Andrewwood Posted July 3, 2015 Posted July 3, 2015 Hi allI've just bought an 05 plate C5 2.2diesel exclusive auto with 57k on the clock.Two issues really, one is the Auto box (never had one before), the gearing seems pretty high to me as 4th gear don't come in until about 50mph is this correct? Also when cruising at above say 60, the car is noisy as though being over revved but according to the rpm counter it's only doing between 2300 - 2500rpm, wondering whether this has anything to do with automatic box OR maybe a 'sports' exhaust or removed DPF. The exhaust seems fine at tickover and no apparent noise when I 'blip' the throttle when stationary. I still have my 2ltr C5 02 plate (MOT failure) As well as this one and I must say it is quieter on the road than my new one. Any help or pointers would be appreciated Andy Quote
paul.h Posted July 3, 2015 Posted July 3, 2015 A quick check that may indicate if the dpf has been removed is to look at the exhaust tail pipe - on all our diesel cars with a dpf they were clean metal internally, ones without a dpf were covered in soot. See how the old and new cars compare. I have not had an auto but doing 2300-2500 rpm at 60 mph seems a bit high. A manual gearbox would be less than 2000 rpm in top gear. Data for the gearbox for the 2.2 hdi 136 bhp mark 2 C5 215/55/R16 tyres: HP20 (AG) box,4th gear at 1000 rpm speed 49.36 km/h = 30.85 mph.3rd gear 1000 rpm 35.52 km/h = 22.2 mph.2nd gear 23.98 km/h at 1000 rpm = 14.99 mph.1st gear at 1000 rpm 13.07 km/h = 8.17 mph. For the AM6 auto box on the 2.0 hdi for 6th speed 49.46 km/h at 1000 rpm = 30.91 mph. So possibly the car is not geting out of 3rd gear at 60 mph. Quote
Andrewwood Posted July 19, 2015 Author Posted July 19, 2015 Thanks for the reply Paul. It's definitely getting into 4th gear both in auto and manual modes. It's actually doing 2100 revs at 65mph. Just wonder if it could be say a tyre noise or similar it's got 4 new Firestones on,it doesn't sound or feel like bearings anywhere and of course being auto I can't coast or freewheel down a hill at 60 to see if it's engine related or something else. Andy Quote
paul.h Posted July 20, 2015 Posted July 20, 2015 You could look up the tyres and see what noise level they give in dbels. Quote
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