Diesel MPG/Oil Filler cap

[sawarren88]

Hi All, Still on a learning curve with the 406 2.0 L 90 HDi I bought in December. Have just come back from a trip to France and apart from a minor bump (no damage thankfully) the car ran very well but my mpg on the trip worked out around 42 mpg - lower than I expected or am I being unrealistic - most of journey on motorways. The car had also used a small amount of oil - is this normal with the HDi

I have also noticed that after most journeys the oil filler cap has rotated slightly - I tighten it up again but it had moved again by end of my next journey- the dipstick has also been raised from its rest position. Is this a common thing or is it a case of replacing the filler cap.

Thanks in advance for any help or siggestions

Steve

[GeordieBoy]

42mpg on the 90 is prob ok for motorway if you been doing 80mph. My 110 gets about 45-50mpg at 80mph. It doesn't lose oil but it has blown the oil cap off twice. Dip stick also rises a bit in mine, its prob just excessive pressure if ur hammering it a bit.

[jameslxdt]

your dipstick and oil cap will come loose if you have excess crankcase pressure which could be a result of worn piston rings or a blocked pcv system

[diesel.weasel]

I have a 90 hdi with a dragon performance chip. I drive 200 miles everyday to get to work and back and consistently get 52 mpg.

The road is for the most part dual carridge way and I sit at 80 when the traffic allows.

Your mpg might be down because you had a car full of suitcases and 45 gallons of wine on the way home?

Using oil in smallish quantities is fine. I have to put in about 1 litre between oil changes (12,000 miles)

DW

[DaiRees]

Using oil in smallish quantities is fine. I have to put in about 1 litre between oil changes (12,000 miles)

I put a litre in my 4X4 every 500 miles or so....

[Welly]

In truth, I would have expected more than 42MPG. Something like 50 would be more usual.

If I take my car (a 110 HDi) on a 200 mile motorway run at 90MPH I allways get 48 - 50 MPG

You can experience slight oil consumption on high speed runs but generally I get no oil consumption whatsoever with no top ups between services.

I have never experienced crankcase pressure build up on mine and I would seriously consider getting it checked out. Otherwise you will end up with oil mist being forced into the inlet and coking up.

[sawarren88]

Hi All, Thanks for all the replies - will have to get the car looked at asap if it is a pressure problem. Beginning to wonder if the mileage is genuine but will take that up with my mates dad who sold me the car. The car is so immaculate inside it feels low mileage but the few faults that are becoming apparent make me wonder.

As to the mpg there may have been wine on board !!! on the return journey and we were travelling at around 80ish so perhaps it is a fair figure.

Anyway enough of my minor problems - thanks to all for the replies.

Steve

[richyb83]

I've got a D9 90 GLX and usually get about about 650 miles from a full tank doing mixed town and motorway driving (probably town bias) but on longer motorway runs I have achieved as high as 860 miles from a full tank. Thats crusing along with a full car load at 75ish. Got to love those HDI's. Don't want to go into too much depth but thats got to be like 7p a mile which is pretty good these days I reckon.

[Welly]

Oil qualty can play a big part in controlling oil consumption.

Maybe it's not been treated to good quality oil, or the oil in there is past it's best.

You should get the breathing checked and sorted out though and THEN I would do an oil flush and fill with good oil (a 10W/40 semi synthetic should be fine) change it twice a year or every 5000 miles ish.

I'm a bit 'nerdy' about oil changes and do mine every 3500 miles (mind you I only do 7000 miles a year) crappest excuse to run a Diesel evAr

[richyb83]

I just got a can of oil flush, was going to put it in on the weekend and do an oil change. First time ever using one so I have to see if I notice any difference. Might be the case that I just 'imagine' a difference which I am sure is very common among car people. Had a friend fill his 1.1 saxo with super unleaded and he swore he could feel considerably more power. Very doubtful in my opinion!

[jameslxdt]

ive got a friend with a saxo 1.1, we made a custom induction kit, and exhaust system and ran it on bp ultimate, we had it on the dyno and it gained 7 bhp, which i thought was good for a 1.1, and you can feel the difference

[stek1961]

My diesel turbo, not sure if it's a 90 or 110 refuses to better 40mph which is a bit rubbish.

I do 100% to and from work Manchester to Leeds M62 speed ranging from 70-90 mostly 80-ish. Just had it serviced so now I'm watching the miles but it doesn't look any different on this tankful.

190,000 miles but drives perfectly!