the car two years ago as the heater was bypassed and it had to be fixed for roadworthy. I don't know what short cuts, if any were taken in this repair. I've heard of leaks developing in the heater matrix but I've never heard of such a catastrophic failure that caused the entire contents of the cooling system to be dumped into the footwell in seconds. My heater is now bypassed again.

Your thoughts please, Does it sound like I'm up for a new matrix, or could a hose or connection have been blown off due to a short cut being taken in a previous repair? I haven't started pulling the dash apart yet. :censored:

Cheers
Pat.

The most likely cause is that the screw that holds the bracket that secures the heater pipes in the heater matrix has fallen out due to treads being stripped or not adequately tightened in the first place when the "O" rings were replaced.

[pat911]

The most likely cause is that the screw that holds the bracket that secures the heater pipes in the heater matrix has fallen out due to treads being stripped or not adequately tightened in the first place when the "O" rings were replaced.

That's what I'm hoping for.

[Hoges]

If it is the heater core, a number of P38 owners o/seas have used the heater core from an Audi A6. Cheaper and more effective. Do a search on RANGEROVERS.NET HOME (http://www.rangerovers.net) . It appparently does away with the need for o-rings. There is a bit of fiddling however as the pipe diameters are different from those in the P38 but this can be apparently fixed with a couple of adaptors...

[PaulP38a]

I just purchased a couple of these Audi A6 heater cores (new) from an car parts store in the USA for less than $50 delivered to my US shipping address. By the time these are forwarded to me in Oz it might be around $100 all up which I am pretty happy with.
I don't have any problems with my HC at the moment (knock on wood) and this is a good test of the forwarding service.

[Green Rover]

The most likely cause is that the screw that holds the bracket that secures the heater pipes in the heater matrix has fallen out due to treads being stripped or not adequately tightened in the first place when the "O" rings were replaced.

This happened to mine, and you just use a bigger screw in the existing hole. And use a screw with a better head too. :)

[zedcars]

From my experiences the heater carcass where the retaining screw passes through to hold the heater pipes has stressed and pulled through; allowing a massive loss of coolant top occur.

I have used a fatter headed screw as Green rover has mentioned but these days I raid my diesel fuel injection parts bins for a Bosch diesel injector pump delivery valve holder clamp. These are two half moon blocks of steel that look like key ways and are clamped between each delivery valve on the in line pump types.

If you take one and do a bit of sculpting with a file like Michael Angelo you will find it will fit perfectly into the recessed space where the original screw was clamped down onto plastic carcass. Take a new allen screw which is sufficiently longer and American fractional to engage with the pipe clamp and pull it all together. Lubricate the new O ring with A/F before you install them.
I have done about 5 last year so far with no come backs.
Dennis
zedcars

[pat911]

Thanks to all those that have replied.

I still haven't looked at the problem as it is warm in Melbourne at the moment but I will have to look at it soon. I'll let you all know what the problem is when I investigate it, but from the replies given it is looking like the retaining screw has given way.

Cheers
Pat

[pat911]

Ok, finally got around to fixing this problemn today. I ordered an new heater matrix from the UK for $105.00 delivered.
what a job to get it out. There are no shortcuts, the steering column is in the way and either that or the heater box itself must come out of the vehicle, after the dash has been removed of course! I chose to remove the heater box as I didn't want to mess with the steering. Anyhow, all done now and I have a nice warm P38 with defrosted windows again.

The old matrix did fail catastrophically. The plastic housing cracked open. I've got a photo of the old matrix below. As you can see, the plastic cracked and blew open where it is clamped onto the radiator cores. You can see right through the crack and out one of the pipe connection holes. No wonder the cooland exited at such a high rate of flow.

Regards
Pat.

[Rangey89]

I had the heater matrix fail on mine in the same catastrophic way, just glad I had my work boots on!

As for doing the job, I followed most of the detailed job from the Rangerovers.net website, except I didn't remove the dash top. I stripped out the drivers side under dash area and cut through the steel frame on the dash to get it to clear the matrix and out it came. Easy as!

Just riveted the frame back together when I reassembled it.

Been a month now, no leaks! Fingers crossed.