Cable Operated Heater Valve won't stay shut

[svenedin]

I fitted the new valve just now. It's a simple job with a ratcheting ring spanner with the rocker cover off. A pain to do without such a tool. The offset valve has a special gasket that has a correct way up due to the offset.

I also fitted a heater return pipe I had cleaned up and repainted and a Winter thermostat, 88 degree C as well as stainless steel thermostat housing studs, washers and flanged nuts and a more modern gasket to replace the cork one. The thermostat housing is a better quality modern one that is supplied with slightly oversize stud holes so there is no need to drill it out larger to prevent it seizing on the studs.


The engine was professionally rebuilt over the winter of 2024/2025 so I was rather surprised to find a 74 degree C thermostat in there......I did wonder why the engine took ages to fully warm up and the heater was poor. I think 74 C might have been standard at one time in Minis but 82 C in Minors. Not sure about that but 82 C is usual these days.

I noticed that even after just 7 months, the thermostat housing studs were corroding. The stainless steel ones (Minispares) should be less of an issue but of course I liberally greased them with silicone grease.

All seems good with a run up to temperature but the weather is too dreadful for a run out today.

Stephen

IMG_2699.jpeg (3.08 MiB) Viewed 1590 times

[svenedin]

Test drive success. Nice hot heater very quickly with 88 C thermostat. Heater shuts off and stays off. Engine heats up much faster.

Here's a galvanised heater stud (replaced with stainless steel) showing early signs of corrosion after just 7 months in service.

Stephen

IMG_2701.jpeg (995.34 KiB) Viewed 1556 times

[svenedin]

Of course it couldn't all go well...........noticed drops of oil on the drive. Timing chain cover yet again. The bane of my ownership of this car for 36 years. Basically it has never stopped leaking oil from there. I sort it, it stops for a few weeks and back we go again to leaking.

It leaked for years with a tired old engine. It leaks with a rebuilt engine, a different engine front plate and a perfect timing chain cover. Every time it starts to leak again I find the bolts are no longer tight. They're not exactly loose but they're no longer nipped up either. I think I am going to have to put some thread lock on the threads to try to stop this never ending annoyance. I should have done that last time when I had the whole front panel off and the coolant hose out of the way so as to access all of the bolts. Some of the top ones are very awkward to re-fit even with the radiator and bottom hose out.

Stephen

[Bill_qaz]

It maybe gasket compression rather than the bolts backing off.
Have you tried re-torque when hot?

[svenedin]

I’ve tried that in the past but it’s only possible to do the bottom bolts if the engine is hot. The bottom radiator hose blocks access to several bolts and it’s easy to get burned by a hot engine.

It's not a really big deal but it's a bore. For years I have kept a big metal tray under the car to catch drips but I have upset people over the years by dripping oil on their pristine drives.

Stephen

[svenedin]

Longer test drive and all is good. Nipping up the timing chain cover bolts has completely stopped the oil drips but then again it always does until next time.......

Heater is very toasty. So much so that I had to party shut it off. I'm pleased to say that the heater valve will stay open, shut or anywhere in between so it is possible to regulate the heater temperature as had always been the case until the faulty valve.

This is the advantage of the cable operated valve. Not only can you operate it on the move (unlike the tap type valve) but it can be adjusted and there is regulation of the temperature from within the cabin.

There really is a huge difference in the heat output of the heater between the 74 and the 88 C thermostat.

Stephen