Cool air from blower - water pump ?

[taylormj4]

Getting only luke warm air from the blower even when water temp at 90degC with the fans on when at tick over. However, if I rev the engine the blower air temp rises to the usual hand-melting level.
I have had this before when coolant level dropped very low due to radiator leak. Radiator replaced a year ago and problem solved. Checked coolant and it is usual level in top up tank (around 1-2inches from the bottom).

Does the relation to revving suggest a failing water pump or is it trapped air in the system. I have tried topping up the coolant level but no difference.

[Tyre Tread]

Check that the outlet from the expansion/filler tank isn't blocked. Mine was and needed a drill through it to clear the corrosion blocking it.

Other than that I would suspect a blocked heater matrix.

[WOO5IE]

You could also check the heater valve is fully opening.

It on the passenger footwell high up behind the carpet on the left by the door hinge.

[spend]

WOO5IE said:

You could also check the heater valve is fully opening.

It on the passenger footwell high up behind the carpet on the left by the door hinge.

Just feel the pipes (all 4) to check water temp & flow, can even trace them into the engine bay & inelt manifold + swanneck/pump (serp/preserp). You can also get a good idea of the pump by revving the engine (flick the linkage) whilst holding the top hoses, you'll feel the pressure if its pumping.

[bigdods]

Dont rely on the expansion tank, to check the level remove the stopper from the swirl pot, the water level should be right to the top. Obviously make sure the engine is stone cold first.

Could be an airlock of some kind, if I had this problem I would start by checking the swirl pot then bleed the cooling system.

I cant recall, is the water pump driven from the aux belt ? if it is check the belt is tight.

[rickprice]

In mine this used to signify that I had lost water.

EVentually discovered valley gasket was leaking, but thats another story.

Rich

[taylormj4]

Well, I found the reasons for the strange behaviour. I followed the filling method suggested on here and in SHpub's book and found I had to add near 3 litres of coolant. Pretty impressive that the car has been running without overheating with only around 75% of the required coolant level. Even in traffic I was only seeing temps of around 95degC, or can the coolant temp sensor give incorrect readings under loss of coolant conditions ?

Next problem is to find out where the coolant was lost from. No puddles under car and radiator was replaced around 18months ago. Hmmm....

[Harrytsg]

If you can, pressure test the cooling system, it should show the leak. Also this has the added advantage of working around the engine while its cold.

Steve heath does an adapter for the swirl pot to do this.
https://delta.securesslhost.net/~shenglt/catalog/p...

[Tyre Tread]

taylormj4 said:

Well, I found the reasons for the strange behaviour. I followed the filling method suggested on here and in SHpub's book and found I had to add near 3 litres of coolant. Pretty impressive that the car has been running without overheating with only around 75% of the required coolant level. Even in traffic I was only seeing temps of around 95degC, or can the coolant temp sensor give incorrect readings under loss of coolant conditions ?

Next problem is to find out where the coolant was lost from. No puddles under car and radiator was replaced around 18months ago. Hmmm....

It might not have lost any. Was it filled properly when the rad was replaced?

[darkcat]

i wouldnt worry till winter :-D

[Harrytsg]

Tyre Tread said:

It might not have lost any. Was it filled properly when the rad was replaced?

This is a good point, did you check the level between the new rad being fitted and now?

[taylormj4]

darkcat said:

i wouldnt worry till winter :-D

My main concern at the moment is the engine overheating rather than whether I can keep my toes warm but I see your point.

[taylormj4]

Harrytsg said:

This is a good point, did you check the level between the new rad being fitted and now?

Yes but I checked at the top up/"header" tank, not at the swirl pot and assumed that it had been filled properly. I guess I'll have to wait and check the water level in the swirl pot after another week of driving or so.

[Tyre Tread]

taylormj4 said:

assumed

Ah!

[bigdods]

FWIW I have found that even when properly bled I still need to check the swirl pot for the next 2 or the drives and top it back up, usually just a cm or so each time.

[taylormj4]

bigdods said:

FWIW I have found that even when properly bled I still need to check the swirl pot for the next 2 or the drives and top it back up, usually just a cm or so each time.

Ok, will do, thanks.