Heater woes

[F2eeman]

Right, fitted a new OE heater control valve earlier today as it was stuck on cold... started her up and it warmed up good and proper... not face meltingly hot, but hot enough! .... Anyway, just took it out for a spin, engine heated up, car heated up fine... untill I took it past 40mph... as soon as its going about 40+ it just gets 'room temperature' air coming out. Tried recirc, just the same, checked for leaks at the hcv etc, all fine. I'v a dangerous amount of knowledge about cars (enough to have a bash at anything, but not enough to prevent explosions!) Could it be thermostat or something? .... temp gauge indicates just below half way. Any help would be muchos appriciato! :roll:

TIA

edit: Just checked pipes to hcv and they're all hot, BUT noticed the faster I'm going the temp gauge does actually drop quite abit, think I'll try thermostat if no one has any other thoughts...

 

[martinthrapston]

thermostat is stuck open.

 

[Anonymous]

If you've changed the HCV the system may need more bleeding/settling down. Pumas are known for being hard to bleed. I had your symptoms when i changed mine.
It may be worth keeping an eye on it for a few days and tossing up the coolant as necessary before you go steaming in to change the thermostat.

 

[F2eeman]

Thanks guys, not going to be able to do the thermostat until weekend anyway, maybe it will fix itself by then

It's swallowed a lot of water when I took it out this morning so filled it up (about a litre) and heating seems to be working at any speed now, although its now ultra hot it seems hot enough, though the engine temp does seems to vary quite a bit still... but unless its supposed to be bang on 1/2 on the gauge all the time even in cold weather (usually just below or sometimes at 1/4 depending on speed) then I think its problem sorted!

 

[martinthrapston]

if its sitting at below 1/4 or less usally means thermostat is stuck open,and also can affect fuel economy as the ecu thinks the car is still not warmed up properly so is making the engine run richer than it should be.

 

[Anonymous]

Just noticed you said earlier that the faster you go, the cooler the temp.
If you are going for a thermostat change it may be worth checking the radiator for blockages.
I replaced mine as a blockage was causing over heating at low speed/revs but cooled down once the revs went high enough.

 

[YOG]

The later 1.7 gauge, once up to operating temperature (around 86/87°), is at the vertical position and normally stays there.
Mine doesn't move from there, even up to around 106/107°, when the cooling fan kicks in (IIRC).

 

[F2eeman]

Well with more driving it seems at a constant steady speed engine temp stays roughly at half way, never over heats though. But if I accelerate quickly up to say 60-70 the temperature drops quite quickly. I do think it needs a new thermostat, just looked at the how to and it looks a right pig!