6 replies to this topic

[SolarB]

During these cold nights my heater is not giving out enough heat to keep the car warm. The engine temperature is up to around 90 degrees and the heater has a new core, hoses and valve (which is fully open) but at best all I get is warm air.

I realised last night that if I change down a gear but keep the speed constant the heater instantly produces more heat, although the engine stays the same temperature. I assume there's more resistance in the heater circuit than the radiator circuit and that at my normal speed the majority of the water prefers to flow through the radiator, while increased water pump speed forces more water around the heater.

The car has a 2.9 diff which means for most of my commute the engine is only turning at 2000-2500 rpm which would appear to be a little slow to force the water through my particular heater setup.

I can think of two solutions to this problem.
a) Drive faster when it’s cold.
b) Fit an undersized pulley.

While solution (a) may be attractive solution (b) might be more practical as an undersized pulley would spin the pump faster and solve my problem without requiring constant overtaking.
I can find lots of oversized pulleys for racers but no undersized ones. I don't keep high revs for long so cavitation isn't a problem that the car will encounter. Has anyone ever seen a smaller pulley?

[Carlos W]

How old is the water pump?

I had a citreon AX where the impeller blades had corroded away!

I wonder if a new pump may increase flow through the heater matrix?

[lrostoke]

check out the list of pulleys on Somerford

http://www.somerford...page=page&id=97



If you've not used there site before if you hover over the number next to the part it brings up a list of part choices

Although it may be the pump at fault, my car runs the 2.9 diff and anything above tickover warms the heater up. Mostly standard 1984...998

Edited by lrostoke, 18 January 2012 - 05:50 PM.

[bmcecosse]

The smaller pulley will work well - and aid cooling in summer. It was fitted for many many years on A35/Minor and early Minis.

[thebullet]

One was fitted to mine and when it is revved high it will cool it down quicker because it spins the fan faster.

I just hate the noise it makes though!

[Dan]

Hard to say as you haven't said what size is fitted now.

[SolarB]

Thanks for the replys.

The pump is new so at the moment I'm believing it's OK. The engine is from an MG Metro and I assumed it was a standard pulley but I'd better go and check now it's daylight.

Somerford list two sizes and one is obsolite, when I know what size I have I'll have a hunt.