Rear heater hoses

[rover1066]

The 2 very short curved lengths of hose that run between the main long lengths of hosing to the rear heater under the rear seat need replacing urgently!

Can anyone tell me their diameter, as I'd like to source the hose before pulling the old ones off! Am I right in thinking they are just bent into their curve as opposed special hoses?

Many thanks, Mike

[Phil Nottingham]

Special hoses curved I am afraid - 1/2 bore - I made up right angled bends with capillary copper water pipe bends and used two short lengths of standard 1/2 heater hose till I picked up some suitable moulded tyoes

[rover1066]

Phil, thanks once again for your help. I rang Wadhams who stock these small curved hoses so looks like all is well. Off for its MOT in the morning so fingers crossed!

[stantondavies]

Investigating a pool of liquid near the o/s rear door I find that water is dripping from the elbow into the heater. Eyesight problems mean that I find it difficult to see exactly what is going on unless I can get my head in the right position - VERY difficult at times and certainly so in this case.
In my naivety I thought closing the tap on the heater box would stop it, but of course, that stops the circulation only and doesn't isolate the pipework. I have clamped the return pipe by the engine and water loss has stopped.
I bought a replacement set of hoses sometime ago in anticipation of the original hoses going at some stage, but hadn't got round to replacing. What I did not appreciate, and what JRW didn't tell me is that there are some special elbow hoses onto the rear heater connections! Haven't decided how best to replace those yet.
Searching yielded some useful information which I will try to reproduce in a separate post.

[stantondavies]

Here is a distillation of wisdom previously posted with due acknowledgement to the original authors. I hope this may prove useful to others.


Rear heater Pipes
Thread Started on 30 Mar, 2005
Has anybody changed the rear heater pipes to copper, leaving rubber hose connects at both ends to stop stress through vibration. My only concern is that Anti freeze/rust inhibitor will react with the copper? Thanks Karl
Reply #1 on 30 Mar, 2005
Its a good idea to replace the heater pipes as these are often overlooked and they can result in unnoticed total coolant loss in less than a minute! I have never heard of completely replacing with copper although I have used 1/2 pipe and fittings in parts and others have replaced the corroded alloy pieces under the bonnet with copper items.
I cannot see how there will be any problems with coolant as the radiator has copper and brass components.
I did once think of using the modern plastic plumbing pipe as this will take the pressure and is suitable for hot water.
In the end I used standard 1/2-inch heater hose protected by convoluted tubing used for electrical work.
Reply #2 on 31 Mar, 2005
Ditto, just don't forget to check those rear heater pipes as often as you check the engine bay rubber pipes.
As Phil says, they can leave you stranded and waterless if they are neglected.

Rear heater hoses
Thread Started on 17 Apr, 2006
The 2 very short curved lengths of hose that run between the main long lengths of hosing to the rear heater under the rear seat need replacing urgently! Can anyone tell me their diameter, as I'd like to source the hose before pulling the old ones off! Am I right in thinking they are just bent into their curve as opposed special hoses? Many thanks, Mike
Reply #1 on 17 Apr, 2006, 18:10
Special hoses curved I am afraid - 1/2 bore - I made up right angled bends with capillary copper water pipe bends and used two short lengths of standard 1/2 heater hose till I picked up some suitable moulded types. Phil – Nottingham
Reply #2 on 18 Apr, 2006, 9:29
Phil, thanks once again for your help. I rang Wadhams who stock these small curved hoses so looks like all is well.

Rear heater valve
Author: Richard 6/14/2004
Fixed to the o/s, outside of the heater is a two-port valve which controls the flow and return to the rear heater. The steel ball bearing in the plunger will invariably seize meaning that the valve is either on or off, and there's not much one can do about it.
Author: Dan 6/14/2004
Has yours seized up then? Since I unseized mine (with some brute force admittedly) it leaks all over the place. I'm just gonna make up some 10mm copper pipework to replace it completely in an always on type situation. Is it possible to recon old units?
Author: Jon Cooper 6/14/2004
Hello, I tried to repair my old one but dismantling was pretty destructive. Opening the top is fairly easy but getting the rest apart defeated me. I think there is a metal can pressed into an alloy casing and the two corrode together for 30 plus years. I got a very decent replacement from David Green which has worked perfectly.
Author: Adrian 6/15/2004
Seems that the problem with these valves is seizure through lack of use. Since I replaced mine, I often operate it (close and open it) whenever the bonnet is open - hopefully it won't seize again.
Author: Davie-Edinburgh 6/15/2004
Does the heat go to the rear seats if the knob Is up or down?

Rear heater tap
Author: Dan 2/14/2004
Having just overhauled the cooling system on my p5b - including freeing up the rear heater tap - I've noticed that it now has a weep at the top where the knob is attached. Is there any way to service or repair these items, only I couldn't see any way to get it apart.
Author: Tom – Clydebank 2/14/2004
I have never had one apart but I am pretty certain that it will use "O" rings on the central spindle and these should be replaceable. If it was originally assembled, it must be able to come apart. Tom.
Author: Phil Jones - Notts 2/14/2004
If some **** assembled the valve the another one can dismantle it. Is it that bad? Mine leaked for while after unseizing but it stopped eventually and still is OK 10 years later.
The Mk 111 used a Tap assembly which was a quality product ie you turned it on or off rather than pressed it down I suppose these are more long lasting and serviceable
Author: Jon Cooper 2/14/2004
Hello, you can get the top off the valve but the inside is divided in two compartments. I think it consists of a steel can pressed inside an alloy casing and separating them, after 30+ years of rusting together, looked near impossible.
Author: Tom – Clydebank 2/15/2004
It is basically a shuttle valve, similar types are used in pneumatic circuits. Usually one or both ends come off and generally the ends are retained in place by socket head screws, sometimes these are also utilised to fix a mounting bracket. It is also possible the end or ends may be screwed into the main body, but I would think that unlikely unless there were flats on them to fit a spanner for removal. With an end removed, the spindle or shuttle should just slide out. Tom.
Author: Dan 2/16/2004
I put it in a bath of diesel for a week. Then I put it in a vice and gave the bottom seal a couple of good whacks with a punch. Sure enough it freed up.
Author: Tom - Clydebank 2/16/2004
I found that mine was blocked with sand. When the rubber hoses were removed from the aluminium pipes they were found to be solid and plugs of sand came out with the aid of a drill used by hand. Remove the plastic handle if you have to tap it as it will break easily as it is probably made from phenolic resin. Tom

Leaking rear heater
Author: Dennis Lines 1/19/2004
My rear heater valve under the bonnet has been bypassed by a copper connecting pipe. I refitted the hoses to allow water flow to rear heater, opened the valve, and water poured on the ground from beneath the position where rear heater is mounted. Is this likely to be a faulty hose connection or is there likely to be a leaking heater radiator? If the latter, is the heater easy to remove?
My heater has always been very poor. Would bypassing this valve have rendered a poor heating supply to the front vents? My P5B Coupe has been standing for some time, but engine runs well and radiator water and antifreeze is clean.
Author: Tom - Clydebank 1/19/2004
Dennis, it is more than likely that the hoses are burst (probably by the jubilee hose clips at the heater itself, and I would check this out first. The heater itself is also quite easy to remove for repair if you lift out the rear seat. The heater is held to the floor by two small bolts.
The front heater is probably poor as the flaps seize up and as was mentioned last week the front flap often remains open despite the control lever showing closed. Check the front offside of the heater and get someone to operate the control in the car, and you will find that the control lever moves away from the flap lever but the flap spindle does not rotate and follow. If you have the manual go to section "W" p3 screen control levers, check that "D" moves up when "B" moves away.If it doesn't get some jungle juice on it and a pair of pliers until it is free. (For jungle juice read Plus gas, WD40, Lusol, or diesel), and finish off with some oil for lubrication. Tom.

Rear Heater
Author: Phil Jones - Notts 12/21/2003
A question for Mk3 owners onwards. Do the louvre vents on the outlets under the rear seats point downwards to the floor or upwards into the car?
Author: Tom - Clydebank 12/23/2003
Phil, they should point down, to direct the air to the floor and forward. It would be most uncomfortable for a rear seat passenger to have hot air blowing on his or her legs all the time. Tom.
Author: Phil Jones - Notts 1/3/2004
The hoses could have partially collapsed and you should check them - the valve only closes one side of the rear heater circuit so in the event of a hose bursting the full 15lb pressure empties the radiator in a couple of minutes if the engine is running. If you look under bonnets of some P5B you will notice they have been bypassed.
I had this happen to me a few years ago and I only noticed because it was at night in traffic and steam and spray was going over all the cars next to me as the hose actually broke in two as was waving around under the car!
The hoses being the original and then 27 years old had become very brittle at the ends and had partially flattened in places inside the insulation. Replacing these caused 2 other heater hoses to fail on two separate occasions so if you change one its best to do the lot. It saves wasting anti-freeze.

[Warwick (Ozcoupe)]

Copper is definitely okay as a replacement for coolant tubing. It is preferable to aluminium which will eventually corrode between the rubber hoses and the outer tube walls where it gets wet but doesn't get a flow of inhibitor.

I replaced the heater tubing and the steel tube that runs under the inlet manifold from the water pump to the back of the engine on my '76 Range Rover in about 1987. The vehicle sat idle (neglected?) in a shed from 1989 until 2 years ago when a friend bought it for use on club events and it is still as good as new.