Info needed: Morris C8 radiator

[pauldavies]

Mike more than frustrating but sort of get used to it, been in touch with a couple of sources but nothing yet. Maybe try one of the spring makers if I get blanked out as there are a few of them that do individual springs, I was going to take the C8 up to Bundy for our MJCQ club weekend next week but the Austin champ will do nicely.
Regards and will let you know of any success.
Paul

[Richard Farrant]

Hi Paul,
I have found some info regarding the Air-Lock filler as fitted to your Morris, and Bedford QL. It is not a pressurised radiator. There is no overflow tube as in some radiators. To quote:
"To prevent dilution of antifreeze caused by careless topping up, an 'Air-Lock' type radiator filler is fitted. This filler incorporates a spring loaded valve in the filler tube which permits steam to escape through relief holes in the cap, no overflow pipe being used. The filler cap must screwed right home to open the air lock valve in the filler."

I had similar problems a few years back on the QL and was not filling the rad more than in the past, but I did find the thermostat was stuck open and wondered if it had been playing up and sticking shut as well. Water would blow out and coolant temp was normal, it would then stop blowing out and run normal until it would happen again for no reason. I changed the thermostat and stripped and cleaned the Air-Lock, did find the adjusted ring depth was not correct, so reset it. Watch that you are not overfilling the rad.

regards, Richard

[Mike K]

I agree with Richard and we should have thought about the thermostat ages ago.

My C8 ( the little CMP 4X2 ) would blow coolant out the radiator cap with some force , usually after climbing a hill. At the time, I was running it without a thermostat .

The thermostat does a important job , but it has a second function, it restricts the coolant flow into the top tank , without this restriction, the coolant fills up the top tank and eventually pressure builds up and it blows out.

I would check your thermostat . Is it the correct type ?

My CS8 4X2 has a different cooling system . They fitted your type to the 4X4's .

[pauldavies]

Guys there lies the conundrum "no thermostat", don't use them here in QLD but maybe I will need to find one! I purchased some bronze today and will make a new filler tube and castelation ring on Wednesday, I am borrowing a friends lathe to do the job. The spring I am sending to a company in Brisbane to make a stainless replacement as no-one does bronze springs anymore, I haven't overfilled with coolant as from your early advise Richard I just touched the core and at least 4 litres of coolant blows out so it is excessive and that is with stopping straight away. It is interesting that it blows as the temp gets to running temperature so the thermo theory could be correct. Any idea on spring tension?
Regards
Paul

[Mike K]

Originally Posted by pauldavies

I purchased some bronze today and will make a new filler tube and castelation ring on Wednesday,
Paul

OK sounds good . Bronze isn't cheap . You could try making a new filler tube from aluminium as a 'test run', doing this will also check your set up in the lathe. Then if the alu one fits OK , go for it with the bronze . I'm always nervous when machining a piece of expensive metal , one slip up and its junk

[Richard Farrant]

Originally Posted by pauldavies

Guys there lies the conundrum "no thermostat", don't use them here in QLD but maybe I will need to find one! I purchased some bronze today and will make a new filler tube and castelation ring on Wednesday, I am borrowing a friends lathe to do the job. The spring I am sending to a company in Brisbane to make a stainless replacement as no-one does bronze springs anymore, I haven't overfilled with coolant as from your early advise Richard I just touched the core and at least 4 litres of coolant blows out so it is excessive and that is with stopping straight away. It is interesting that it blows as the temp gets to running temperature so the thermo theory could be correct. Any idea on spring tension?
Regards
Paul

Hi Paul,
The brass ring should have a rubber sealing ring bonded to the lower side, is this missing on yours? Remember this does not seal the radiator cap, it only seals off the air gap above coolant in the header tank when you remove the cap to check the level, so you do not overfill.
Another thing that gets overlooked is the fan belt, is it gripping and adjusted correctly. Some British vehicles used belts of a different V angle to the standard A, B and C varieties. You may have to compromise, but worth checking as belt may be slipping at times.

[guy labbe]

I am a bit puzzled by this discussion. I have two Morris C4 for the moment and didn't find a thermostat in any of these two engines and even don't can find a notification about a thermostat in the workshop manual.

On my C4 the airlock valve was missing but luckily I did found a complete set up in Norway.

[guy labbe]

on the left side of the picture you can see the air lock set up.

[Mike K]

Originally Posted by guy labbe

I am a bit puzzled by this discussion. I have two Morris C4 for the moment and didn't find a thermostat in any of these two engines and even don't can find a notification about a thermostat in the workshop manual.

On my C4 the airlock valve was missing but luckily I did found a complete set up in Norway.

Even If a thermostat is not an original item in the 4 cyl. engines , it is worth Paul trying a thermostat as an experiment because it might be the answer to his issue. Are there any more of those NOS parts from Norway available ? It has been ages since I last heard from Rolf.

Without a thermostat in the C4 , there must have been some kind of restriction in the coolant outlet from the engine, limiting the coolant flow to the header tank . The thermo syphon system requires that there is a significant temperature difference between the engine and the radiator , this difference aids the coolant flow . If the engine and the radiator are at the same temperature ie no thermostat fitted , then that is not ideal and can lead to problems