Bit of a conundrum this one. Sounds for all the world like an air lock. It is not overheating and not ejecting coolant due to over pressuring of the system by exhaust gas. But it is pressurising the system to make the hoses hard and coolant is being sucked out of the tank when the engine is running. Which does sound like an airlock. He should first check his plugs, if there are no clean ones, then it is safe to assume no coolant is entering the cylinders. He may well have a slight undetected leak because of the overpressure that dries as it escapes. That is why i say static test it. Just wondering if the heater hoses are connected the wrong way round, which is causing an airlock and the pressurising. If he does have a combustion gas leak into the coolant you would expect the motor to overheat and expel coolant after a time. It does not seem to do this, so at this time it seems safe to assume there is no combustion gas entering the system. It is a strange and interesting problem.

Wammers i have something in my mind dunno hun.listen i have replaced the throttle warmer under the plenum now there is 2 hoses an intake and the other that throws coolant back the bleed pipe to the exp tank,is it possible that the feker put them the wrong way arround?so it is sucking from the tank instead of throwing there?i wish u can tell me how they must be connected to the plenum,there is 2 small nipples lol under the plenum left and right or up and down dunno can u draw it?which one sucjs and wich one throws?

jorjio_k said:

Wammers i have something in my mind dunno hun.listen i have replaced the throttle warmer under the plenum now there is 2 hoses an intake and the other that throws coolant back the bleed pipe to the exp tank,is it possible that the feker put them the wrong way arround?so it is sucking from the tank instead of throwing there?i wish u can tell me how they must be connected to the plenum,there is 2 small nipples lol under the plenum left and right or up and down dunno can u draw it?which one sucjs and wich one throws?

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Study RAVE coolant diagrams for your engine. Make sure every hoses is connected as per RAVE. It really does sound like you have an airlock in there somewhere. More likely than not in the heater circuit. If coolant is not flowing in the right direction air pockets will be formed. As the coolant heats they expand and cause pressure build up. Worth a try mate.

Think about it. If you have an engine block, heater and rad full of water no water can be sucked in. For water to be sucked in when engine starts there has to be a void somewhere for it to fill. Highest part that stores water is heater matrix. That is where i think you have an air lock. Check the heater hoses are in correct position. Heater hose from block goes to top inlet on heater. Bottom connection on heater goes back to thermostat housing.

wammers said:

Think about it. If you have an engine block, heater and rad full of water no water can be sucked in. For water to be sucked in when engine starts there has to be a void somewhere for it to fill. Highest part that stores water is heater matrix. That is where i think you have an air lock. Check the heater hoses are in correct position. Heater hose from block goes to top inlet on heater. Bottom connection on heater goes back to thermostat housing.

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The hoses are inserted as you have said in the correct direction.my head hurts now wammers,cooling system hoses and stuff are as mentioned in rave,i took the laptop with me and checked everything,either he ****ed something up in the heads either it is the block.coolant started dripping from the vent now but no overheating at all,the gauge is 2 mm.above center,i told u this car is posessed and jinxed how come a pro like that doesn't have a solution?what is that planes engineering hell it is just an old v8 not a dilema.......

jorjio_k said:

The hoses are inserted as you have said in the correct direction.my head hurts now wammers,cooling system hoses and stuff are as mentioned in rave,i took the laptop with me and checked everything,either he ****ed something up in the heads either it is the block.coolant started dripping from the vent now but no overheating at all,the gauge is 2 mm.above center,i told u this car is posessed and jinxed how come a pro like that doesn't have a solution?what is that planes engineering hell it is just an old v8 not a dilema.......

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If it has combustion gas going into the coolant it must be very,very slight. Or it would blast the coolant out in a very short time indeed. Decision time for you i think mate.

Have you tried bleeding the cooling system as wammers said it sound like an air lock in the system