No Heaing

[latrine]

Morning all

 

had an overheating problem recently, whereby the temp guage kept moving on up towrds the redline when under load - if driving gently/round town, etc, the guuage kept rigidly at it's usual 90 degrees

 

took it yesterday for a new thermostat - guess what - now have no heating

 

i'm confused, because the temp guage still makes its way up to 90 degrees ok and sticks there (i've yet to drive the car hard to see whether the overheat probles is cured) but no heating!

 

i'm afraid i don't understadn the coolant system sufficiently to know why this would be

 

to my little mind, if the stat is dodgy (i don't know whether it should be open or closed to work the heating) then wouldn't the temp guage either just keep rising (because it's not allowing the heat to be removed) or, alternatively, wouldn't the temp guage stay on cold/low as it's allowing too much cooling to allow the engine to warm up sufficiently?

 

my confusion is, why does the car warm up to 90 degrees as normal but still no heating?

 

if anyone could give me an idiot's guide to the workingof the coolant system, that would be great

 

also, any ideas what the problem is?

 

I'll certainly be taking it back to the garage for them to have a look but i'd like an idea of the problem myself, rather than just leaving it to them to determine

 

i have faith in you all for the right answers!

 

cheers

[dipsomaniac]

when started from cold the thermostat is in the closed position only allowing the coolant to circulate the block. this allows the engine to warm more quickly. once the engine has warmed up the thermostat opens allowing the coolant to circulate through the radiator, heater matrix etc.

 

you could have an airlock in the heater matrix - i don't think there is a bleed bolt on these engines so you have to remove the expansion cap when the engine is cold and run the car to normal operating temperature to purge the system of air. Some more knowledgable person on this forum might be able to confirm this.

 

i take it you have tried switching the heater to cold and then to hot again?

[MatTdi]

Hi Latrine,

The lack of heating happened to me as well after I changed the stat, I guess you get a small air pocket and with out circulation from the pump it air locks the heater matrix.

 

Have a look at My saga

 

Hope this helps and be lucky

 

M@

[latrine]

Thanks chaps

 

I'm still confused though!

 

If the pump, stat or (heaven forbid) head gasket are knackered, why does the car heat up to 90 degrees and not byond, unless the engine is put under load? - what keeps it cooled to 90 if the not the stat or pump?

 

Also, why would it go into the garage yesterday, with the old stat in place and the heating worling fine, but come out there with a new stat but no heating?

 

hopefully, this just opints to an airlock, but again all further comments are welcomed, please!

 

cheers

[tiny]

If you had the job done in the garage take it back and tell them you suspect you have an airlock of which no heating is a pretty classic symptom(so is having not put a stat in at all!).

 

As for why the engine was only overheating under load, perhaps your stat was knackered but still giving partial flow (stuck semi open/opening so far only - or do they have a bypass) so the cooling system may have been able to cope until you put it under load.