Technical heater isn't very hot

[helicopterandy]

is there any simple way of making the heater blow hotter air?

when i'm driving normally it gets a bit warm, but doesn't get hot unless you run the engine at higher revs than i want to routinely do...then it gets as hot as i'd expect it to...

 

[fingers99]

It should be fine. On an 899 (especially) it may be a sign of a water pump (or entire cooling system) on its last legs.

In any event, bleed the system.

 

[Pep0]

replace thermostat and if it is 899 water pump
flush system with garden hose in header tank and bottom hose removed from rad
may be better to remove rad and flush it with garden hose in both directions
new coolant at least 20% antifreeze bleed at both bleed points
check the fan runs by shorting the pins in the cable to the rad switch
run the auto until the fan cycles on and off twice

 

[helicopterandy]

system was drained and refilled last year by my mechanic as part of fixing a leak in the system and the fan runs encouragingly so sounds more like the water pump.

thanks peoples

 

[portland_bill]

Thermostat is likely culprit, if it is stuck open or partially open. Engine is running cool, so is heater. When engine works hard, more heat is produced, which is what you're feeling.

From cold, start engine. Top hose should stay cold as engine warms, then suddenly get hot as thermostat opens. If it warms gradually, thermostat is open early. Replace.

As said above, make sure system is properly bled. IIRC there's a bleed screw on the upper heater hose, and another somewhere. Need to find both, bleed the lower one first.

 

[ycming]

That happened to me, it was down to the heater matrix radiator needing a flush !

Ming

 

[helicopterandy]

I'll try starting from cold to check that hose.

Thanks folks