From: Tim Downie on
Zimmy wrote:

> 15w/40 is only 'thicker' than 5w40 when its cold, not hot so you
> wouldn't expect it to hit your long journey mpg at least.

Well, it'll be interesting to see what happens but I've never had such poor
fuel consumtion on a long journey.

My car has had a problem recently when cold that I've only just realised has
been happening since the oil change. At steady low speed the engine has
been running roughly with a bit of "shunting" through the drive train. This
has disappeared as the engine has warmed up.

> I suspect that possibly something else has changed or maybe your old
> oil had gone really thin.

Well, I did get two new front tyres but I made sure that they were well
pumped up before my long trip. It's certainly possible that they were a
factor but I'm more inclined to blame the oil. We shall see...

Regards

Tim


From: Simon on
"Tim Downie" <timdownie2003(a)obvious.yahoo.co.uk> wrote in message
news:5ef2b2F3808msU1(a)mid.individual.net...
> Zimmy wrote:
>
> > 15w/40 is only 'thicker' than 5w40 when its cold, not hot so you
> > wouldn't expect it to hit your long journey mpg at least.
>
> Well, it'll be interesting to see what happens but I've never had such
poor
> fuel consumtion on a long journey.
>
> My car has had a problem recently when cold that I've only just realised
has
> been happening since the oil change. At steady low speed the engine has
> been running roughly with a bit of "shunting" through the drive train.
This
> has disappeared as the engine has warmed up.
>
> > I suspect that possibly something else has changed or maybe your old
> > oil had gone really thin.
>
> Well, I did get two new front tyres but I made sure that they were well
> pumped up before my long trip. It's certainly possible that they were a
> factor but I'm more inclined to blame the oil. We shall see...
>
> Regards
>
> Tim
>
>

New tyres will probably have a greater diameter than the old ones, causing
the car to think it has travelled less far than it really has on each litre
of fuel. This would only account for about a 2% difference though.


From: Chris Bartram on
Tim Downie wrote:

> My car has had a problem recently when cold that I've only just realised has
> been happening since the oil change. At steady low speed the engine has
> been running roughly with a bit of "shunting" through the drive train. This
> has disappeared as the engine has warmed up.
Have you had a fault reader on it?

If that shows nothing, I wonder of the hydraulic tappets are jacking up
with the thicker oil? I've never heard of it with the VAG TDI, but some
ford engines (Zetec?) play up like buggery with the wrong oil.

I would say flush it before changing the oil, but some say that the
fushing oil isn't good for the cam either, as it's so thin.
From: moray on

"Chris Bartram" <news(a)delete-me.piglet-net.net> wrote in message
news:NTdgi.12304$p8.7089(a)text.news.blueyonder.co.uk...
> Tim Downie wrote:
>> I took my 2.0 140 PS TDi VW to my local garage for a 20,000 mile service
>> (which is pretty basic).
>>
>> When I got it back I noticed the the fuel consumption seemed pretty high.
>> I'd recently had two new front tyres so I checked the pressure and found
>> that they were a little low. I topped them up but the fuel consumption
>> continued to be almost 5 mpg off the original consuption figures.
>>
> How does it perform?
>
>> When I checked the receipt I noticed that they'd used 15W/40 oil (which
>> was suspiciously cheap at 5:06 +VAT a litre)that they've since assured me
>> is suitable for my engine. As a "goodwill" gesture, they've agreed to
>> change the oil for the proper stuff from VW and the filter. VW dont'
>> specify a viscosity in their car manuals but the spec has to be VW 507
>> 00, VW 505 01.
>>
>
> The price isn't too cheap- GSF retail a quality PD oil for 5.70/litre, but
> the grade of the stuff you have is wrong- I *think* all the 505.01 oils
> are 5w/40 or better, and doubtless the oil doesn't meet 505.01, which is
> the minimum for PD engines. It's a bit thick, but I wouldn't expect that
> to knacker the economy, unless the hydraulic tappets are playing up?

The older spec VW long life oil was 5w/40 fully synthetic.
It's the exact same stuff as Vauxhall used to spec for their diesels on
vairable service intervals, as the drum we've got at work lists the VW 501
spec on it.

The latest VW long life spec (601.01?), comes in a drum with only that
number on it, and even at our majorly discounted bulk prices, is very
expensive.