passat 130 tdi cooling system

hello lads back again i drove my car for six hours solid yesterday i use the car for a taxi i pulled into a garage to check the water and the water in the expansion tank was freezing i took off the cap and there was zero pressure the temp gauge was normal the heaters were normal i tried bleeding it today pulled the pipe back to expose the bleed hole lifted the expnsion tank but no water came out till i squeezed the hoses it woulnt just run out freely also the return hose shows no sign of water until i squeeze the hose i thought maybe the water pump but if the pump was knackered wht would the heaters be getting hot any suggestions would be really appreciated also its had a new cylinder head fitted by vw and the problem started 3 days later could it be linked i tried bleeding with engine not running and running it made no difference cheers for reading this bill

My system was not bled properly at first when I put it back together and so the heater was not working properly, contrary to your experience. When I drained the system it seemed to have left a plug of coolant behind in the heater that was released when I refilled it without initially bleeding. It appeared to be full but the heater not working gave it away and I had to add another 1.5L during the bleed process.

I lifted the header tank and bled without the engine running. Then ran the engine for 5 minutes and topped up. It has been OK since.

There should be pressure in the header tank if it is getting up to temp - but in the cold spell it is possible that it is not and may be affected even more by a thermostat stuck open. Can you feel any warmth at all in the radiator ?

You might want to try blanking off part of the radiator while driving and see if you can get any increase in temperature. If so then I would suspect the thermostat.

I have to run my land rover with the rad blanked off almost completely as it runs cold otherwise - just a fact of life !

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Originally Posted by passing

My system was not bled properly at first when I put it back together and so the heater was not working properly, contrary to your experience. When I drained the system it seemed to have left a plug of coolant behind in the heater that was released when I refilled it without initially bleeding. It appeared to be full but the heater not working gave it away and I had to add another 1.5L during the bleed process.

I lifted the header tank and bled without the engine running. Then ran the engine for 5 minutes and topped up. It has been OK since.

There should be pressure in the header tank if it is getting up to temp - but in the cold spell it is possible that it is not and may be affected even more by a thermostat stuck open. Can you feel any warmth at all in the radiator ?

You might want to try blanking off part of the radiator while driving and see if you can get any increase in temperature. If so then I would suspect the thermostat.

I have to run my land rover with the rad blanked off almost completely as it runs cold otherwise - just a fact of life !

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thanks for reply mate i drove it yesterday for about an hour and half and the bottom hose was cold the top one was hot can i just ask ,when you bled yours did the water run freely out the bleed hole cos when i tried to bleed mine the water woulnt come out unless i squeezed the pipe also do you know what that sensor is on the bottom hose i think its a sensor theres a couple of wires going to it cheers bill

top hose hot sounds good.

With the header tank above the bleed hole the coolant was flowing out quite freely. Assume you have new coolant and no crud blocking the hole ?

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Originally Posted by passing

top hose hot sounds good.

With the header tank above the bleed hole the coolant was flowing out quite freely. Assume you have new coolant and no crud blocking the hole ?

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hi its had anew cylinder head from vw with the proper coolant i lifted the header tank above the bleed hole i even took the pipe off and there was no water coming out till i squeezed the top hose is it normal for the bottom hose to be cold when the engine is hot ? cheers bill

Has this started ever since you had the head replaced by vw??

Hot top hose sounds good, cold bottom hose sounds too good, would expect cooler bottom hose, not cold. You have to check all the coolant lines and ports also the thermostat. I never fitted a new head but many valves and manifolds on industrial equipment, they all come with blanking plugs in the ports, maybe they left one in when they fitted your new head, if lifting the header tank produces no flow the out let/inlet pipe is not connected to the rest of the system, bleed hole is clear as it passes when hose is squeezed. If the bleed hole is covered does the level rise in the header tank when a hose is squeezed, I think it should.

second the post above - I would expect the bottom hose to be warm rather than cold of the system was warmed through. Based one xperience with other cars as I have not actually investigated my Passat.

Likewise if you squeeze the hose the level should rise in the header tank.

Interesting thought about the leftover plugs restricting / blocking flow. I'll keep my fingers crossed but with the standards of some mechanics these days it is worth investigating. I have my fingers crossed for you.

thanks for all the replies lads ,i wonder if a plastic cap has been left on the problems started 3 days after it was fitted ive had it back to vw and they dont know whats wrong with it i hope i get it sorted cos i love the car if i leave the heaters off the bottom hose starts to warm up i found another fault with it last night ,i went to adjust the drivers side mirror and both mirrors were moving could that have anything to do with it cheers bill

When my water pump went the engine temp gauge behaved as normal. The only indication was when we had a hot day the climate control was blowing out hot air no matter what temp it was set at.

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Originally Posted by billza1967

hello lads back again i drove my car for six hours solid yesterday i use the car for a taxi i pulled into a garage to check the water and the water in the expansion tank was freezing i took off the cap and there was zero pressure the temp gauge was normal the heaters were normal i tried bleeding it today pulled the pipe back to expose the bleed hole lifted the expnsion tank but no water came out till i squeezed the hoses it woulnt just run out freely also the return hose shows no sign of water until i squeeze the hose i thought maybe the water pump but if the pump was knackered wht would the heaters be getting hot any suggestions would be really appreciated also its had a new cylinder head fitted by vw and the problem started 3 days later could it be linked i tried bleeding with engine not running and running it made no difference cheers for reading this bill

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