still boiling over
Discussion
Changed water pump ,temperature sensor to ecu ,and otter switch but the fans are still not coming on, only if I short them.Swirl pot gets hot but not untouchable ,same with the top hose to rad.The hose from engine to swirl pot is very hot at a lost ,the last thing to change is stat,bled the coolant so I don't think its an air lock.
Either fix what you got or get a aftermarket solution to control the fans (whats I'd do)
Like this lot for example
http://www.summitracing.com/int/search/department/...
Like this lot for example
http://www.summitracing.com/int/search/department/...
paul ds said:
Changed water pump ,temperature sensor to ecu ,and otter switch but the fans are still not coming on, only if I short them.Swirl pot gets hot but not untouchable ,same with the top hose to rad.The hose from engine to swirl pot is very hot at a lost ,the last thing to change is stat,bled the coolant so I don't think its an air lock.
These cars can be frustrating at times, and it is best to stop and start all over.The RV8 flows cold water from the bottom hose via the pump, around the block and up to the heads and inlet manifold. The only way it can cool is its passage through the thermostat [when it fully opens] into the swirl pot and back to the rad, via the top hose to be cooled in the radiator.
When the car is still, as stuck in traffic, there is no cold air flow thru the rad so the temp starts to rise.
When this reaches a certain point, usually a standard 92 degrees, the otter switch kicks the electric fans in drawing cool air thru the rad mechanically.
Thinking your problem out logically,
The water is not returning to the rad to be cooled as quick as it should be....your thermostat is not fully opening..... water in the swirl pot will be cooler than the water in the engine block....hence the otter switch will not make contact and turn on the fans.
The pressure and temp within the engine will rise, the water will boil,and some of the heat will eventually transfer back to the radiator via the bottom hose, thru the rad into the top hose,giving you a false sense that the water is flowing thru the top hose as it should....because as you say.......... the top hose is hot!
By this point the pressure will be sufficient to travel thru the small hose to the expansion tank, thus raising the level.Expansion cap will blow and coolant loss all over the floor.
Renew the thermostat a.s.a.p and bleed the system thoroughly. A good way to bleed the system is as follows
Keep the cap on the expansion tank, the nut nipped up tight on the swirl pot, and the bleed nut on the rad closed and now....remove the top hose off the top heater pipe, the one from the pipe to the inlet manifold. Loosen the jubilee clip on the manifold and turn the pipe thru 180 degrees and stick a funnel in the open end. This is now your fill point and it is higher than anything, anywhere within the engine and cooling system.
AS you fill undo the nut on the rad and bleed air until coolant only comes out. Refit and tighten the nut.Thats the rad sorted. Keep filling until coolant comes out of the now open end on the top heater pipe. Thats the heater matrix and engine block all bled. Only now undo the cap on the expansion bottle and as you fill thru your high point funnel air and then water will start to rise up the expansion tank. Most chimaeras only like about an inch or two in the bottom of the expansion tank.
Now undo the nut on the swirl pot and check the level, and it should be full.
Run the engine wait till the fans kick in, turn off and allow to cool then recheck the level in the expansion tank.
I had a few problems with cooling, but mine was a few tiny leaks in the rad, almost invisible, but would cause me no amount of grief after running the car for a while.
These cars can be a pig to fully remove all the air, but the way i describe above is one of the best ways to do, if not a little time consuming.
Good luck and keep us posted.
paul ds said:
.....and otter switch but the fans are still not coming on, only if I short them.....
This says to me that your otter switch is no good. If the fans come on when you short the otter switch connections together, then the otter switch is not doing it's job. Just because a new part is fitted, it doesn't mean it will work.
Try another otter switch - from a reputable source ( I am not saying your replacement one wasn't, by the way).
You can test an otter switch in much the same way as a thermostat, except that it closes a circuit when it gets to certain temp - should be stamped on the side of the switch - rather than opening like the thermostat does.
HTH Ged
Had a similar problem which baffled me for a while. To be brief the new otter switch was faulty changed it and system is now cooling fine. Did check switch in hot water with a ohm meter and a digital thermometer it appeared to work as expected but on the car it was useless. Changed it for another new one no problems now.
jeffwithaj said:
Had a similar problem which baffled me for a while. To be brief the new otter switch was faulty changed it and system is now cooling fine. Did check switch in hot water with a ohm meter and a digital thermometer it appeared to work as expected but on the car it was useless. Changed it for another new one no problems now.
^^^^^ Try this first!!!! 
tonys said:
Is the small bore hose between the swirl pot and header tank clear; there have been some reports of the connection at the base of the header tank being blocked with 'crud'.
Presumably the correct temp otter switch?
This was a problem on my car. Level looked Ok but it wasn't getting into the system so maon system was low but the header looked fine.Presumably the correct temp otter switch?
ok all thankyou for all your contributions have now taken off the thermostat and tested said item ,and woe and betide tested it and it does not open at all ,so I have bought water pump,sensor to ecu ,otter switch all for nothing ,lesson here is check the simplest things first and save a fortune ,will keep you posted on outcome as waiting for stat to be delivered.
paul ds said:
ok all thankyou for all your contributions have now taken off the thermostat and tested said item ,and woe and betide tested it and it does not open at all ,so I have bought water pump,sensor to ecu ,otter switch all for nothing ,lesson here is check the simplest things first and save a fortune ,will keep you posted on outcome as waiting for stat to be delivered.
Welcome to the world of TVR ownership 
Don't be so hard on yourself. You now have a new coolant temp sensor, new otter switch and a new water pump.
I have just fitted a new cam, so while the engine is out, i also fitted a new water pump, new clutch, new exhaust gaskets, new timing gears and chain, new engine and gearbox mounts, and lots of other smaller stuff.
Clutch was servicable and the water pump was perfect. Engine mounts were intact but had sagged a little with age. [bit like the wife, very glad she doesn't read this forum]....but as a Tvr owner, to save any future problems ....its what you do.
TJC46 said:
paul ds said:
ok all thankyou for all your contributions have now taken off the thermostat and tested said item ,and woe and betide tested it and it does not open at all ,so I have bought water pump,sensor to ecu ,otter switch all for nothing ,lesson here is check the simplest things first and save a fortune ,will keep you posted on outcome as waiting for stat to be delivered.
Welcome to the world of TVR ownership Don't be so hard on yourself. You now have a new coolant temp sensor, new otter switch and a new water pump.
I have just fitted a new cam, so while the engine is out, i also fitted a new water pump, new clutch, new exhaust gaskets, new timing gears and chain, new engine and gearbox mounts, and lots of other smaller stuff.
Clutch was servicable and the water pump was perfect. Engine mounts were intact but had sagged a little with age. [bit like the wife, very glad she doesn't read this forum]....but as a Tvr owner, to save any future problems ....its what you do.
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