Hi all , 

I have a mk2 Octy 2009 1.9 tdi pd.

I am having persistant problems with the cabin heater , no hot air. Been to garage and they changed the thermosat. This has not solved the problem.

First thing this morning checked  the coolant level and was ok, however it was pressurized which i didnt expect Doesnt seem to be losing coolant and no mayo on oil filler.

The engine sits on 90c and the engine fan is always on, which it should be as its only 3c outside. If I boot it a bit above 3000 rpm I get hot air.

If anyone has any ideas of how I can solve this reacurring headache I would be very gratfull !

change your c/head gasket.

 

There is no loss of coolant, so would it still  be the gasket ?, I hope not 

1 hour ago, trc said:

The engine sits on 90c and the engine fan is always on

Well, there's something clearly not right somewhere.

 

All the gauge temperature proves is the gauge temperature; it tells us nothing about the temperature value on the EMS channel.

 

The fan running non-stop in these temperatures suggests either that the coolant is actually hot, but not so hot that VAG see fit to allow you to see the fact on the gauge, or that the fan thermo-switch is stuck on.

 

Lack of cabin temperature could mean that the thermostat is stuck wide open, or that the heater is stuck on "cold".

I already had the Thermostat changed

 

When was the water pump last changed?

Water pump and cambelt changed 2 years ago , has done 28k since

 

@trc - What I know about your car: what's already posted in this thread.

 

What I know more generally; everything in post #4 is a plausible diagnosis of one or both of your reported problems.

agreed ken , but had therostat changed , no differance  at all

The reason I said about your h/gasket, Check out this

 

Missing coolant - Skoda Octavia Mk II (2004 - 2013) - BRISKODA.url

 

Air/gases trapped in the heater matrix.  When idling the water pump does not force enough coolant in to clear it , when running hard the coolant is forced in and displaces the air/gas. The temp sensor does not get the temp. readings from the heater it  the temp. from the engine. 

Leaking h/gasket or faulty EGR cooler can cause this

 

Or the bypass pipe (small dia one) which goes from the cylinder head to the coolant filer tank is blocked

Just observed the following today,engine overheats on a run, and if I coast a bit on the downhill the temperature returns to normal, heater hoses seem hottish to the touch.

However , bottom rad hose is COLD , and top hose HOT fan also stays on. Thermosat has been replaced already.Not lossing coolant , so prob h?gasket ok.

@trc - That sounds like you have sludge in the bottom of the radiator. When was the coolant last changed, and it is using OAT (pink or orange) rather than glycol (usually blue, occasionally green) or a mix of the 2 types?

Prob last time coolant changed was 4 years ago when it had a cambelt and w/pump done,and it was orange coolant.

@trc OK, can you see coolant flowing through the expansion bottle/header?

Will check tomorrow in daylight , but cant say i have before . When i take cap off , after a while when heats up it level comes up and overflows.

Just to update , car has been to an independant dealer today and w/pump done , and brake caliper replaced .All done for £300 Car up to temp and all working thankfully !

So, it seems like a faulty water pump....

Yes, all fixed . Thankyou to all for your input.