Morris Minor Owners Club

morning all!

another question to add to the long list already. I noticed on a long run in cold weather the other day that the heater is running fine when pottering around town, but when hitting motorways it gets cold. That got me thinking that i could have a stuck open thermostat.

Now i've picked up a new 88degree stat, housing, gasket, studs etc, but when assessing the job i noticed that the heater pipe is bang in the way.

now ive checked that the metal pipe isn't just clipped onto those supports (they're welded), which leaves me with the question of what to do. i imagine undoing the head nuts the supports are attached to is very much frowned upon, but can't see any other option unless someone has a useful trick?[frame][/frame]

i have found if undo the heater take off on the bottom hose it gives you enough room to get to the nuts that hold the stat housing off . but use caution when you do this , so you dont bend the pipe , hope this helps .

What you could do if you don't want to disturb the head nuts is to use an angle grinder with a fine 1mm disc and cut the brackets just below the pipe. Mark and remove the plug leads before you do so and use old towels or similar to collect the dust. Then you can remove the pipe and get at the thermostat. You can then dress the brackets and the pipe and drill two 5 ... 6mm holes in the brackets so you can bolt the pipe back on using P-clips which match the diameter of the pipe. This means you will always have access to the thermostat by simply loosening the P-Clips and turning the pipe for clearance. Nobody will even notice the P-clips if you paint them to match the brackets.

Regards
Declan

No harm in replacing the thermostat but from your description I think the problem you have is due to the rush of air at higher speeds cooling the radiator. The minor is way over cooled due to the size of the radiator.
I find that during the winter months my saloon rarely gets warm and the heater runs cooler. I have a piece of plywood with a letterbox size slot in it that I slip down the front of the radiator, this helps get the engine temperature higher. There used to be leather covers over the grill which served the same purpose.

thanks both!

Declan - might just do that - not sure why that pipe is soldered on, would have thought it was fairly obvious clips would be better there when they were manufacturing it!

trickydicky - i would have thought that, if the thermostat was working, the radiator would have very little impact on cooling at high speed at cold temperatures. I thought that, as long as the engine is below 88degrees, the thermo would stay shut therefore closing off the flow to the radiator and only circulating round the engine/heater?

The same thing happens on my car even with a new stat, even in the summer the engine runs cool. The heater works in the winter but just as you describe, I find it better to have the valve just cracked open to limit the flow so the system doesn't get to cool and the heater stays a bit warmer.

The first thing i would try is to remove the bottom hose from the radiator to remove the coolant. And totally flush out the radiator with a garden hose at both ends. One of mine did the same many years ago and the water was brown.