No Cabin Heat - Got Us Puzzled

[NikpV]

Right - this is an odd problem ...

 

Once the car is up to temperature there is no heat to the cabin.

 

Christmas 2010 the water pump failed on its shaft, had that replaced (no debris). It overheated and got to about 110 before I noticed but backed off and got home with temp back on 90.

Since then cabin heat has been a bit precious. Prior to the pump being replaced it used to get up to temperature and then stay there until the engine was turned off however I drove. Now I can get it up to temperature and keep it there with 'normal' driving but in an effort to save diesel whilst commuting I will often pootle along at 55mph, at that speed the engine stays on about 80 degrees and I have cabin heat :-) after a couple of roundabouts where I have to accelerate the temperature goes up to 90 and guess what no cabin heat :-(.

 

The car does not overheat even if I push it - temp doesnt get above 90. The after run pump sounds like its still working.

If I consistently drive at 60//65 there is no loss of coolant but driving faster sometimes results in coolant loss although there is no evidence of leakage and coolant pressure test is fine. I have dusted talc around reservoir and there is no evidence of water bubbling out through pressure cap.

Had garage who did the original water pump change have a look, they have checked the thermostat and thats fine. I started wondering about the dreaded head gasket but there is no evidence of oil in water, water in the oil, over pressurising or when they did the gas over air test.

 

Starting to wonder where to look now :-) ideas gentlemen (and gregers)

[chrispb123456]

Hi Nik

I think I would be inclined to have a look at that water pump impeller just in case it's slipping on the shaft. You can feel this through the thermostat housing.

What about the rear heater is that hot and of course the booster heater is that working.

[NikpV]

Hi Nik

I think I would be inclined to have a look at that water pump impeller just in case it's slipping on the shaft. You can feel this through the thermostat housing.

What about the rear heater is that hot and of course the booster heater is that working.

 

 

thanx for the input

 

Booster heater hasnt worked for 4 years now - somewhere I have a new glowplug but as I cant see how that would affect the current situation I havent bothered to fit it, new water pump was checked when the thermostat was - If it were overheating I would still suspect it but as it isnt ............

Edited February 15, 2012 by NikpV

[zorgman]

what he means is when theres no heat from the front unit switch on the rear see iff any heat comes from there, i lean towards air lock, then again this is a strnge one ill think about it but lets know about the rear cabin heater as that will give us some clues a to whats going on

[gregers]

nik,sarky.;)

 

mmm im wondering if you need to get the booster sorted.

i know when mine didnt work any residuel heat that i managed to build up quickly

disapered rather sharpish when i turned the heater on.

does the run on pump work as it should?

Edited February 15, 2012 by gregers

[NikpV]

what he means is when theres no heat from the front unit switch on the rear see iff any heat comes from there, i lean towards air lock, then again this is a strnge one ill think about it but lets know about the rear cabin heater as that will give us some clues a to whats going on

 

get heat from both rear and front cabin heaters when not up to running temperature....when up to temp no heat from either doesnt matter what combination is on

[NikpV]

nik,sarky.;)

 

mmm im wondering if you need to get the booster sorted.

i know when mine didnt work any residuel heat that i managed to build up quickly

disapered rather sharpish when i turned the heater on.

does the run on pump work as it should?

 

provided I am running along at 55 ish the engine temp stays constant at 80 and I get heat from both from and rear heaters nice and hot (well as hot as it ever gets)

Edited February 15, 2012 by NikpV

[gregers]

what he means is when theres no heat from the front unit switch on the rear see iff any heat comes from there, i lean towards air lock, then again this is a strnge one ill think about it but lets know about the rear cabin heater as that will give us some clues a to whats going on

 

get heat from both rear and front cabin heaters when not up to running temperature....when up to temp no heat from either doesnt matter what combination is on

 

silly thought,when its gets to correct temp.could there be a split pipe somewhere thats opening up?

[NikpV]

silly thought,when its gets to correct temp.could there be a split pipe somewhere thats opening up?

 

well there is no loss of coolant if I run for any length of time at 65 but temp will be up to 90 and so no cabin heat - its only when I run for any length of time at 70+ there is sometimes loss of coolant but no evidence of where it goes - all the hoses behind engine have been replace. Coolant system has been pressure tested and I would have thought it would have detected split hoses then ?????

Edited February 15, 2012 by NikpV

[MadBaz]

Just throwing a few things at ya

Anything in VAG-COM, HVAC? Flashing c/c display?

Are rad fans kicking in at high temp?

Air lock?

Run on pump working for 3 minutes after ign off?

Rad sediment?

Leaks at booster?

When pipes replaced, were they installed correctly?

Rad pipes in good condition? ie not collapsing.

[zorgman]

had a think about this one and all this happened since water pump got changed, so i reckon its down to the pump or now im not sure here the stat is acting itself as 5mph difference seems to make the fault come on how i dont know but id deffo go for pump. water into the heaters is force fed whereas the radand engine will use convection.

[NikpV]

had a think about this one and all this happened since water pump got changed, so i reckon its down to the pump or now im not sure here the stat is acting itself as 5mph difference seems to make the fault come on how i dont know but id deffo go for pump. water into the heaters is force fed whereas the radand engine will use convection.

 

I was thinking this but It overheated quickly when the pump had gone and I cant get it to overheat now -

[Owdrider]

Hi,

 

I'm new to the forum. Been lurking a while because of some trouble with my last Galaxy that sounds exactly the same as yours.

It started off just like you describe. Had to keep putting small amounts of coolant back in after journeys. then it seemed ok around town.

Longer journeys it started to lose water rapidly and overheat. Some days it seemed ok then others an absolute nightmare.

There was no water getting into the oil, but oil was getting onto the coolant.

After trying all sorts of stuff - new pump, thermostat, etc etc....

It ended up that the cylinder head was cracked :rolleyes:

[NikpV]

Hi,

 

I'm new to the forum. Been lurking a while because of some trouble with my last Galaxy that sounds exactly the same as yours.

It started off just like you describe. Had to keep putting small amounts of coolant back in after journeys. then it seemed ok around town.

Longer journeys it started to lose water rapidly and overheat. Some days it seemed ok then others an absolute nightmare.

There was no water getting into the oil, but oil was getting onto the coolant.

After trying all sorts of stuff - new pump, thermostat, etc etc....

It ended up that the cylinder head was cracked :rolleyes:

 

yes starting to think along those sort of lines - what I was thinking that when not under load little or no gas leaking into coolant so circulation giving cabin heat but up to load enough combustion gas going in to stop the circulation and under demanding load losing water into cylinder and out of exhaust - go on boys what do you think - I can take it (I think) :-(

[chrispb123456]

Hi Nik

Did you not say you had been pressure and gas tested?

 

Do you get any excess pressure when removing cap, any sudden rise in coolant level and pumping out of coolant even with a barely warm engine.

I know I keep on about the pump but far easier to confirm.

Can you trust the garage to have checked this, it's only two bolts to remove stat housing can you not do this for peace of mind, removing head is your last resort unless it becomes obvious that there is excess pressure.

 

My way of thinking about the pump, at low engine speed if impeller was loose there would be a small amount of friction enough to shift a small amount of coolant around the system, a sudden rise in RPM could cause more slip and result in little or no circulation until RPM falls, a bit like the viscous coupling from years gone by.

[NikpV]

Hi Nik

Did you not say you had been pressure and gas tested?

 

yes both but having talked to them the gas test was done with engine 'up to temp' not under load

 

 

Do you get any excess pressure when removing cap, any sudden rise in coolant level and pumping out of coolant even with a barely warm engine.

 

no certainly not with warm/normal engine temps.

 

I know I keep on about the pump but far easier to confirm.

Can you trust the garage to have checked this, it's only two bolts to remove stat housing can you not do this for peace of mind, removing head is your last resort unless it becomes obvious that there is excess pressure.

 

I dont think they have tested the pump - I was going on the fact that I cant get it to overheat even with hard driving and the problem was evident straight after they installed the new pump

My way of thinking about the pump, at low engine speed if impeller was loose there would be a small amount of friction enough to shift a small amount of coolant around the system, a sudden rise in RPM could cause more slip and result in little or no circulation until RPM falls, a bit like the viscous coupling from years gone by.

 

Yes I can see what you are getting at here but why would there be loss of coolant when under load ?

Edited February 16, 2012 by NikpV

[chrispb123456]

Only other thing I can think of for disappearing coolant could EGR cooler, this gets extremely hot with the exhaust gas passing through, this may only show up at high temperature with any coolant being ejected through the exhaust.

[Owdrider]

Loss of coolant through expansion/overflow when under load?

When releasing the coolant cap there was a lot of pressure from ours.

Hence when running at low revs and steady driving it mostly seemed ok, but put under load the compression from the cylinders was getting through the cracks into the coolant system.

I'm no expert so can't help you too much other than let you know how ours went. It started as a little problem for us & gradually got worse.

Hope it isn't for your sake!

[NikpV]

Loss of coolant through expansion/overflow when under load?

When releasing the coolant cap there was a lot of pressure from ours.

Hence when running at low revs and steady driving it mostly seemed ok, but put under load the compression from the cylinders was getting through the cracks into the coolant system.

I'm no expert so can't help you too much other than let you know how ours went. It started as a little problem for us & gradually got worse.

Hope it isn't for your sake!

 

how much did it cost to sort ?

[Owdrider]

New cylinder head fitted cost us 1200. Edited February 18, 2012 by Owdrider

[NikpV]

New cylinder head fitted cost us 1200.

 

was that 'new' or pre-loved B) cylinder head ?

Edited February 18, 2012 by NikpV

[Owdrider]

New.

The main reason I had the car back when it got written off at Xmas! B)

[NikpV]

New.

The main reason I had the car back when it got written off at Xmas! B)

 

as yet i am not convinced what the problem is but just trying to get a feel for the worst case scenario, at what point does the repair become uneconmic?? Local garage have done a few head gaskets on these and have quote

[Owdrider]

We convinced ourselves to hang onto ours for the same reason. I knew that work had been done to the car that would last us another few years.

I ended up spending 2700 on our car in 2011 because the turbo failed AND the cylinder head cracked. (a few other things swapped too)

I could have spent the same to get a different 2nd hand car, but back to the scenario of not knowing what was wrong with it and feeling like we were starting all over again.

As it was, while I was sitting outside my sister's house with the handbrake on, some goon drove straight into me, head on, at 30mph without even braking!

Complete write off and thousands lost.

I probably wouldn't do it again! :)

I'm hoping our new (used) Galaxy doesn't develop any major problems.....

[NikpV]

Only other thing I can think of for disappearing coolant could EGR cooler, this gets extremely hot with the exhaust gas passing through, this may only show up at high temperature with any coolant being ejected through the exhaust.

how could this be diagnosed ?