Crap Heater

[kevinfourlegs]

Its official, the heater on mine is crap. At best the hot air can be described as tepid. Useless when the ambient temperature drops below freezing, like last night. Cleared the outside of the windows, started car and put wipers on.

After driving 15 miles, give or take, I put a bare foot at the heating duct in the driver's footwell with the heater on hot and the hot air was tepid at best. Blower was on speed 2. Turned blower to full and the tepid air seemed to be cooler?

The heater on my Diplomat was spot on. Unfortunately that had air con, but my GL doesn't.

The previous owner changed the matrix. The coolant is a 50/50 mix of Vauxhall long life coolant and boiled water, left to cool before refilling and bleeding system.

[melinx]

Silly question; is the heat control cable attached ?

[PeterC]

Like yours Kevin. my blue one was dozey. Took forever to warm up (gauge never more than one or two mm of the bottom as well). The moving air, not the heat, was the most effective part of demisting and to that end I recommend you open a rear window about 5mm to let the air flow through. The faster the fan speed then the cooler the air is more likely to be btw (law of physics). I think my thermostatic valve was knackered (the one that stops the water going round the radiator when it does not need cooling) but never got changed. Can't help thinking that is your problem also (I dont think it is an expensive part and easy/little water loss). The Rioja Carltons gauge goes up and down like a yo-yo, i.e. normal and gets up to 50% in a traffic jam (still scares me though) and the heat comes on quicker (well we will see this winter).

No-one wants a crap heater, it makes a terrible smell in the car  .

[The Duke]

What does the temp. gauge show? If it barely registers even when the engine should be warm I'd say that the thermostat is stuck open.

[kevinfourlegs]

Heater cables are attached.

Temp gauge needle always at top of blue segment. Sat in traffic idling the needle goes up to first white mark, but heater is no hotter. Once car is moving, needle goes back to top of blue segment.

[carlton_mad]

tbh kevin i would try the thermostat easy enough on the 2.0 but be careful to nip the bolts BEFORE undoing them just a tiny bit i have had a few break on me and that is fun you dont need!!

[melinx]

The temperature gauge on the Carlton is notoriously incorrect

A way of testing if the engine is getting hot enough is to remove the plug on the coolant temperature sensor (the 2 pin plug) when the engine is fully warmed up and put an Ohm meter on the sensors 2 pins.

It should read around 200 to 250 Ohms; if it reads significantly higher, the thermostat is probably jammed open and the engine is not reaching the specified 92 degrees C.

[kevinfourlegs]

Thanks for the advice guys.  Should a bolt snap, I do have a spare housing, which came off my Diplomat.

[Pedro]

.............the thermostat is probably jammed open and the engine is not reaching the specified 92 degrees C.

When mine was a 2 litre, I had to fit a new thermostat every winter.  The 2.0 litre 8V engines seem notorious for this problem, as some Calibras, Cavaliers and Astras were the same.
 
Sorted that in mine though......................stuffed a 24V 3.0 litre in the engine bay!!

[Johnny A]

just to throw another variable into the mix, my 2.0 estate had exactly the same heater as yours - lame. I blamed it on a blocked matrix so bought a replacement.

I didn't get round to fitting the new matrix before I fitted the 3.0 24v lump..... which cured the problem.

I can only guess that the 2.0 had a blocked hose to or from the matrix or something similar (lame water pump?)

[chris]

My first GSI had exactly the same symptoms, thermostat was stuck open.

[kevinfourlegs]

Done a few miles today and I thought, hmmm, I wonder.

Whilst sat at the traffic lights, I put the heater on hot. I then put the blower on speed 2. The vents at the end of the dash were open, as always. The top air distribution lever, Vauxhall's words, not mine, was set to windscreen, while the bottom air distribution lever was set to face vents. Hot air came through passenger side windscreen vent and the vent in the end of the dash. However, on the driver's side, hot air only came through the end vent in the dash. The windscreen vent only had cool, tepid air, at best.

Leaving the top air distribution lever set to windscreen and the bottom one set to foot wells, the passenger side gets warmer air in the footwell than the driver side.

Under the bonnet, both the top and bottom hoses are hot. The top of the radiator is extremely hot. The bottom of the radiator is cooler.

[Catho]

Sounds like similar symptoms of an airlock.

Had one on my Beemer, (notorious on the 520i apparently) after I fitted a new rad earlier this year.

Cold air in cabin, red hot pipes/hoses on one side at top but stone cold at bottom, cold pipes at back of engine going into bulkhead.

Took me hours to get rid of it, massaged rad hoses, released bleed valves on pipes/hoses, even jacked up front of car to get water flowing rearwards (as advised by a mechanic), then.....eureka!!! temp gauge dropped back to where it should be and HOT air in cabin. 

Not sure if it's the same problem as what you've got Kev, but may be worth looking into.

[kevinfourlegs]

I know BMWs can be notoriously difficult to bleed. I've done a couple, one of which was my 7 series. A hose split and the only place I could get one was from BMW at a cost of £140. When I started to bleed the cooling system, there was 1/4 tank of unleaded. By the time I got all the air out, the fuel warning light was on.

After hijacking my own thread, back on topic.

I will have a look at bleeding the cooling system.

How come there is hot air on the passenger side windscreen vent and cooler air from the driver side windscreen vent? Has a pipe come off?

[PeterC]

tbh kevin i would try the thermostat easy enough on the 2.0 but be careful to nip the bolts BEFORE undoing them just a tiny bit i have had a few break on me and that is fun you dont need!!

Question Chris - I don't think I know what "nip" means. I thought I did but I cannot be right. Can you explain as I might wish I knew one day !.

[kevinfourlegs]

I think he may mean to tighten them slightly, before loosening them? Then work the bolt back and forth, before removing the bolts. They are prone to shearing.

[Murph]

Spot on Kev.

[kevinfourlegs]

I'm learning. Another couple of years and I should be an anorak on Carltons 

[PeterC]

I think he may mean to tighten them slightly, before loosening them? Then work the bolt back and forth, before removing the bolts. They are prone to shearing.

Thanks Kev, makes sense. Always thought nip meant tighten up correctly so now you say that I realise I was being a bit stupid. I have coped with damaged threads by going backwards and forwards (effectively cutting a new thread). Never really thought of turning the wrong way first before loosening !.

I have tapped a bolt on the head before just to stir up the thread, never been totally sure I was achieving anything. Worst thread I had was cylinder studs on an MZ motorbike when I was a young lad. All of them were a bit stripped so undid rather lamely - dont know why the thing ran. I undid them carefully so the nuts found the remaining thread and put longer nuts on top of a few washers. Worked !. I was always the one given a "wonky" spark plug to deal with in those days !. I have ruined a few threads myself but on nuts & bolts so easy to replace - bit lucky. I bent a wheel brace trying to undo a wheel bolt on the Blue Carlton ! so nowadays I prefer to tighten up replacement wheels/tyres my self. I notice my Rioja Carlton has copper slip on the wheel bolts is that worth/relevent using on lesser things like the thermostat etc.

[melinx]

I notice my Rioja Carlton has copper slip on the wheel bolts is that worth/relevent using on lesser things like the thermostat etc.

I always use a smear of Comma anti seize compound on any bolts including wheel bolts and also smear the mating faces of alloy wheels with it

[kevinfourlegs]

I was going to have a look at why the driver's windscreen vent does tepid air, while the passenger side has warmer air. That will explain why the winscreen on the passenger side demists faster than the driver's side.

[man of kent]

I was going to have a look at why the driver's windscreen vent does tepid air, while the passenger side has warmer air. That will explain why the winscreen on the passenger side demists faster than the driver's side.

If you park under a tree the plenum chamber can get blocked with leaves.

An old trick years ago when selling an overheating engine was to take the thermostat out.

Aside from the heating issue dont let the small plastic grilles over the holes at the outer ends of the plenum get blocked as water can then run along and through the wiring holes in the dash panel. If muck gets down these holes it can block the lower drain tubes. The tubes are not continuous to the bottom and out. An upper drain tube sits into a small funnel on the top of the lower tube and this can get blocked with water getting inside onto the carpet.

Dont park under trees in autumn! This problem occurs on most cars including the 2005 vectra I had.

[kevinfourlegs]

I never park under trees. The plastic grilles are checked every week for debris.

I have heard that trick of removing the thermostat. On the 2.0 lumps, the thermostat is part of the housing, that the top hose fits on to.