C4 Intermittent Unstable Driving At High Speeds

[bungalowbill]

Hi all, sorry for the long post - at my wits end.

 

I've had my 2013 C4 (1.6 HDi (115bhp) VTR+ 5d) since August last year. It was a Citroen Select approved used car from a Citroen main dealer. It's now done 44k miles.

 

This was my second C4, replacing a 2011 model.

 

I have a problem in that, intermittently, the car is nervous, skittish and unstable at anything above 50mph. Some days I can bomb along at 70mph and the car feels assured, glued to the road, safe and stable. Just as quickly, the next day I can't get above 50mph before it feels like it wants to chuck me in the next ditch - the car seems to be floating on the road, and every bump or turn is scarey, with shimmying and lateral movement. Sometimes under breaking or acceleration, the back steps our or shimmies from side to side.

 

The problem is, it's not all the time - as I said, I can do a day where it feels like it owns the road. The next day, I can't get the speed up because it's so unstable I'm petrified to drive it.

 

It's not Tyres or Tyre Pressures - I've changed all four tyres for brand new premium tyres, this didn't fix it. I check the pressures regularly, and they are always spot on (33 front, 30 rear). I don't think it makes a difference whether it is full of Diesel or not (thinking it might be a weight issue) although I have felt it is generally more stable the heavier it is - but not always.

 

The garage have taken a look at it on 4 occasions and can't find a fault - although they have only done cursory examinations of the underneath and visual inspections (without dismantling) of the suspension. There is no evidence of any damage from previous owner either.

 

If I measure the gap between the rear tyre and the bodywork there is a marked difference between the left and right - the gap is wider on the right-hand-side, by about 5-10mm. The garage said this was fine, saying it depends on the geometry of the car when it is resting - the only way to test is to strap the car down and compress the suspension then measure it - they've done this and say the gap then matches.

 

I took it to an independent wheel alignment centre who said the rear geometry was out so much they estimated the rear would crab by 11 metres for every KM I drove. It also cannot be adjusted. The main dealer would not accept their examination. Either way, I am not sure that is the cause as if it was that bad, I would have problems all the time - but I am only having stability issues 60% of the time.

 

Any ideas what it could be? The dealer won't look at it again. They even suggested it was in my mind - but as its only intermittent AND I've had an identical C4 before, I know it's not a characteristic of the model.

 

Help!

 

Bill.

[paul.h]

Welcome to the forum.

 

Has the dealer test driven the car with you so they can see/accept there is a problem ?

 

We are on our third C4 and never had any stability problems, always used Michelin tyres, what make do you have on now and before ? I always use the tyre pressures at the max value at the front and mid value for the rears. Is your presure gauge correct, maybe try a new one. Are the tyres wearing evenly - run your hand over the tread to check for feathering which would indicate the tracking was out.

 

The suspension should be the same height at both sides but anyone can pull the car down so it seems right but strapping the car down to get the height right is done when checking the castor/camber/king pin angles. Have you checked for broken coil springs such as a bit missing off the end coil ? You could measure the wheel arch gaps on new cars at the dealer to check if they differ across the sides with them.

 

I once had a Saab where it was unstable, especially going over manholes but I had just replaced the steering rack and had not got the tracking set up, once this was done it was ok again.

 

It is possible the car has been in a crash and maybe not repaired properly. Are there any signs of newish paint anywhere or under the car or slightly different shades ?

 

With a Citroen select approved used you should have a 1 year warranty (unless possibly from a car group like Evans Halshaw) which can be used at any Citroen dealer so you do not have to keep going back to the same one.

 

I do not know if it is too late to reject the car but under current legislation if there is a problem dealers get 1 chance to fix it and then you can get your money back. Have a look at this topic http://www.citroen-owners-club.co.uk/citroen/topic/21408-new-c4-front-brake-pad-clean-or-replacement/ You could also see if the dealer will part ex it against another car - that would let you know if they know something is wrong with it.