I've recently heard that diesel engines do not warm up at idle and you need to drive away instantly to warm the engine up. As my 1.4 tdi 80 2 estate is on order I was wondering how diesel owners de-frosted their cars in winter in the past, or how they plan to in the next winter??? As I have no garage and leave for work at 5.25 am, I am a bit concerned!!!

Edited 21 July, 200817 yr by jaxx007

If you idle your car for about 10 minutes. There is sufficient heat generated by the engine for the heater to work. Even below freezing it still works.

Or buy a car cover for it.

If you idle your car for about 10 minutes. There is sufficient heat generated by the engine for the heater to work. Even below freezing it still works.

Or buy a car cover for it.

No No No No No!!!!

Idling a derv does not warm it up any significant amount and you will cause massively increased engine wear.

Get in the car and drive straight away to get some heat in, use an electric fan heater inside the car for 10 minutes to defrost it or go and get one of these fitted for instant heat:

Webasto England

An added advantage is that they heat the whole engine so reduce engine wear from cold and while they use a small amount of fuel to run, they save more than that as the engine is never running cold.

Well if idling causes engine wear quicker, would sitting still on a freezing morning with the revs at say 1200-1500 rpm warm the engine up quicker and not cause as much damage because the engine will be warming up? Would this decrease engine wear compared to idling and warm the engine and the heater up quicker? I know I could keep de-icing the windows with de-icer and wiping the inside of the windows with a cloth but they would become streaky.

Well if idling causes engine wear quicker, would sitting still on a freezing morning with the revs at say 1200-1500 rpm warm the engine up quicker and not cause as much damage because the engine will be warming up? Would this decrease engine wear compared to idling and warm the engine and the heater up quicker? I know I could keep de-icing the windows with de-icer and wiping the inside of the windows with a cloth but they would become streaky.

It really is best to drive off ASAP. I keep kitchen roll in the car to wipe the inside with, amd use de-icer outside. Even the raised idle won't generate a lot of heat, the engine needs some load.

The wear on key components is highest at idle so if they are poorly lubricated and under maximum load they will break quicker.

I'd get the engine warm by driving it to just before the turbo cuts in for a few miles and then maybe let the turbo in slowly to get some heat in.

You can leave a derv to idle for 20 minutes and it won't be up to full temp.

I appreciate that the engine will not be at full temperature. As I know diesels are thermally efficient. But you dont need it at full temperature for the heater to work to clear the screen. Any engine may wear when idling from cold and I have done that with mine and never had any problems with the car during icy winters in nearly 3 years.

My usual process when the car is outside.

Get, in and start engine,

Clear ice from external glass, using either de-icer or scraper,

Switch on rear screen demister,

Drive off.

The short time the engine is running before I drive off is usually enough to stop the windows misting as soon as I get in.

And mine, not quite the same:-

Get, in and start engine,

Switch on rear screen demister,

Clear ice from external glass, using either de-icer and/or scraper,

Drive off.

to cheezemonkhai, you say to warm it up by driving it to just before the turbo kicks in! Do you know what revs that is. I had a test drive but I was concentrating so hard on the road and using my ears for road noise etc that I didn't notice the revs too much. The one time I did look I was 1800 rpm and the turbo was definately spinning cos the surge was instant. P.s I drove the tdi 80 in a roomster, not a fabia cos no fab's with this engine were available but the surge was definately there. Does anyone know the revs when the turbo starts to spool up??? Please forgive me if I sound stupid but I've never owned a turbo diesel before!

I think it's about 1500, and I have to have the music off and driver's window open to hear it at all (Elegance trim).

the turbo just coming in won't be doing any harm and will warm it up a bit quicker, it is just that you don't want to be giving the turbo a hard time when cold as the oil acts as it's bearings and so when cold the wear on the turbo may be greater.

okey dokey, thank you for that. Until the engine is warm I'll be sure to keep it under 15-1600 revs. When it's warm I'll use the turbo as required. They say when running the engine in to take the revs to 2500 quite often, but I know now to warm the engine up before doing that. I've never owned a new car before so I am ever so grateful for all your advice!

Thank you again

You don't have to be that accurate just start it and move straight off and don't drive it hard or labour the engine. Taking it to 2.5k revs won't harm it when it's cold, but just don't try taking it anywhere near the redline as you will be asking for reliability problems in the long run.

Last winter some moron in our neigbourhood had some V6 Rover thing which he left idling to warm up of a morning. I was sorely tempted to stuff a potato up his exhaust as it was rather annoying when I was trying to drop off to sleep after a night shift. Yes, his exhaust, not the cars!

I always defrost screen etc. using other means, then start the engine and get going straight away taking it a bit easy until the temp gauge is indicating around normal.

Unfortunately Jaxx007 car won't have a temp gauge but I presume the aircon will clear the inside of mist.

to cheezemonkhai, you say to warm it up by driving it to just before the turbo kicks in! Do you know what revs that is. I had a test drive but I was concentrating so hard on the road and using my ears for road noise etc that I didn't notice the revs too much. The one time I did look I was 1800 rpm and the turbo was definately spinning cos the surge was instant. P.s I drove the tdi 80 in a roomster, not a fabia cos no fab's with this engine were available but the surge was definately there. Does anyone know the revs when the turbo starts to spool up??? Please forgive me if I sound stupid but I've never owned a turbo diesel before!

The turbo is rotating from idle, it will spin faster as soon as the exhaust gas speeds up, that's half the reason for not thrashing it until it's warmed up enough and IIRC the point at which the turbo will start to 'boost' is 1800rpm.

You can hear it whistling from idle if you listen carefully.

I usually start mine, get out and scrape off the screen and then off!!! bbbrrrmmm!

okey dokey, thank you for that. Until the engine is warm I'll be sure to keep it under 15-1600 revs. When it's warm I'll use the turbo as required. They say when running the engine in to take the revs to 2500 quite often, but I know now to warm the engine up before doing that. I've never owned a new car before so I am ever so grateful for all your advice!

Thank you again

1500rpm, you won't barely get anywhere....

Look, providing you don't thrash it from cold there is no reason to stay below 2000rpm, just drive it sensible, I always have and mine is fine after 70,000 miles.

I would be pretty sure VW did some testing on these engines when they designed them to withstand more than a normal persons driving.

Edited 21 July, 200817 yr by DGW
Quote fixed

Hi Jaxx,

Although I haven't been through winter with our new Fabia Estate yet...I don't anticipate any problems with de-icing. I've had diesels previously and it's true they don't really warm up at tickover very quickly. However, some de-icer and a soft scraper will do the trick. I leave for work at just after 6am so I'm used to this routine! I don't normally start up until just before I'm ready to drive. With the diesel vehicles I've had in the past...there really hasn't been much point...it just causes wear and tear on the engine, idling it at cold.

I will say this though, this Fabia's 1422cc diesel warms up faster than any diesel I've ever owned. It chucks out the heat after just 500 yards drive down the road...at least it did today in this warmer summer weather we are currently experiencing. I wouldn't be worried!

Edited 21 July, 200817 yr by Estate Man

I've recently heard that diesel engines do not warm up at idle and you need to drive away instantly to warm the engine up. As my 1.4 tdi 80 2 estate is on order I was wondering how diesel owners de-frosted their cars in winter in the past, or how they plan to in the next winter??? As I have no garage and leave for work at 5.25 am, I am a bit concerned!!!

SWMBO has a Fabia Estate which is plugged in at night in the winter months and is warm as toast from the word go !

A quick question to a statement above. Conshine stated that the "boost" starts at 1800rpm. If that is the case, why does the tdi 70 have a flat power band between 1600-2800 rpm. Wouldn't that mean the turbo is spinning at the same rate between those revs and hence the "boost" comes in at 1600 rpm. Wouldn't that be the same for the tdi 80 in that at 1600 rpm the tdi 80 would be producing at least as much "boost" as the 70 is at 1600-2800. Or have I got that totally wrong. If so why does the turbo spool up later???

P.S. I'm sorry if that sounded long winded!!!

I can't explain it in detail, but there's a lot more than just on/off happening in turbo boost.

Similarly, there's more than just intake air to consider in determining a car's torque and hence power output at given speed.

About 18 months ago I had a 1.4 petrol and a 2.2 turbo diesel which were both garaged. It was mid winter and the garage was 5 deg C. Both cars had not been used for a week or so and I wanted to turn over the air con and thoroughly warm up the engines. Having no need at that time to drive them plus they were spotlessly clean and the roads were filthy from gritting, I decided to warm them up in the garage. After opening the garage door I carefully warmed them up one at a time. As the engine temperature rose so I increased and varied the revs. I let the cooling fan kick in three times on each vehicle and this took 28mins. with the petrol and 45 mins with the diesel!

Although the results would probably be much closer in summer weather, it illustrates how much longer it takes a diesel to warm up during cold weather. With an average speed of 25mph that diesel would have covered the best part of 20 miles.

Must get out more!

For comparison, it takes under 10 minuts for a TDi to warm up when driven with engine revs typically in the range 1200 to 2500.

A quick question to a statement above. Conshine stated that the "boost" starts at 1800rpm. If that is the case, why does the tdi 70 have a flat power band between 1600-2800 rpm. Wouldn't that mean the turbo is spinning at the same rate between those revs and hence the "boost" comes in at 1600 rpm. Wouldn't that be the same for the tdi 80 in that at 1600 rpm the tdi 80 would be producing at least as much "boost" as the 70 is at 1600-2800. Or have I got that totally wrong. If so why does the turbo spool up later???

P.S. I'm sorry if that sounded long winded!!!

IIRC from the college days, the 'boost' is the point where the pressure in the manifold generated by the turbo exceeds the nominal atmospheric pressure (14.5psi ish).

If you have a VNT turbo, it can alter the point where the turbo will spin up as it tries to remove the turbo lag.

The turbo typically spins faster the more the engine revs and we are talking anywhere between 50,000 to 150,000RPM (hence the whistle), but I think if you have a VNT, it will back the gas speed off to stop the overspin, (like a wastegate).

It won't just hold one speed over the range as this will impede the passage of the exhaust gasses.

Not sure about the different engine power bands but I would have though that the boost point could change with a different size turbo etc, not sure here, would need to do some research.