Hi guys,

My daily commute is about 9 miles, over semi-urban roads (30-40mph limits, although you'd be lucky to be actually doing that for most of it! ). Normally, it takes a little while for the engine to warm up - about 10 mins/3m for the needle to no longer be touching the thick line at the bottom of the coolant temperature gauge scale, and 20 mins/5m to get to the "upright" position (I think that's 90C? My Fabia's pre-facelift, so it's not labelled). This seemed like a long time to me, but my parents PD140 Octavia takes exactly the same amount of time to warm up fully, so I guess it's right (their route is the same as mine until the point at which it's warmed up! ).

Now that the cold weather is upon us (it was -3C when I parked up at work today!), I want to use the AC/heater to warm the interior, but I know if I do this, it will sap heat from the engine (I can see the needle fall to the left). As I know driving around on a cold engine isn't particularly kind it, I was wondering if there was anything that could be done to get the engine up to temperature more quickly? My parents did suggest doing what they did with their old cars - obstructing the air-flow over part of the radiator with a sheet of cardboard - whilst doing short journeys, although I'm not sure if that's a good idea with mine? (I know cars have got lots more electronics in them now, and don't know if it'll have a side-effect)

Any thoughts?

Thanks

Assuming the water thermostat works by restricting the flow until the engine needs cooling, then blanking off part of the radiator isn't going to work, is it? Perhaps the thermostat is stuck open?

..

Edited 23 October, 201015 yr by Lewwy

But I remember in my VW manual that it recommended that you do not use the AC system below a temperature of 5 deg C,

Well I've read the manual and it's somewhat different:

It is important for your safety and for your driving comfort that the air conditioning system is operating properly.

The air conditioning system operates when switch [⇒ page 77, fig. 87] is pressed and the following conditions are met:

• engine running,

• outside temperature above +5 °C,

• blower switch switched on (positions 1 to 4).

So it's not that you shouldn't use the AC below 5 degC, it's that it won't even switch on below that temperature.

However I don't think that's relevant to this enquiry...

Assuming the water thermostat works by restricting the flow until the engine needs cooling, then blanking off part of the radiator isn't going to work, is it? Perhaps the thermostat is stuck open?

I dunno, that's why I asked here. All I know is it's what they've done in the past to make their other cars warm up quicker. Given that their current car takes exactly the same amount of time to warm up as mine, I assumed there wasn't a fault..?

But I remember in my VW manual that it recommended that you do not use the AC system below a temperature of 5 deg C, does anyone else know anything about this? Is it the same on the Fabia? :wonder:

From my recollection, the AC part of the system switches off at low temperatures (somewhere in the 0-5C region), so you'd get normal heater only ...

Edited 22 October, 201015 yr by martinch

The warm up time is quite normal. The reason is that a diesel engine is so thermally efficient compared to a petrol.

If you use the heater, then you will slow the warm-up process. The a/c compressor doesn't operate below 5 degC but that doesn't affect the heater.

You are of course looking at coolant temperature. The oil temperature will probably take even longer to heat up.

The Mk4 golfs, leons etc with climate i believe have a bank of 3 glow plugs in a water housing leading to the water matrix to warm up the cold water coming to the heater.

I had thought about ordering all the necessary parts to "retro fit" this to the fabia to at least get the air in the cabin warm.. Always have a pair of gloves in the car these days as it seems to be my hands that get cold the most..

Kev

Given that their current car takes exactly the same amount of time to warm up as mine, I assumed there wasn't a fault..?

Sorry - I thin I misread your posting originally - but I still don't see why blanking off the radiator would make it much quicker...

Sorry - I thin I misread your posting originally - but I still don't see why blanking off the radiator would make it much quicker...

Blanking off the radiator will make no difference, as the radiator is not in the cooling circuit until the thermostat opens. That's the function of the thermostat.

Thanks, guys ... I'll ignore the suggestion, then (one less thing to do! ). Sorry if it was a dumb question, but I'm new to cars, so would rather check before I did anything stupid.

The warm up time is quite normal. The reason is that a diesel engine is so thermally efficient compared to a petrol.

Yeah, given how my parents' Octavia behaves, I assumed it was right. Their old petrol Vauxhall used to be fully warm by the time the needle is just starting to move off "minimum" on the diesels, so just a surprising difference...

If you use the heater, then you will slow the warm-up process.

That was basically the point I was concerned about - running on a cold(ish) engine. I know the manual says don't do it for very long (3m? Although that may be more for petrols, as it's obviously a combined manual), and seeing the needle move backwards was a little ... worrying (I did run in to work once in the past with the heater on permanently, and it didn't go above the 1/4 marking).

I had thought about ordering all the necessary parts to "retro fit" this to the fabia to at least get the air in the cabin warm.. Always have a pair of gloves in the car these days as it seems to be my hands that get cold the most..

Could be an interesting idea. Have been wearing the gloves too, recently (then again, it's a 1.3m walk from where I park to the office, so I kinda need them!)

Sorry - I thin I misread your posting originally - but I still don't see why blanking off the radiator would make it much quicker...

No worries, we all do it from time-to-time. The idea was suggested by my parents (I'd made a passing comment), who'd done it in the distant past (think 30 years ago). Obviously, this was a much older vehicle, so may well have been missing a lot of the "clever" stuff that's now part of our vehicles, and probably had an inferior design ... which is why I thought I'd ask.

I'd have to say my commute is only 5.1 miles and I have the heater knob permanently set to 18degC so air's coming out asap

Oh! I have been using my a/c every morning this week, It warmed the car interior up quicker, I only had it on for about 5 mins at the most then the heaters full blast, When its really nasty weather i.e Frosty/ snowing I start the car up on the drive and go back in the house until its defrosted (I can see the car from the house I never take my eyes off it!) 1st winter for me in the fabia hope it handles as well as my Micra

Depends on how far you want to go to reduce it I guess, but these things are always an option;

http://www.kenlowe.com/pre-heaters/cars/index.html

Well I've read the manual and it's somewhat different:

It is important for your safety and for your driving comfort that the air conditioning system is operating properly.

The air conditioning system operates when switch [⇒ page 77, fig. 87] is pressed and the following conditions are met:

• engine running,

• outside temperature above +5 °C,

• blower switch switched on (positions 1 to 4).

So it's not that you shouldn't use the AC below 5 degC, it's that it won't even switch on below that temperature.

However I don't think that's relevant to this enquiry...

As I stated in my post what I had read was in my VW manual and not the Skoda one!

As for it being 'relevant' the OP stated about switching on his AC & Heater to warm up his car, (stating -3deg C temps) so I was just asking the question about it being safe to run AC at these low temps, and if it will even work. So i think it was a fair question.

Lewwy

As previously described, the thermostat won't be open when the engine is cold so you can't change the warm up time by physical means with messing with the radiator. One option at the expense of fuel economy is to drive in a lower gear and therefore higher rpm. Having the cabin heater turned to warm/hot also saps heat from the engine and leads to a longer warm up time. I'd say you are correct that a lot of cold/short journeys won't do the car a lot of good in the long run as the engine oil doesn't get up to temperature and water and other products of combustion can condense in it. Therefore I'd suggest going on longer runs on a regular basis to get everything fully up to temperature and evaporate off stuff from the oil. Otherwise get an inefficient petrol!

As I stated in my post what I had read was in my VW manual and not the Skoda one!

Precisely!!!!

I thought ac only worked to cool the car I had no idea it heated it up quicker lol doh

If you think that's a long time - try a 1.4 TDI! Can take 9 miles in very cold weather to warm up. Bought a stick on sump heater (Canadian) for about £50 winter before last. Plugs into 240V. Using a timer on the socket to give a 2 hour warming period made a reasonable difference when car parked outside in snow. Easy to fit and no problems in use.

Martinch,

Don't get silly about this.

I know of seven Octy Mk.1 1.9 TDIs, all bought on the same day in early 1999. All of them have done a little over 100k miles - mainly in 11mile each way commutes. None have had any problems. Turn the heater to max and don't worry.

Where does this kind of thing end - driving without your lights on to avoid wearing out the bulbs?