Oil and fuel economy

Kowalski · Post by **Kowalski** » 28 Oct 2003, 22:44

Does the engine oil that you use make a measureable difference to anybody's fuel economy?
I've been using 15-40 diesel engine oil in my Xantae (if that is the plural of Xantia) so far and was wondering whether changing to a more expensive synthetic 5-40 diesel oil would make any difference at all.
Has anybody changed oils and had a measureable difference in performance / economy with all other factors not changing?

JohnD · Post by **JohnD** » 28 Oct 2003, 23:21

If your engines have a good number of miles under their belts, I wouldn't recommend changing to a fully synthetic oil. Others have done it and found the oil consumption has shot up.

rabenson · Post by **rabenson** » 28 Oct 2003, 23:26

I agree with JohnD - apparently can make old oil seals start leaking too....

Kered · Post by **Kered** » 29 Oct 2003, 02:10

Well now, I have a 95 VSX TD - from new - that has done 110,000 miles. I live near the South coast and I am able to get to France on day trips quite easily (and cheaply). Apart from filling up with diesel and booze [;)] I obtain my servicing spares from the Auchan or Carrefour Hypermarkets. For the last 4 years I've been using fully synthetic 5W40 (at around £13 for 5 litres! - all of their oils are far cheaper than ours!! WHY?????)and have had no oil burning at all. I still have no need to top up between oil changes as the dipstick level doesn't drop.
I can't comment on improved fuel economy but the engine sure spins faster while cranking. When emptying the old oil into the oil tank at the recycling depot it pours like water! or like ordinary oil is when it's hot. Don't forget that the 5 part of 5W40 is how it acts when cold and the 40 part, when hot.
I tow quite a heavy caravan all over europe and often have the throttle pedal floored in 3rd for a minutes at a time but I feel more comfortable about it with this oil and have had no ill effects.
Derek

Kowalski · Post by **Kowalski** » 29 Oct 2003, 14:31

Heavy caravan? 3rd Gear? Pedal Floored? Minutes at a time?
Remind me not to buy your Xantia when you sell it.

arry_b · Post by **arry_b** » 29 Oct 2003, 15:50

I've moved from mineral to semi synthetic to fully synthetic in my 87,000 mile ZX and the oil consumption has dropped to almost nothing. No oil seal leaks have sprung up either. I did the same on my 160,000 mile Mazda with no ill effects either. I've not noticed and real difference in fuel consumption, how I drive has the biggest effect.
The engine felt much smoother when I changed from mineral (Comma Diesel with 3k on the oil) to semi synthetic (Duckhams QXR Diesel), really very noticable. Less of a difference between semi and fully synthetic (Duckhams again). A colleague uses the Quartz oils in his Volvo that GSF sells and reckons they're good as well.

Kered · Post by **Kered** » 01 Nov 2003, 00:40

Hey Kowalski
How did you know it's for sale?[?]
Actually it has got to go - not that there's anything wrong with it - but it's been brought to my attention that the towing weight is restricted to 1200 kilo and my caravan weighs more than that.
I am advised that the Xantia 2 or facelift, has had this raised to 1500 kilo. Can anyone confirm this from their car manual rather than hearsay? I rather fancy a 1999 - 2000 HDi estate if it will do the job.

JohnD · Post by **JohnD** » 01 Nov 2003, 15:26

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Kered</i>

Hey Kowalski
I am advised that the Xantia 2 or facelift, has had this raised to 1500 kilo. Can anyone confirm this from their car manual rather than hearsay? I rather fancy a 1999 - 2000 HDi estate if it will do the job.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
The maximum towed weight (on paper) may well have been raised to 1500Kgs, but the kerbweight of the Xantia is still only 1336Kgs to 1380Kgs. for the Estate. (1429 for the 2.1 Estate) The ideal towed weight should be between 85% and 100% of kerb weight.

Stuart McB · Post by **Stuart McB** » 01 Nov 2003, 16:01

I recently used the Quartz oil from GSF on my ZX td 144K and the engine is now really quite compared to using the Halfords stuff. So far oil level is the same. I have recently managed to get 430 mls out of £32 of fuel which I think's great compared to some cars I've run. My Xsara 1.6 VTR needed filling up after only 300mls on the same amount of fuel. I do 60 mls a day to and from work but half is open road and half is in the city (Birmingham) . So far so good.

Kered · Post by **Kered** » 01 Nov 2003, 22:19

Thanks JohnD
I am, of course, aware of the 85% rule. My caravan has a max weight of 1219Kgs, which for my current Xantia put me in the 95% area. I've towed for over 10 years with various cars and caravans and find the Xantia makes for a very stable tow vehicle even at 95%. I suspect this is due to the very short rear overhang plus I have a VSX with low profile tyres so there is less tyre wall movement.
My concern is one of insurance. If, God forbid, I'm involved in an accident and the caravan is found to be over the 1200Kgs limit then I'm in trouble. This is a completely separate issue to 85% kerbweight.
Derek

tudor · Post by **tudor** » 02 Nov 2003, 13:19

Anyway..? Getting back to the subject of fuel economy. lol
I agree with JohnD,stick with what your using now.
Regards Tudor

Nikolaymk · Post by **Nikolaymk** » 02 Nov 2003, 18:36

What makes a difference for me is the condition of the oil - not the type. After my last oil change my mpg improved. Not a dramatic improve but still something.