4th gen heater probs

Post by **paul72** » Wed Oct 16, 2013 7:27 pm

The valve on bulk head will move but is stiff but it returns wen u let go plus found out today that top rad pipe was very hot an bottom one was cold for ages even after temp gauge was up to half but after 30 mins it then got hot so i take it its the thermostat sticking shut so going to try that next

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Wed Oct 16, 2013 8:00 pm

Thermostat sticking shut would give you an overheating engine, not cold heater.

Might as well change the thermostat since it's an easy/quick job and you need to get coolant in anyway, but while you have the system drained, give the heater matrix a proper good back and forward flush with full water pressure from a garden hose and the hose disconnected the other side of it.

Post by **Thebusofwoe** » Wed Oct 16, 2013 8:03 pm

^^^ this. Perfect answer IMO.

Post by **paul72** » Wed Oct 16, 2013 9:16 pm

Cheers guys will give it a go

Scott560 · Post by **Scott560** » Wed Oct 16, 2013 9:21 pm

Changing thermostat never hurt anyone. Did similar to a civic the other week and it has helped the heater no end, despite the guage staying at the same poisition (but deffo warming up much quicker now).

Ive had blocked heater matrixes on cars previously. When old antifreeze is drained out, silt tends to accumulate in the matrix and refilling doesnt always budge it. Hosepipe job and flush it both ways should rule out the matrix.