It may be totally unrelated, but bear with me. My old Disco had a similar issue, was fine driving normally, but when loaded up with gear/trailer etc anything over 50 it would do exactly the same as your Fabia. Tried everything, rad, stat, flushed the system, none of it worked, until I found that there was an air leak into the fuel lines. Under normal driving it wouldn't cause a problem, as it wasn't pulling huge amounts of fuel, but when under full load, it would drag air in, weakening the mixture, and causing the temperature to rise rapidly to the point of boiling.

It may be worth checking fuel lines for damp patches, and also the fuel filter connections too.

That would make sense for a petrol engine, but the OP has a diesel.

That would make sense for a petrol engine, but the OP has a diesel.

 

Disco was a TDi - replaced a length of corroded fuel line that ran along the chassis with fuel hose and the problem never came back, even when bringing my vRS the 200+ miles from Middlesborough at 60 on the motorway

Disco was a TDi - replaced a length of corroded fuel line that ran along the chassis with fuel hose and the problem never came back, even when bringing my vRS the 200+ miles from Middlesborough at 60 on the motorway

Diesels don't, or shouldn't anyway, overheat because they're running lean. They do that any time they're not at full throttle.

It's rare for the pumps to fail, but I've heard of other VAG group pumps having issues with the plastic impellor slipping on the main shaft and not flowing enough

 

 

It's not a genuine water pump. It is a circoli water pump from ECP.

so can someone confirm the following:

- Does your return pipe to the expansion tank constantly flow water back to it?

 

Can anyone confirm this for me ... ?

 

Despite being run for 15 minutes... nothing comes out of the return pipe... not seeing much movement of water either in the system.

Can anyone confirm this for me ... ?

 

Despite being run for 15 minutes... nothing comes out of the return pipe... not seeing much movement of water either in the system.

That sound like the water pump has failed. On a 1.9TDi, changing the water pump means removing the cam belt, so you should change that rather than risk re-tensioning it, and that means it would be as well to change the entire belt kit and the tensioner unless they ere done in the last 2 years.

That sound like the water pump has failed. On a 1.9TDi, changing the water pump means removing the cam belt, so you should change that rather than risk re-tensioning it, and that means it would be as well to change the entire belt kit and the tensioner unless they ere done in the last 2 years.

 

 

Belt, Pump, Tensioners were all replaced 8-9 months ago!

Belt, Pump, Tensioners were all replaced 8-9 months ago!

In which case maybe take it back to the garage that did it, since the parts should still be under a VAG warranty.

In which case maybe take it back to the garage that did it, since the parts should still be under a VAG warranty.

 

I supplied the parts to the garage that did the work for me.

 

Belt kit was INA from ECP.

 

Pump was Circoli from ECP.

Edited 29 September, 20169 yr by Mr OCD