Doug, we share the same opinions.

Regarding your post further up, I have a comparission... Unfortunately not in paperform. Amd thismdoesn't deal with a Jaguar but...

In my C30 times, I had my car serviced to its best. It would neber run for less than 7 km (below that Imwould either walk/cycle or resist the need tomdrive). My C30 had in the end 207k km on the clock as I sold it... Before it sold, it got a major service... That included new plugs, a compression test and a cylinder inspection.

Compression was an even 14.1 bar/cylinder. No oil use. Inside the engine the oil wa golden - even after 20k km. Everything spot on.

A friend bought a short distance city driven C30 with the same engine from an older man who would let it idle around 10 minutes before driving off. It had 60k km on the clock and full service history from the same dealership as I was using. It was barely younger than mine - let it be 6 months. After him having to teach the car to drive faster than 70 kph, he noticed a bad fuel economy... Something like 16l/100 km opposed to my 6.5l/100 km (145 hp, 2.0l non turbo 4 cylinder petrol). He took it to the same shop that did mine for a large service... Result:

Uneven compression between 8 and 11 bar (far too low!) - should have been max 1 bar difference between the cylinders. The cylinder walls were blank (no signs of machining!) and the valves were coked up.

He learned: don't buy ****!

 

1. start the car

2. turn on seat warmer

3. return to car once seats have warmed up

4. drive gently till temp hits N

5. utilize kick down to clear out carbon deposits

 

Yes, but ...

a) who wrote the article

b) what was the basis of the proclamation

c) and in the age of the internet, how many times has it been
plagiarised without any form of fact checking whatsoever?

 

BTW, for those accustomed to watching a real oil pressure gauge,
you might remember how scary the oil pressure can be after startup.

As in pegged to the max pin.

That's a sign that maybe the engine isn't quite ready to boogie.

 

Hi OB,

Good to hear from you again! I'd like to add my ignorance to the pool...

I've always been led to believe:

- 90% of the wear on an engine happens in the first 30 seconds of starting from cold

- Unncessary idling from cold causes fuel wash down the cylinder bores because even FI engines are "over-fuelled" and under-aired" at cold idle


I've always assumed, therefore, that it's better to start the car, let the oil pressure build up and fast idle stabilise, and then start driving as soon as possible after that. Don't exceed 2k for a few minutes but by driving at varying engine speeds, it increases the air input and helps to better optimise the fuel / air ratio and also warm up the engine quicker which will then bring down the idle fuel ratio.

Ideally, we would never start an engine up from cold, hence my forthcoming project to install a genuine coolant pre-heater on my AJ16 XJS. However, I'm still struggling to get any pics from someone who's got one fitted in their AJ16 XJS (it has a strange bottom hose arrangement).

Cheers

Paul

 

About 25 years ago, when I was in the trucking business, the company I was with had some engineers from Caterpillar, or Cummins? in to give us a talk about how to drive their engines for best efficiency. They pretty much said just get in and drive, don't warm up, is the way to get the most $$ return. As I remember basically the fuel cost to warm up would cost way more than accelerated wear, if any. I don't remember if they said that it would or wouldn't cause more wear, probably didn't say since their focus was on cost/efficiency. Also a huge diesel I'm sure is somewhat different than our cars. Anyhow if your goal is purely financial maximization that's probably the way to go.

I think there's also a big difference depending on how cold it is - I don't drive the Jag in winter here so not much of an issue for me, but my winter car sure acts different when it's -10F rather than 35, I let it idle a bit more when it's really cold, at least till the rpms start dropping, and then drive as gently as I can till it starts warming up (gauge rising). I do drive the Jag gently also till it's warming, it just never starts from that really cold temp.

Just my opinions though, anyone can do as they please with their car!

 

Hi Doug

This is about how long guys leave their Cars to warm up.

Some guys just start up and go, while others will leave the engine to warm up for a while.

While the Article I was reading was giving advice on how it should be done.

Which may or may not apply to an XJS, as I once stalled mine in the road when the AAV started hunting and the engine just shut down.

 

Hi Flint

I can't see anything wrong with doing it that way.

 

It was on one of those News Feed 'Thingys'

So how accurate it is I wouldn't know.

 

Got to agree with you there Plums.

Waiting for that Barrel gauge, can be nerve jangling stuff.

 

I'll let you know how close you are to what the Article said

 

Another thing is if you lay your Car up for the Winter (like not use her for six months or so) the Oil may start running off some of the moving parts.

So would it be better not to Start her at all for (six months) or Start her every couple of weeks just to keep her fresh and the Oil moving.

In which case if you can't take her out on the road for any reason ie (not Taxed) if you didn't let her properly warm up, then there is a possibility that the fuel injection system, may interfere with her Starting again later on.

Which is a problem that someone on here advised me of.

So all in all a little bit of a 'Catch 22' situation, unless someone wants to chuck in their 2 cents?

 

First 10 seconds, I have to agree with you on that one Doug, however I was looking at it from an oil temperature/viscosity point of view, oil delivery on start-up is another story, and certainly where the most initial wear would occur.

 

Every vehicle / engine is different. Some of them you can wake em up, slap em in the face and take off. Other engines are cold blooded and just have to be warmed up. My bike (big single) even with it's fuel injection has to warm up for 3 or 4 minutes or it dies at the first stop. My XJS V12 warms up for 30 secs, drive off and runs great. You live with them and learn what they need.
...Jimmy

 

I'm with Jimmy.

Mine are ususally 1, maybe 2 minutes TOPS.

The V12's without an AAV, and 25ltrs of coolant, about 2 minutes in winter, our winter, not what some of you have, mind you.

The X300, basically until the idle drops to 750ish, which is the stepper motor doing what it does based on temps. Maybe 30+ seconds.

The S TYpes, same as the X300, basically when the idle settles to below 900, time to go. About 30 seconds I suppose, never timed it.

The MK10, well, language barriers prevent the truth here. Basically, once it decides that I am goinng to WIN, and you are going to start, I drive the pants of it before the Prince of Darkness drops by and ruins things again.

 

Is this some "top secret" you just don't want to share the info article??? smh.

 

Our type of driving I think is ideal for engine longevity, we live in the country and the roads near our house start our commute to work at 25 to 45 mph for the first 10 minutes (no warmup idling), then 60 mph for a 30 minutes. Never had an issue with bearing wear, lack of compression, or oil consumption on any BMW, Chevrolet, or Ford even up to 300,000 miles which has been our upper limit on keeping a car. I believe the very most important factor is getting the oil temp up over 100C for an extended time period to ensure that the internal condensation boils off and is purged through the PCV system.


Those who have motorcycles may be familiar with "cold seizure" where when too much load (WOT) is placed on the engine, the piston expands faster than the cylinder wall and seizes on the bore causing damage to piston, rings and cylinder. In theory seems like auto engines (although less of a factor with iron blocks and iron liners) should have the same potential issue and a good reason to warm up to normal operating prior to applying heavy throttle foot. Seems like common sense too.


Of course cold country folks using remote start to warm up the car while they are inside making coffee open up a whole other category don't they ?

 

According to the Article I was reading, it suggested that the best way of minimizing wear would be to start driving the Car as soon as possible.

Which seems to be what some of us have been doing.

And so just out of interest, I wondered if they gave any advice on this in my Owners Handbook for a Jaguar XJS V12.

And this is what it says on Page 103 Running and Safety.

Warming Up

Do not operate the engine at high rev/min when first started but
allow time for the engine to warm up and the oil to circulate.

A thermostat is incorporated in the cooling system to assist rapid
warming up.

In very cold weather it is advisable to run the engine at 1500 rev/min with the vehicle stationary until a rise in temperature is indicated on the gauge.

Where having read that I was wondering, if maybe some of us had been doing it wrong?

If anyone has a manual for the 6cyl model, it would be interesting to see if the same thing applies and its probably on the same page as the V12 Owners Handbook, page 103.

 

Again we're faced with the definition of 'warm up'




Here, at least, the driver is given something specific to look for: movement of the temp gauge needle.

I disagree with the advice, but that's another story




This may well be a case where right method versus wrong method ...even if we all agreed on which was right or wrong....is of no real world consequence.

What we're talking about is which method reduces engine wear, right? We'd have to take two (or, ideally, several) new engines which, except for 'warm up' method, have been ** operated and serviced identically over their lifetime **. Then at (let's say) 200k miles, tear each engine down for a detailed examination and measurement of all wearing items.

Anyone raising their hands to volunteer ?

In the real world, warm up method is just one of many small factors that combine with others ....or perhaps be overshadowed by others....that contribute to engine wear.

Cheers
DD

 

Hi its no Top Secret

But I was interested in comparing the various ways that XJS drivers, warm up their engines or not as the case may be.

Before they go and take them out on the road, so I guess its all down to a question of keeping the revs to a minimum and having a feel about what is best for your Car.