hi

  im a new member on here. i wonder if anyone can help with this problem. the car is 2009 octavia

1.9 tdi est. bxe engine. it does not have climate control just the manual adjustment  the heater goes

cold after driving for a while it heats up quick enough but goes cold mainly when on tickover. 

i have changed thermostat

replaced heater matrix

replaced water pump with dealer part

bypassed water jacket on egr valve

removed pollen filter

flushed out 6 times

blew out with compressed air

blew and sucked allrubber heater pipes by mouth

checked diverter flap and motor are free and moving with control ok.

installed eliots head and block crack sealer also seals dodgy head gaskets

done a test with universal blocktester on water filler the one with the bluefluid which changes colour if it detecs any gas in water

it checks out ok.

the cooling system works perfect heats up ok fan comes on & off gauge stays on 90 ok.

no bubbles visible in water 

no sludge in or contamination in oil or water

 

no steam or water out of exhaust  im a bit stuck now. thanks for any help       eddy

hi 

 just a update on this fault. it was the cylinder head although there was no other symptoms. i 

removed it and got it machined flat. heater works ok now.