Help ! 300tdi Gushing Coolant ..

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Originally Posted by loanrangie

Do you know the history of the motor ,gasket and head ?
If its the original head my bet is on it being cracked.

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No history at all , I rescued this from a yard where it had been lying for some years . Two core plugs were missing from the block and one from the side of the head , there might be a clue there . With the plugs replaced the engine started easily and drove very well on the 4 miles home , although the temp gauge was starting to climb by the time I got there . What surprised me today was the way the engine could warm up but the heat didn't travel into any of the hoses . Failing any other solution , I'll have a sniff test done .

As far as I know, if the block/head are warming up and the water is topped up, the only way the hoses can still be cold is either a defective thermostat or pump.

Tom.

P.S you said you disconnected the fan - you didn't take the belt off did you?

Tom.

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Originally Posted by BathurstTom

As far as I know, if the block/head are warming up and the water is topped up, the only way the hoses can still be cold is either a defective thermostat or pump.

Tom.

P.S you said you disconnected the fan - you didn't take the belt off did you?

Tom.

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No , didn't take the belt off , just the fan ! Just wondering though , if the pump isn't working how is the coolant getting from the engine and rad to the header tank ? Remember it it will start to do this near enough straight away .

Did the motor get hot enough for the thermostat to open? it has to get to 88 degrees (I think) for a standard thermostat.


Tom.

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Originally Posted by BathurstTom

Did the motor get hot enough for the thermostat to open? it has to get to 88 degrees (I think) for a standard thermostat.


Tom.

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I let it run til gauge went just a shade past half way . Don't know exact temp though . New thermo is in correctly . It's behaving exactly as it did when I drove it home with the old hoses thermo and rad .

I fixed it ! ... briefly . Now it's only half fixed . Yesterday I ran it up to temperature , with the tank still overfilled , and the rad and thermostat housing still low and with bungs removed . Keeping an eye on the gauge I noticed it drop back a little to the cool side , at that point I carefully added coolant to the thermostat housing , when it stopped bubbling I replaced the bung then topped up the rad and did some hose squeezing and replaced the bung . Lo and behold the heat was traveling all round now , temp holding steady , heater working well and no hard hoses . Came back later and gingerly undone tank cap , just a bit of hissing but no spillage . The coolant had dropped from full to about an inch and a half less . Came back to it today , fished out the excess coolant and ran it up to temp , but on this occasion there was no drop in temperature and the heater and it's hoses and rad remained cold and only the hoses from the thermo housing to water pump and from behind the pump warmed up . On the plus side the tank level dropped slightly and hoses aren't going hard and coolant has not risen . So it's looking very much like a circulation problem . Could a new thermostat really be faulty ?

The thermostat could be the culprit.
Make sure it is fitted with the little hole at the 12.00
position. This lets the air purge.
The other culprit is the plastic 3 way connector and 1/4 hoses that connect the rad/thermostat/expansion tank. Make sure this has flow in all directions and is not blocked.
Even with the thermostat closed there is flow through these hoses.