Cooling Problem
Discussion
Had a super 260 mile run to VSCC Prescott a week ago but on the Sunday after a brisk blast up the M5 from Gloucester (25 miles) and a decent A road I was held in a queue for 20 minutes waiting to park. The weather was warm and although the fans switched in it boiled. The worrying part was that a hose then sprung a leak in the passenger well spraying boiling coolant over my nice new carpet. Luckily no passenger but they would certainly have been scalded.
Fitting a heater cut off tap earlier this year:
http://bertram-hill.co.uk/grif.aspx
didnt help matters as with the water feed from the top of the engine blanked the heater could not be used to provide a bit more cooling. As an emergency repair I cut the long hose feeding the heater from the top metal heater tube at the back of the block and connected it to the other metal tube thus bypassing the heater completely. Topped up with water and it travelled the 260 miles home without event.
A more permanent bypass now connects the heater outlet from the top of the engine to the metal tube feeding the bottom of the radiator, it would be a simple matter to reconnect the heater if required. As the car is not used in the winter months I doubt whether a heater is really necessary, there is so much heat generated from the engine that the cockpit always feels warm. Apparently the later Triumph TR's had a similar heater arrangement and several passengers have been scalded. some TR owners have moved the matrix into the engine bay as a precaution. Interestingly my Swirl Tank always previously ran about half empty and has done so for 8 years quite happily. After bypassing the heater, the tank now runs near the top.
Fitting a heater cut off tap earlier this year:
http://bertram-hill.co.uk/grif.aspx
didnt help matters as with the water feed from the top of the engine blanked the heater could not be used to provide a bit more cooling. As an emergency repair I cut the long hose feeding the heater from the top metal heater tube at the back of the block and connected it to the other metal tube thus bypassing the heater completely. Topped up with water and it travelled the 260 miles home without event.
A more permanent bypass now connects the heater outlet from the top of the engine to the metal tube feeding the bottom of the radiator, it would be a simple matter to reconnect the heater if required. As the car is not used in the winter months I doubt whether a heater is really necessary, there is so much heat generated from the engine that the cockpit always feels warm. Apparently the later Triumph TR's had a similar heater arrangement and several passengers have been scalded. some TR owners have moved the matrix into the engine bay as a precaution. Interestingly my Swirl Tank always previously ran about half empty and has done so for 8 years quite happily. After bypassing the heater, the tank now runs near the top.
The swirl tank bit is interesting for sure.. I'm convinced that you always have air trapped in this matrix choose how hard you try get it out.. and it's this that set's the level... I ran for 1 year at 25mm from the bottom.. having had a good go at getting all the air out, this year I'm running around the 1/2 way mark.. As you say, remove the thing (and all it's air)... you may go higher.
Was thinking of disconnecting mine also but for the cold days with the top down (obviously).. It's nice to have it blowing on the old hands a bit!!..
Was thinking of disconnecting mine also but for the cold days with the top down (obviously).. It's nice to have it blowing on the old hands a bit!!..
Edited by TVR Beaver on Friday 20th August 08:48
I'd agree that there is air trapped somewhere. I drained my system about a month ago and have been removing air from the system ever since. Only small amounts but pretty much every time I try I get more air out, although it seems that the swirl pot does a reasonable job of catching it. Been doing this for about a month now and my expansion has reduced from about 2/3rds of the expansion tank between cold and hot down to about 1/2. Sure there is more to go yet but seems I'm getting there.
When the engine is cold I'll squeeze the top hose flat (both hands) or (more risky so be very careful) I slowly release the pressure in the system (very carefully undo the pressue cap until you start to hear air escape, then wait). The resulting expansion then pushes air out of the swirl pot. If I do this at hot I take the precaution of leaving hte cap loose until the engine is cold as I don't want to create a negative pressue in the system. Do be very careful though if you do release the pressure at hot, it isn't really advisable!
When the engine is cold I'll squeeze the top hose flat (both hands) or (more risky so be very careful) I slowly release the pressure in the system (very carefully undo the pressue cap until you start to hear air escape, then wait). The resulting expansion then pushes air out of the swirl pot. If I do this at hot I take the precaution of leaving hte cap loose until the engine is cold as I don't want to create a negative pressue in the system. Do be very careful though if you do release the pressure at hot, it isn't really advisable!
When the heater was operational I had considered fitting an air vent somewhere in the cooling system similar to the shrader valve arrangement in the Peugeot 106 and Citroen Saxo. Air pockets cannot be a good thing either for engine cooling or the heater. Now the heater is bypassed it no longer seems a problem.
Peugeot have some air bleeds on the 205 that consist of a small brass screw with a drilling up the centre and out the side of the thread near the top. This then is sealed with a fibre washer, easy to use but needs a chunk of metal to atach it to.
I suspect the system could do with several bleed points given my experience of trying to fill it!
I suspect the system could do with several bleed points given my experience of trying to fill it!
Bleeding through the pipe stubs that were your throttle heater is pretty much at the top of the engine/heads/manifold.
Convert to a remote stat ala cerbera and you get decent flow all the time... many of these problems are really working around the horrible paradox of the stat closing and bleeding as well IYSWIM.
Convert to a remote stat ala cerbera and you get decent flow all the time... many of these problems are really working around the horrible paradox of the stat closing and bleeding as well IYSWIM.
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