1936 Ten Saloon Cooling system

Mike M
Posts: 11
Joined: Thu Nov 24, 2011 6:21 pm

1936 Ten Saloon Cooling system

Post by Mike M » Thu Nov 24, 2011 6:41 pm

Gentlemen,

Having fired up the car after a lengthy lay up, it seems that the water pump is emptying the block in to the bottom of the radiator, but getting no water back in return - as the engine runs, cold water gets pushed out of the overflow after a minute or two. The return pipe from the back of the head heats up, as does the by-pass branch that runs to the thermostat housing and the water pum, but nothing above cylinder head height.

Before I start taking things apart, does anyone have a working memory of how the by-pass system functions? The thermostat is the old style multi-fold bellows running on 2 rails. I can't remember whether it had a "bleed" hole as later waxstats did.

The engine is running fine, steady tickover, even compressions, no evidence of oil in the water or water in the oil (so head gasket seems sound). Easy option I guess is simply to remove the thermostat, but since the water expulsion happens before the thermostat housing has got warm, I'm thinking there a passage that's blocked.

Anyone got any ideas?

Rubythursday
Posts: 36
Joined: Thu Oct 09, 2008 6:30 pm

Re: 1936 Ten Saloon Cooling system

Post by Rubythursday » Thu Nov 24, 2011 9:37 pm

Hi Mike
As the thermostat opens it closes off the bypass, my guess would be its blocking the bypass and the normal water.
Tony
York
Tony
1948 Rover 75, 1987 Range Rover Auto, 1987 Volvo 240 Auto 1999 Rover 75 Connoisseur Auto
http://www.tonysimons.me.uk

Mike M
Posts: 11
Joined: Thu Nov 24, 2011 6:21 pm

Re: 1936 Ten Saloon Cooling system

Post by Mike M » Fri Nov 25, 2011 6:18 pm

Tony,
Thanks for the reply and thought. I drained the system down this morning - crystal clear, fluorescent green antifreeze solution. Removed the thermostat housing and was amazed to find it packed with a part gel, part crystalline green deposit (gel looked just like Swarfega) completely blocking the main hose AND bypass port. Removed all the gunge from the housing and the thermostat assembly, confirmed that the stat opens (remains open in boiling water) and closes, re-assembled everything and ran the engine. No more Vesuvius factor from the radiator and things seemed even-temperatured. Next step is to get the car out in the open and leave it run until up to full working temperature. Anyone else had experience of "green gel"?

Rubythursday
Posts: 36
Joined: Thu Oct 09, 2008 6:30 pm

Re: 1936 Ten Saloon Cooling system

Post by Rubythursday » Fri Nov 25, 2011 7:43 pm

The ally housing is a pretty poor quality material and it could be the antifreeze is reacting with it and the disimilar material of the stat.
Tony
1948 Rover 75, 1987 Range Rover Auto, 1987 Volvo 240 Auto 1999 Rover 75 Connoisseur Auto
http://www.tonysimons.me.uk

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paul williams
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Re: 1936 Ten Saloon Cooling system

Post by paul williams » Fri Nov 25, 2011 9:03 pm

Hi Mike,

the FBHC has published an article on different antifreezes, they go through the different types. The 'green' type is not recommended for vintage engines. The full FBHVC newsletter is available at

http://fbhvc.co.uk/files/2010/02/fbhvc-ver4.pdf

Paul

Paul Williams
1929 2litre Saloon
1947 P2 16HP
1951 Rover Cyclops
1958 Rover P4 90 Monte-Carlo Rally Car
1998 LR Discovery I
1974 P6 3500


Mike M
Posts: 11
Joined: Thu Nov 24, 2011 6:21 pm

Re: 1936 Ten Saloon Cooling system

Post by Mike M » Sat Nov 26, 2011 12:20 pm

Hmmm. OK - the stat housing is of some crude alloy, the casting elbow on the back of the head is similar (but has nothing inside it). I've had previous problems with mazak door exterior handles which wouldn't rechrome. I'd left the antifreeze in whilst the car was dry-stored (but not frostproof) during the house build - the car had to be moved from time to time over 11 months. I might have fared better storing the car drained-down.

Now that the stat housing is clear and the by-pass back in action, I need to get my mind round the circulation process. The closed thermostat (against the radiator header tank) leaves the bypass orifice at the bottom of the housing open, so that the water pump (running clockwise) pushes coolant through the cylinder head and out of the back elbow in to the return pipe and back along the by-pass? When the head & by-pass system is hot enough, the stat opens, restricting the by-pass orifice until all the coolant is up to temperature, when the circulation excludes the bypass completely, but incorporates the radiator? Have I got it right?

The plan is to run the engine to get everything up to working temperature - I have an infra-red "pointer" thermometer, so I can identify any 'hotspots', but having an external by-pass (as opposed to the later 'enclosed' systems where the stat shuts and leaves coolant circulating within the block and head) is a concern. Whilst things were apart, I measured the depth of the by-pass 'orifice ring' from the stat rim, the amount of movement of the stat from closed to fully open; it seemed to me that even when the stat is fully open, the copper sleeve will not close off the by-pass fully and with the gap in the open thermostat being quite small, the by-pass loop will remain in circuit. Again, I guess if that's a problem the thermostat can be left out - even though that would mean lengthy warm-up times.

On a completely different matter, when I was last running the car, I had problems every 10 or 12 miles. The car would simply stop. The cause proved to be carburettor main jet icing. I had been getting vaporisation using the block-mounted AC pump and fitted instead an SU electrical "puller" pump,running the car without the paxolin spacer below the carb. The realisation came when there were beads of condensation on the outside of a VERY hot carburettor throat. As the spindle bushes were worn, I've since had the carb refurbished and replaced the carb insulator, so once I'm happy that the cooling system is up to scratch, I'm hoping that the "10 miles, then stop - restart 5 minutes later for another 10 miles" scenario will have gone.

As ever, any comments/thoughts welcomed.

chris dancey
Posts: 386
Joined: Tue Oct 20, 2009 8:20 pm
Location: Brighton & Paphos, Cyprus

Re: 1936 Ten Saloon Cooling system

Post by chris dancey » Tue Nov 29, 2011 4:26 pm

Hello Mike,

I may be able to help with some of your problems. The cooling system is as you state, I think that you need to obtain one of Mike Couldry's ( Meteor Spares ) adapted thermostats which should solve the problem.

Regarding the carb, and vapourisation, this is indeed a problem with modern fuels. The answer is the modification that you have already fitted ( SU pump ), but it also helps if the supply pipe from the ac pump that runs behind the exhaust manifiold is rerouted to a position which runs vertically behind the cooling fan. To maintain originality it is possible to remove the internals of the ac pump, make a stainless blanking plate so that the upper part of the pump becomes an empty chamber, its then possible to turn the top about 45 degrees, the inlet then becomes the outlet and vice/ versa, so the outlet then faces forward, run a new piece of pipe from here to the carburettor just behind the fan, its also possible to cover this pipe with exhaust tape if one wishes, but I found this unnecessary. If you are not aware i am in the process of a nut and bolt rebuild of my 1934 '10 ' and I also have a 1935 ' Barn find ' 10 that is totally original, has never been restored or indeed altered in any way, this is my standard for the resto on ' Snowdrop '. I have suggested the AC pump blanking plate be made in stainless as this will not be affected by ethanol. If you complete this modification, its a good idea to use the diaphram as a gasket, cut out the pushrod / centre section and fix above the plate, this will give the appearance of the tab for originality. I have dismantled every single nut, bolt etc, the chassis, engine, gearbox, rear axle, complete replacement of the Luvax system with new ( article in Freewheel soon ) and replaced, I am now restoring the bodyshell which has a fair amount of rust damage.If any problems contact me 01273 882593. I am in Cyprus at the moment, back on the 15 December...my Cyprus no. is 00357 26654617 if urgent. Regards, Chris dancey
1934 ( 1935 model ) P1 '10' Saloon RD 6160
1935 P1 '10' Saloon ( originally JB 6729 ) now VSJ 156
1946 P2 '14' Sports Saloon KPG 855
1933 MG J2 Cycle Wing Model APB 560
1933 MG J2 Competition Model ALX 124

Mike M
Posts: 11
Joined: Thu Nov 24, 2011 6:21 pm

Re: 1936 Ten Saloon Cooling system

Post by Mike M » Wed Dec 14, 2011 9:34 am

OK - thermostat housing cleaned out and system flushed (no more green antifreeze), the engine will run happily (fast tickover) for over half an hour. By pass system is working - heats up fairly promptly until stat opens and brings in the radiator until the whole cooling system is more or less at the same temperature (85 degrees in the water pump elbow, 79 degrees at the elbow at the back of the head). I'm confident that there's decent circulation.

Just so I can get my mind round the process, does the water pump push or pull coolant through the head = which direction is the flow? Commonsense suggests cooler water needs to be forced in from the bottom of the rad, but the pump only connects with the header tank - the hotter end of the rad.

Rubythursday
Posts: 36
Joined: Thu Oct 09, 2008 6:30 pm

Re: 1936 Ten Saloon Cooling system

Post by Rubythursday » Thu Dec 15, 2011 5:52 pm

It is in the hot flow to the header tank. Unusual as most pumps are in the cold side.
Tony
1948 Rover 75, 1987 Range Rover Auto, 1987 Volvo 240 Auto 1999 Rover 75 Connoisseur Auto
http://www.tonysimons.me.uk

Mike M
Posts: 11
Joined: Thu Nov 24, 2011 6:21 pm

Re: 1936 Ten Saloon Cooling system

Post by Mike M » Sun Dec 18, 2011 10:04 pm

Tony,
Thanks for that. Common sense was that the hot flow from the motor wouldn't be delivered to the top of the radiator, surely? But that was what appearred to be the physical set up - presumably evacuating the head from the front draws cooler liquid from the bottom of the rad in to the back elbow. Anyways up - running the engine over a reasonable period, the whole system appears to settle for an 82 degree "all over" temperature.

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