Citroen C5 2.0 Hdi Vtr 136 (Fap) Excessive Fuel Consumption

[adpace8]

Hi everyone, i am new to the forum and am seeking some useful advice on a problem i am having with my Citroen.

 

I purchased my 2008 C5 2.0 HDi 16v last December, at the time it had done 104,204 it has now 108,018. I purchased the car as I am covering a lot of miles per month and needed a car which was comfortable, had a big spacious boot and most importantly returned more MPG.

 

However, while my C5 drives well and without fault I can not seem to get anywhere near the quoted 48MPG. The best I have managed is 42MPG on a long run to Southampton which is 95 percent motorway driving and it should have returned around 56MPG. I cover around 300 miles a week normally and my MPG has hovered around 39 - 40 MPG.

 

I have serviced the car changing all filters and using Mobil 1 oil, I have also used Shell V-Power Nitro+ for 3 weeks in order to give the injectors a good clean out, I also put some Redex through to further clean the injectors this did nothing it would seem. I also only use branded fuel and not cheap supermarket fuel.

 

I have no warnings lights or warning logs. The car drives spot on and pulls brilliantly.

 

I am suspecting an injector fault, that maybe 1 or 2 are just dripping fuel rather than spraying the fine pattern they should be.

 

I have not had them tested as I have been quoted £120 per injector.

 

I have recently changed the oil and filter again using Total quartz INEO ECS ACEA/C2 and a genuine Citroen filter, I only did this today so I will not know if it has improved my MPG.

 

Any advice on this matter would be much appreciated.

 

Thanks.

[Johndouglas]

Have you checked that the brakes are not binding. Sometimes a stuck caliper can stop the pads from releasing. Also check the handbrake cable. If the inner cable gets damaged it prevents the pads releasing.

[adpace8]

Thanks for your post Johndouglas.

 

I have considered that the brakes could be binding but have never checked it as the car pulls fantasically through all the gears and gets upto speed easily. Would binding brakes could the car to achieve 7MPG less than quoted?

 

However, i do get what sounds like a booming sound  when braking down from motorway speeds, this could excessive run out distortion on the discs though rather than binding.

Nevertheless I will check them after work tomorrow.

 

Thanks for the advice.

[paul.h]

what mph are you doing on the motorway ?

[adpace8]

Paul.h thanks for your reply.

I get upto to 70 and stick the cruise control on. The max I go to is 80 but as i am battling to improve my MPG I dont do this regularly.

[Johndouglas]

If you are regularly travelling with cruise at between 70 and 80mph, I think you have the answer to your problem. Try a motorway journey at 65 or so. You'll find it will only take a few minutes longer and you may be surprised at your fuel consumption.

[paul.h]

That is what I was thinking, I find on our C5 estate 2.2 hdi 173 bhp and our previous C5 hatchback 2.2 hdi 136 bhp that if you go around 65 mph you get another 5 or more mpg compared to 70 mph. Much above 70 mph and the fuel use increases a lot. On the M60 there is a section of roadworks for 20 miles at 50 mph with speed cameras, through this section the fuel use drops dramatically. Last 2 days I went from Warrington to Lincoln and back, 130 miles each way of which 2 miles are town roads, 25 miles a 60 mph limit and the rest motorway - going gave 47 mpg keeping to the speed limit but return was 51 mpg keeping to about 65 on the motorway (apart from an 11 mile queue on the M60 on the return). The same journey in our C4 1.6 hdi would give about 70 mpg. Wind direction can also affect fuel use.

 

I often think when the large 4x4 cars go past in the 3rd lane at over 80 mph they must need to stop frequently to refill the fuel tank and lose the time they saved by driving fast, never mind being a danger to everyone else on the road.

[jocm1]

I'm getting at least 50mpg on a 65 mile daily round trip same car but the tourer I never use the cruise control  - I feel I get less mpg with it on but have no evidence for that

[paul.h]

If it is hilly I have read that cruise can use more fuel going up hill since it will try to maintain the speed compared to letting it drop a bit which will save fuel. Possibly if needing to slow down cruise will keep up the speed until the brakes are used whereas without you would lift the accelerator a lot sooner. We need adpace8 to try 2 identical trips with and without cruise. 

[Johndouglas]

Yes - I think that with cruise on once the car gets off level ground, fuel consumption increases. The steeper the hill, the greater the increase. I've noticed it particularly when towing up hills.

 

:rolleyes:

[adpace8]

Hi guys,

 

I have tried out doing 65 mph on the motorway on my last 4 22 mile trips. And there doesnt seem to be any change in fuel consumption.

 

The range indicator reads incorrectly so i cannot use that for an accurate reading. Every week i put fuel in nd i have done around 300 miles or so, the range says i have averaged 44MPG but when i have calculated it based on the miles covered and the fuel added it works out to around 39.7MPG.

 

It is currently showing i have done 44MPG based on 220 miles. But as it miss reads i have to assume 39-40MPG.

 

jocm1, what is your driving style like? And also, what kind of roads do you use on your 65 mile trip? I have never seen 50MPG in mine. You would think your C5 would use more it being an estate version as it is slightly heavier than the hatch.

[paul.h]

Just need to ask, is your car an automatic gearbox or 6 speed manual ?

 

From a 2007 sales brochure the official mpg  urban / extra urban / combined for the hatchback is 36.2 / 56.5 / 47.1 mpg for the 2.0 hdi 6 speed manual and 28.2 / 51.4 / 39.8 mpg for the auto 6 speed. It gives identical values for the estate version 2.0 hdi.

 

For our 2.2 hdi estate 6 speed manual it gives 34.4 / 55.4 / 45.6 mpg which considering I get 45 to 52 mpg on motorways suggests you should be getting a lot more than you are if you have a manual gearbox. My driving style though is steady and not hard acceleration, changing up a gear as soon as the engine has enough revs (probably 2000 rpm or a bit less due to it being a diesel), keeping to or below speed limits, not using cruise, gentle braking and lifting off the accelerator pedal early when needing to slow down, not driving close, not racing up hills and not accelerating down hills.

 

Have you reset the trip computer ? This is done by holding in the button on the end of the wiper stalk. Also once 9999 km (6248 miles) is reached it stops working and needs to be reset since it does not have enough digits to go higher. If you have not been resetting the computer try doing it before each trip to see what it thinks you are getting. I find the town driving sections hit the fuel economy badly.

 

A quick check if the brakes are binding without jacking the car up is to feel the wheel hubs to see if they are hot.

[Johndouglas]

Do you happen to have roof bars fitted?   I know from experience that a rack (even without a load on it) will impact on mpg figures.
Paul's quoted figures of 36.2 / 56.5 / 47.1 mpg is exactly what I get.   Recently I did an airport run of 40 miles each way along a hilly coastal motorway.   The figure shown on the display was 54mpg.   Now with a bit of running around town it's showing 246 miles at 47.6mpg.   On this car I haven't compared dashboard results with actual measured tank filling but on my previous C5 I did and the two results were very similar.

Don't forget that fuel consumption figures are always lower in the winter months.  

 

Edit.   The results I've quoted would be for typical 'summer' figures.   The car is abroad at the moment. 

[paul.h]

John, just had a look in a November 2009 C5 sales brochure and for the tourer 2.0 hdi 160 6 speed manual gearbox it gives 39.8 / 57.6 / 49.6 mpg for urban  / extra urban / combined. Hence the 2008 on C5 model official figures appear to be slightly more fuel efficient than the 2004 to 2008 C5 of adpace8.

 

Something else adpace8 could check and that is if it is getting up to temperature quickly and then staying there - the coolant temperature gauge should be half way after about 2 or 3 miles. If it is not then possibly the thermostat needs replacing since a cool engine will use more fuel.

[adpace8]

Thanks for all you replies and advice regarding my issue.

 

paul.h, i have the 6 speed manual in my C5. I reset the trip meter on the dash and 1 of the trip meters on the computer whenever i add fuel so i can calculate my actual MPG. The second trip meter on the computer is reset every month. As i have said it does not provide an accurate reading (usually 4-5MPG less than actual).

My driving style is the same as yours. I change up at 2,000 rpm, i do not use hard acceleration as quite frankly, with the turbo kicking in at 1,500 rpm a gentle push on the throttle gets the C5 upto speed quickly well without working the engine too hard. On the thermostat front, she does seem to take her time getting upto to temperature, usually about 4-5 minutes. would a faulty thermostat throw a EML or a fault on the warning log?

 

Johndouglas, i do not have a roof rack fitted. Also, i have read somewhere that cold weather can reduce fuel consumption on a diesel. How much can it decrease by? 

[paul.h]

A thermostat opening early would not give the eml or any warnings but 4 to 5 mins to reach mid point seems ok. So it looks as if you are doing everything that should give good fuel economy.

 

Cold weather reduces fuel economy due to longer to warm up and also there are winter additives in the diesel so it does not freeze. However, unless your journeys are all short ones it would not make the 5 to 10 mpg difference you are seeing.

 

We have a C4 owner whose fuel economy is bad, even on long runs but these are offset due to driving around London each time. So if you are stuck in traffic in town then this would help explain a poor fuel economy.

[adpace8]

Paul, i will give you a more detailed description of the warm up. When i set out to work in the morning i use the M54 and i live about 1 mile away from it, it takes about 3-4 miles to warm up on the motorway at 55-60mph. My trip to work is 22 miles. 18 of that is motorway and the rest normal roads with no traffic. However on Wednesday and Thursdays i have to travel 5 miles from work to my mom's to pick up my son. I do not use a motorway to get there and it is not quite fully upto temperature by the time i arrive at my mom's. Is this normal? 

[Johndouglas]

The two C5s which I've owned have both been slower to warm up than a Xantia or BX or even the Saxo which I still have.   Just this morning I used the C5 for a quick trip to the shops - a journey of four miles there and back.   The two temperature gauges were just reaching their usual spots as I arrived back.

[adpace8]

Based on your input John it seems normal.

 

I must have a dripping injector or maybe 2 dripping injectors.

 

I will be checking the glow plugs saturday morning (weather dependant) to see if they can show some signs of an incorrect spray pattern from any of the injectors.

 

I will let you guys know of the results.

[seefive]

Just to make you feel better..I get 32mpg  in my 2006 2 litre auto.

That's because I live in a hilly area and most of my "journeys" are less than 5 miles.

I've given up worrying about the numbers, and they're about right anyway, per the official consumption quoted above by Paul

As my monthly fuel bill is around £50, my scope for saving with a more efficient car is not exciting.

 

MPG has become an obsession with a lot of people, and they lose sight of the true cost of owning a car. 

 

[paul.h]

With your described journeys you should be getting decent fuel economy. How does it compare with your previous car ? Maybe try resetting the trip computer for the motorway bit to see what you get, then any warm up/hills/town bits at the start and end will not affect the value and I would think it should be around 50 or more mpg.

 

The best way to check the thermostat is with a code reader that does live data. Then you could see what temperature it is opening. Without one you can let it warm up whilst parked and feel the top radiator hose, when it starts to warm up the thermostat will be opening and then you can compare it against the temp gauge. However, if the gauge is at mid way (9 am/pm) and does not drop when on the motorway I would think the thermostat is ok.

 

Where are you getting your fuel from, maybe you could try a different supplier although having tried Shell you have already done this test ? I use our local Sainsburys since to go anywhere else would involve quite a few miles.

 

You say you have changed the filters, does this include the air filter ? The timing belt is not yet due for changing but do you know if it has been done anyway ?

 

Do you know if the car has had the exhaust particulate filter (dpf) removed or knocked through and if the egr valve has been blanked off and if the engine has been remapped ? These mods can affect the fuel economy. Have a look inside the exhaust tailpipe, it should be clean metal if the dpf is present and working but if it is sooty then it may have been removed. You can also check the maintenance record, the dpf should have been replaced or cleaned and the eolys fluid refilled by now.

[coastline taxis]

hi when your driving what do you have switched on as the heaters,air con.wipers,demister,s and even the stereo eat up fuel  also the driving figures ar basicly a load of chit as there done on a rolling road with no wind factor or anything switched on and only 1 gallon of fuel in the tank. to get the true figures fill your tank right up so you can see the diesel in the neck of the tank then drive 100 miles in your normal driving style. Once you reach 100 miles then go and fill it back up to the neck. then do the maths

[adpace8]

Paul, my previous car was a 2 lire petrol Kia Magentis which gave me 33MPG, I only sold it to get a diesel as i have a trip of 50 miles a day to and from work and was putting £50 a week in the Kia.

 

The temperature doesnt drop from 9am/9pm position once warmed up, so it must be fine.

 

I always try to use a fuel brand thats the same as the brand of oil i have used in the engine. When i used Mobil 1 oil, i would fill up with Esso fuel. I used Asda fuel once but the engine seemed to not run as smooth or perform as well on this fuel. It improves alot when using a branded fuel. As i have changed the oil again since the Mobil 1 oil, I will be filling up with Total fuel as i have used Total Quartz fuel economy oil. To summarize the fuels I have used are; Esso, Shell, Shell V-Power Nitro+, BP and ASDA but I only used this brand once and will not be using it again.

 

I changed all filters (Air, fuel, pollen and oil). I have no record of a cambelt change and i know it does not require a replacement until 160,000 miles according to the Citroen maintenance guide.

 

I have no evidence of an engine remap. I know the version of C5 i have should have a DPF on and i am sure it is still on the vehicle. For instance, when started from cold on a cold morning the exhaust smells abit, but when i get to work after a run on the motoroway, it smells much cleaner so clearly the DPF has done a regen. Also, the eloys fluid is due to be replaced @ 120,000 miles. i have been aware of this for sometime now and got a quote from Citroen last week of £340 INC VAT, which to be honest i expecting more as I have been told it could cost as much as £500. The guide does not state a DPF replacement mileage or time frame,  but I am sure they are designed to last for the life of the car. I will do the checks you have suggested tomorrow morning when I am checking the glow plugs and report back with the results, I will also check the EGR as I have got to move the cooler pipes and valve out the way to get at the glow plugs.

 

coastline taxis, I reset my trip meter every time I add fuel and calculate my MPG and I am averaging 40MPG.

Edited February 19, 2016 by adpace8

[paul.h]

A search suggests the Kia should give about 36 mpg combined so maybe your driving conditions cause you to use about 10% more fuel in your cars. If so then the C5 instead of giving about 47 mpg will give about 42 mpg and this is possibly about what you are getting.

 

£340 seems a bit steep for putting in the eolys fluid. It takes about 3 litres to completely fill, cost about £100 plus labour (book time about 45 minutes) and then a diagnostic to tell the car it has been topped up, otherwise you will get messages saying the level is low. The level is not measured, just calculated on the number of fuel tank fills. People on here say the fluid will continue to be added if you have the warning message if the diagnostic is not done so that the dpf will continue to be regenerated.

 

In the Maintenance book with our 2007 C5 under Particle filter it has for the C5 2.0 hdi;

- 80k miles top up eolys 176 fluid

- 120k miles replace particle filter (it does not mean replace the eolys fluid).

 

So from this, provided the eolys fluid was topped up at 80k miles it should not need doing again until 160k miles.The dpf however may be due for a change or clean but most people would probably wait until it gave problems due to blocking up. Check the exhaust tailpipe though in case the previous owner had the dpf removed or knocked through.

[adpace8]

The Kia i had was a 2003 model. And the offical figure was 32.7MPG. The newer ones gave the figures you found Paul.

 

I have just checked my maintenance book and misread the schedule and is does say to replace at 120,000. Got a quote from Citroen which was £350 inc VAT, 12 month guarantee, fluid replaced and a forced regen.

 

Looked at the exhaust pipe (without a torch as i could'nt find it) and it does look abit black.

 

If the DPF was on its way out i would experience excessive fuel consumption. Not sure of it would be as much as mine though.