engine warm up

You surprise me. I see your point that 70-80% engine wear occurs in first 5-10mins, but does that depends on how the car is driven? Obviously if you jump in the car and drive it about to the red line in every gear from cold it will eventually kill the engine. But if you drive it gently (not putting it under load) surely the car will warm up quicker causing less damage?

 

This is not a flipant answer Will but why do you think it warms up quicker when you drive it?

Because you are making it work under load, which generates more heat.

 

thanks guys! so i take it that it is ok for me to leave it at idle on freezing mornings!

Rampz

 

Yes mate

 

I spoke to a Shell engineer about this when i was studying mechanical engineering and also a few of my lectures about this.

Golden im afraid youve got it very wrong for a few reasons mate.

The engine takes alot longer to warm up than when driving in normal conditions, bascialy meaning that the engine is running alot longer than it should be with the oil being thicker and colder in it and the circulation is obviously poorer This resultes in the top of the engine taking alot longer to get the right oil viscosity resulting in Cam wear and also tappetts etc.

The engine also gets coked up as it has to run for alot longer on cold start with it dumping more fuel into the engine causing carbon deposits all inside the head + valves etc.

Never cain the car when its cold but dont let it idle there for 10 minutes before you set off.

I learnt the Hard way as i used let my valver idle all the time for 15 minutes every morning before i would go to work and after awhile it shagged the tappets- this is what led me to ask the question

 

yeah, i do understand that!

 

Define normal conditions? I believed we all are talking about the coldest part of the British winter. I hardly think an engine bay experiencing sub-zero wind-chill temperatures is going to aid warm up.

Did this engineer retire in the 1940s? We use this wonderful stuff called multi-grade oil which maintains its viscosity over a very wide temperature range.

This is entirely dependant on the journey taken after warm up. A 5min drive then switching off will cause far more carbon build up than 5mins idle followed by the same drive.

I used to work for VAG and have never seen any correlation between idle/warm up cycles and tappet wear.

 

And to add, tappets don't wear very quickly, they just get filled with crap

 

Gents, what you need is a Kenlowe Hotstart. It pre-heats the engine and my one turns the interior fan on when the coolant gets to a certain temp, so the car is warm inside too. Excellent on cold mornings!

 

ok guys, how able letting the engine idle for a while after a long journey before switching it off?

Thanks

Rampz

 

Depends how you've just driven it, if you've coasted home at 30mph just switch it off. If you've just thrashed the hell out of it then it's a good idea.

Turbo cars should always be left to idle for a minute or two before switch off, always!

 

Golden do actually know what your talking about?

Do you understand what mulitgrade oil is?

Multi grade is able to retain its viscosity at very high engine tempretures (130C+) without breaking down- it is however thicker when cold hence does not flow round the engine quicker?

Do you know better than Vw or something who spent millions and milions of pounds developing their engines?
For them to tell you to drive the car straight away for the some of the reasons i have explianed. ANd you advise to do the opposite?

Do you know better than a Shell engineer who is paid in the reaion of 180k a year fo what he know about oil?

When you used to work for Vag was it in the parts department by any chance?



Edited by: GRINGOG60

 

You lazy muppet, if you bothered to read the whole thread you'd have seen this,

You're very rude considering you are the incorrect one,

Did your Shell Engineer tell you that?

How's this for an explanation.

"What is a multigrade oil?

Lubricants that are able to maintain their performance in high and low temperatures are called multigrade. They are defined by two numbers. The first (followed by a W) indicates the lubricants viscosity under lower temperatures. The second and higher number indicates the lubricants viscosity under greater temperatures. A multigrade lubricant minimises viscosity differences under temperature variations."

Guess where I got that from,

The Shell web site you 'tard
Edited by: Golden

 

Some reading for you gringo.

 

Owned Mother Fucker!



Fordo!

 

I don't mean to chuck a big cat amongst a bunch of tasty pigeons, but this is also from the shell website.

Read the first tip on this page.

Discuss.

 

Fight, Fight!

I would have thought that it's better to let the engine achieve a decent working temperature before moving off, as the oil is in a better state to protect the engine when it becomes loaded.

I think the reason VW don't recommend it is because it uses more fuel and takes longer.

Like everyone else I usually let it idle when freezing until the screen's cleared, then drive off - not using more than 3k rpm until the oil temp's around 70-80 degrees..

 

So basically, the question comes down to:

Which causes more wear:-

A long warm up period with minimal load

OR

A shorter warm up period with some load

Obviously the former will use more fuel..

 

Ring side seats anyone?

 

very amusing thread ......... I always make sure that the MFA shows a decent engine temp as what VW recommended ,......... surely thats the simple answer to this question ......... ??????? or am i missing something ?????