Aletheia

Vehicle:

Mazda 3 (2014) 2.2 D Sport Nav SKYACTIV-D Manual Transaxle

VIN: JMZBM642611171664

Mileage: 140,000



Problem: Severe Vibration When Engaging Clutch Biting Point at 750 rpm.



Problem Summary: Vibration is Apparent Moving-off from Standstill in 1st Gear and Reverse. Vibration is Also Apparent Manoeuvring at Low Speed into a Driveway or Parking Spaces etc. Vibration is Detectable Moving-off in Second Gear at 1,200-1500 rpm and Occasionally Changing Down from 3rd to 2nd Using Synchromesh.



***If anyone can shed any light I’d be most grateful. There is a detailed history below if you’d like to read on.***





Vehicle History:

The vehicle has been meticulously maintained since new by Mazda main dealer:

Super-diesel fuel

Oil changes every 6,250 miles

It has wanted for nothing.





Mechanical History of Problem:

Thu 14-3-19: 63,153: Laboured knocking effect when starting engine cold.



Sun 26-5-19: 66,230 miles: ?Clutch-related, cyclical ‘knocking’ sound when clutch is let up slowly at low revs, plus noisy clutch at idle until clutch depressed.



The knocking effect above came and went over many miles but slowly worsened.



6-12-22: 137,472 miles: DMF/Clutch assembly replaced. Mazda declared that DMF almost certainly the culprit and definitely out of spec as an original part at this mileage.



Upon return there was a floor pan vibration and the clutch pedal was out of adjustment and there was a vibration engaging the clutch.



Mazda immediately replaced the clutch, stating it would all be new again as it’s a ‘fit-once part’. This fixed the pedal and the floor pan vibration but the vibration engaging the clutch remained.

I returned with the car and stated my dissatisfaction but was given a range of suggestions that, “…these cars do tend to vibrate etc.” As I intended to keep the vehicle I undertook a series of investigations with other garages and also replaced all of the engine mounts over a period of 9 months. Each replacement made a noticeable improvement to the ‘tightness’ of the engine but did nothing to improve the vibration. All four garages I had examined the car suggested it was the clutch.



I spoke to LUK, the clutch manufacturer who were amazed Mazda weren’t using the self-adjusting clutch tool to fit the clutch as this would mean it could be taken on and off many times, as it is in no way a ‘fit-once’ part.



I wrote to Mazda with my battery of information and they replaced the clutch for a 3rd time, making twice at their expense, with oversight from the manager.



After 3 days of attention, the clutch still vibrated. So they undertook some further investigation in the form of a compression test and leak down tests. These showed that all cylinders were at or below the minimum 261 psi at 180rpm.



Their official diagnosis is that the low compression is causing the vibration at low revs.



However….

Two weeks after accepting back the vehicle the master warning light came on and briefly, the oil light. Mere seconds later I shut down and coasted to a halt. The long and short of this was that the Skyactiv-D 2.2L curse of leaking injector washers was to blame and the oil strainer was replaced, injectors cleaned and washers replaced etc. No further compression test was performed.



With the vibration persisting I took the car to a firm of vehicle engineers and asked them to assess the vibration problem. This is ongoing due to lead times with booking in but the investigations to date and results are:

• Initial use of Forté Advanced Formula Diesel Treatment and a hot engine drive at 4-5000 rpm. This noticeably improved fuel consumption by 6 mpg but made no difference to the vibration.

• With the injectors seals now fixed a compression test was performed which showed excellent compression throughout all cylinders, completely invalidating Mazda’s theory. This made no difference to the vibration.

• The vehicle is smooth, powerful, has never had flat spots, does not use oil, produces clear exhaust, has never had a DPF problem and does not use coolant.

• The exhaust pipes are clean and an emissions test produced a result of “Too clean to test.”

• We will shortly do a borescope check but personally, I don’t expect that to reveal anything.

• On these cold -2°C mornings the engine strikes up immediately.

Nothing about this seems to suggest to me that this vibration has to do with poor compression, although I am no expert.



The vehicle will vibrate like hell engaging the clutch at 750+ rpm but then drive on nil throttle up an incline as smooth as silk at 700-750 rpm, under load.



My Request for Help:

Thank you, if you have read this far!



Would anybody have any suggestions as to what could be causing this vibration? It has persisted through (presumably) three new DMF/clutches, new engine mounts and improved injector nozzles from cleaning and improved compression from fixing the injector seals.

Christian89

Hi,

I have or had a similar issue with mine, it improved a lot when my injectors were replaced. But I think I have the bad clutch and flywheel as well. Vibrations in the cabin at idle and very slow bite in first gear.

Do you know how often your car is regenerating? The fuel in your oil could have been due to stoping mid regen rather than dodgy seals, and with bad injectors that will be happening a lot more often.

I have read on forums that it’s a common issue with our vehicle, and the common consensus is that it’s condensation, but should go away once warmed up.

might be worth checking your master slave and slave cylinder.