Info needed: Morris C8 radiator

[pauldavies]

Had a drive of my Morris C8 today and it blew out a hell of lot of coolant about twenty minutes into the drive, the sealant to seal the thread may not be the required temp spec so I would ask of you all is there a high temp sealant that will do the job?
Paul

[Mike Kelly]

Paul

Can you explain the issue in more detail ? Where is the "thread" you mentioned ? Is it the drain tap thread ?

[pauldavies]

Mike the threaded ring has to be 9/16 from the top and sealed with I hope silicon sealer, I have been having problems with this leakage since day one and Richard Farrant has been helping me along with it. I will try some plumbers thread sealant today as that can stand fairly high temp.
Paul

[Mike Kelly]

Paul

I have around 6-7 Morris CS8 and PU radiators and I not seen that type of cap on any of them My caps are a simple brass cap with a internal thread , thats it , no spring .

[pauldavies]

Thanks Mike and I have installed the cap assembly with some loctite high temp sealant and have left it for a couple of days to go off and will fire it up this morning, very hopeful it will do the job. In your radiators what releases the pressure?

[Richard Farrant]

Hi Paul,
This Air-Lock valve in the filler was also used on some Bedfords, like my QL. After owning it for about 30 years now it has never given any real trouble then about 3 years ago it started blowing water out of the cap intermittently and I removed the complete valve and checked it over. The spring had rust on it and was stopping full pressure of it onto the sleeve and sealing ring. I also found the screwed ring was not set correctly. Once I sorted this all out, and filled to the correct level (a bit lower than before) the blowing out stopped. Temp gauge only showed normal temp when water blew out, so doubt it was overheating.
Hope this is of some help.

regards, Richard

[Mike Kelly]

Originally Posted by pauldavies

. In your radiators what releases the pressure?

As far as I know there is no pressure, its a thermo syphon system with the water pump as a backup The radiators on these trucks are large and wide . Maybe Richard F can provide more info ? Thanks Richard over to you

[pauldavies]

It's been a while since I updated on my overheating problems with the C8, I am just back from 6 weeks in Canada so here goes.
Original problem being the coolant being pushed out of the radiator so after lots of investigation/repair and finally having the radiator stripped and cleaned, today I checked for combustion gas in the coolant and whilst doing this with the cap off I watched the coolant rising and pushing out of the radiator filler, once it was finished rising the level settled down just below the filler tube. The engine was running while this was going on so I carried on with the combustion gas check of which all was clear, I replaced the radiator cap and had a run up and down the garden with no ill effects. I will take the truck for a run out on the road tomorrow and hopefully all will be well.
Paul

[Wayne Hingley]

Paul, (not knowing what you have checked already) is there an overflow/vent line on your radiator? If so, could it be plugged or kinked, and thus not "breathing" as things expand and contract?

Good luck with your road test!

[pauldavies]

Hi Wayne and I am unaware of any overflow/vent pipe, it being an air lock system which is something I have never come across till getting the C8. I have tried just about everything to get the truck to run without the coolant overflowing after twenty minutes driving and the only thing left would be to strip the water pump to see if the drive turbo is intact, I also don't have a thermostat fitted which would I suppose make a bit more pressure in the system but in Queensland the need for a thermostat isn't there. Let you know how I go with the road run.
Paul

[Lynn Eades]

Paul, a thermostat is employed to maintain a MINIMUM operating temperature. The engine components are sized to run in a given temperature range. Anything less and the wear rate goes up, while the performance suffers. Keeping the temp down is the job of the radiator.

[pauldavies]

Lynne l have pleasure in informing every one that my radiator problems are over, the stripping/cleaning of my radiator worked. As I said in yesterdays post the fact I was testing for exhaust gases in the coolant and the coolant level equalised itself while I had the radiator cap off seems to have done the trick, had a fuel starvation problem in the run today but I will address that tomorrow. I don't have a full thermostat in my Austin Champ but the partial thermostat keeps up the pressure in the system so I thought maybe that would make a difference but in the case of the C8 no, worth a thought. Thanks every one for their input.
Paul