wonderseven Posted July 1, 2000 Share Posted July 1, 2000 I cannot get my new VHPD to pump water around the system. The car is fitted with a dry sump and heater. Coolant gets hot at the top of the rad/heater but the bottom remains cool. I am sure it is not air-locked as it was filled using the top heater hose. I've even tried jacking the car at different angles just in-case Any ideas? Edited by - andy_m on 1 Jul 2000 06:14:50 Link to comment Share on other sites More sharing options...
I.Mupferit Posted July 1, 2000 Share Posted July 1, 2000 Isn't that what is supposed to happen, hot at the top and cool at the bottom? As I understand it the hot water from the engine is pumped into the top of the rad. and cools as it passes down through the core to flow back into the engine. As heat rises it would be ineffective to pump it the other way round. Link to comment Share on other sites More sharing options...
wonderseven Posted July 1, 2000 Author Share Posted July 1, 2000 Not like this it's not supposed to be! The water in the bottom pipe is stone cold with the top of the rad boiling! Caterham seem to think it may be a sticking thermostat. Anybody had similar experiences? Link to comment Share on other sites More sharing options...
Robbo Posted July 1, 2000 Share Posted July 1, 2000 to check if it's the thermostat, take it out (preferably with engine cold!,re-fit housing and start engine. if water flows ok then it was a sticking thermostat. i have no experience with this engine but if the thermostat is in-line with the top hose, then i would be surprised if it was sticking (or the top hose would remain cold) Link to comment Share on other sites More sharing options...
wonderseven Posted July 1, 2000 Author Share Posted July 1, 2000 Thermostat is fitted in line with the bottom hose. Stupid, thinking about it, as this is the last place to get hot! On Caterhams advice I have run it several times allowing heat to "soak" through, and it seems to have done the trick. Anyone know what temp the VHPD is supposed to run at? Link to comment Share on other sites More sharing options...
CHRIS CLARK Posted July 2, 2000 Share Posted July 2, 2000 Andy, Can't say for sure what temp your eng. should run at but allowing for gauge error etc., the general area for the people I've had this conversation with is around the 80* mark. Anyone know better? Mine is this with a third of the rad. blanked off! Link to comment Share on other sites More sharing options...
Mike Bees Posted July 3, 2000 Share Posted July 3, 2000 I had the same problem as Andy on my first Caterham (1.4K) where the gauge went up to 100 with no sign of any flow. 'Phoned Caterham who said that it might need to get quite hot and/or be cycled a few times to get the thermostat to do it's first opening - they were right. Running temperature should be governed by the thermostat. It's an 88deg 'stat in the standard K, but the gauge isn't *that* accurate (the ECU reads 10deg hotter than the dash gauge on my car). If you blank off the rad then you will make it more likely that you're running with the 'stat fully open more of the time, and make it likely that the rad fan will have to cut in sooner. I can't see any advantage in doing this. If the radiator is over capacity then the 'stat should stop the engine from getting too cool - that's what it's there for. Mike Link to comment Share on other sites More sharing options...
CHRIS CLARK Posted July 3, 2000 Share Posted July 3, 2000 Mike, You are probably right as the fan now cuts in at a gauge reading of 82* ish where before it got to the 88*. It does though take a little while to drop where as before within thirty seconds the gauge was reading 70*!!!! To be honest, I'd like to fit a resistor to set the gauge to read central ie. 90* to just 'look' right! Any ideas? Link to comment Share on other sites More sharing options...
Tim Seipel Posted July 3, 2000 Share Posted July 3, 2000 The system must be fully bled. Initially fill from the top heater hose or bypass if no heater then through the expansion tank until it trickles out of top hose at radiator end (disconnected of course) then fir this hose, undo the top radiator plug and carefully add more until it trickles out of this plug hole. If you don't do the last stage, when the stat opens, there is not enough water to actually complete the flow circuit, hence no flow and a very hot pipe with a very cold bottom hose. Top up the expansion tank then start to run engine. If as the stat opens no flow comes out of the bleed pipe from the inlet manifold then remove the pipe from the manifold and using thin screwdriver or a bit of welding wire jiggle the ball in the end of the pipe (If fitted) scalding hot water should then squirt out. At this stage refit pipe and tighten clip. If you follow this fill process, then the system will have no air locks. NB This does of course assume that the cooling system is actually plumbed in correctly. My advice on the high output K engined vehicles is to encourage the stat to be in an open condition or like the racers use, drill it or jack it. There will be more on this subject in a short while. That I can promise!!! Link to comment Share on other sites More sharing options...
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