Q My car is using a lot of oil; I can’t see any smoke is it burning it?
A Well how much is a lot, if it’s more than 500ml (half a litre per 500 miles 1L per 1000 miles) then yes, the engine is on a downward spiral. It’s Likely that the oil control rings are gummed in place allowing excess oil to enter the combustion chamber. It will consume more oil until one of two things will happen
1. An exhaust valve will burn away as the engine will be running extra hot when low on oil, causing the engine to go onto two cylinders, and it will have no power and will sound strange
2. If maintenance has been sporadic the next thing to go will be a spark plug, the electrode will overheat if the oil is to low or oil will cover the plug and cause an electrical short circuit increasing the risk pre ignition see note why is the correct oil and fuel and plugs so important.
Q Can I just replace the valve that’s burnt out?
A No it will burn out very quickly, it would be like putting a plaster on a broken leg, the problem will happen again (as quickly as 3 weeks, we have seen works completed by other ‘experts?’), the only satisfactory option is to replace the engine.
Q Why are these engines so weak? Why are they be worn out so quickly?
A Well firstly lets get this into perspective a 61bhp 599cc car is making 101.83 Bhp per litre very impressive that’s the same power as an E36 BMW M3 all from that little engine with only 2.7 litres of oil to cool and lubricate it. Most are driven flat out, full throttle everywhere, often poor maintenance, sometimes only 3 spark plugs have been changed (they have 6: two per cylinder) and the wrong oil, low grade fuel. There are many running high mileages and achieving 55+mpg, they get a gentler life
Q Why is the correct oil and fuel and plugs are so important?
A Oil 0w – 40w (UK spec) Fully Synthetic, Mobil 1 is recommended (We have tried other oils but the smart does not like them, it burns them differently and quickly!)
NB. The Smart turbocharged engine puts special requirements on fuel. Turbochargers make more power, in doing so increase the temperatures the engine has to deal with. High temperatures can cause pre ignition or knock, this is where the higher temperatures and increased combustion chamber pressures can cause the fuel to ignite prematurely and uncontrolled, if this happens it could burn out a valve almost instantly or indeed destroy a spark plug as detonation is uncontrolled explosions in the combustion chamber, these create many shock waves as the mixture spontaneously explodes putting the spark plug under immense pressures.
Higher octane fuel RESISTS premature exploding better so the engine can run closer to its limits for making decent power without having to ‘back off’ to preserve the engine. BRABUS models are meant to use only 98+ Ron fuel (indicated in the fuel filler flap) There are additional cleaning additives used in premium fuels but we do not have test data to prove or disprove the usefulness in Smart applications.
NB Spark plugs must be changed as per the service schedule, failure to do so will could mean pre ignition (see above) or plug failure or destruction either of which could mean engine failure
Q Why is my car is having trouble selecting gear?
A It could be one of several things
1. Check the rear lights to see if the brake lights are working if not then its probably the brake light switch faulty and need replacing, its between the under tray and the car chassis and really need the car on a ramp
2. Then the wiring to the gear selector motor need to be checked to see if the intercooler shroud is chaffing the wiring causing electrical short circuits, if so the wiring need to be cut and rejoined and the intercooler shroud modified so it wont damage the wire again
3. Check the clutch actuator adjustment and operation
4. The clutch unit may be worn and need replacing, always replace the release bearing at the same time.
Q When driving slowly I get a weird spring sensation through the brake pedal and a noise to accompany it?
A Get someone to check the ABS Reluctor rings (they are at the end of each rear driveshaft), these corrode and split over a period of time making the abs not work when it should be, the split rings give incorrect signals to the ABS sensors that in turn makes the abs pump unit work when it is not required. Get new driveshaft's or have a qualified person replace the abs timing rings.
Q My 42 Steering is stiff, someone said it might be my power steering?
A Well its unlikely to be that on a 42 as most don’t have power steering, it more likely to be the universal joint in the steering column there are two, one inside the car and one outside the car but under the under tray, it is exposed to all the water and rubbish thrown up from our roads, there are two options replace the steering column or to remove it and clean it and re lubricate it and replace it.
2. Roadster yes it could be your electric power steering, they can work intermittently causing the steering to be easy or difficult as the power steering goes on and off again, clean and check the electrical terminals and check the wiring if it continues it may require a new power steering and rack
Q My 42 headlights make a funny noise?
A its probably the headlight adjustment motor, they can fail and the noise you hear is them perpetually adjusting, replacement or disconnect and correct setup on a MOT alignment unit are alternatives
Q my paddle wheel is not working properly, it does not change gear on one side properly or it is intermittent?
A Its probably the steering wheel angle sensor failed. It need to go on a diagnostic machine to verify, if this is the case a new steering wheel is the answer
A Its probably the rear shoes and adjusters, if they have not been cleaned or adjusted as per the service schedule or it can be the rear wheel cylinder seals have failed and are weeping brake fluid, a competent garage can remove the rear hubs and clean and inspect the cylinders and replace and adjust as necessary
Q My Car is going very slow like its got no turbo boost?
A Ok 1.first thing to check is under the rear of the car the waste gate arm, its held in place by a tiny E clip and these can rust and fall off, no boost will be allowed at this point, be careful as the exhaust is very hot and you need a clip to be able to fix it.
2. If the car is standard get the car diagnostics checked, it could be the boost pressure sensor, or in the case of remapped cars it could have gone into safe mode (a get you home mode much less power) if you have a high power map and had all the electrics on and air con putting the engine under more load, making it work closer to it maximum boost level.
Q When I accelerate I get a whistling noise that goes up and down with the revs?
A It sounds like the turbo has a damaged inner part, the impellor blades can spin at 2500 times a SECOND and any damage to these special blades will make a whistling noise
Q When I change gear the is a little 'Ptchew' noise I can hear, is something wrong?
A Well If the boost level is increased or a free flowing air filter fitted you will hear this noise, it the sound of the boost in the turbo being released as the throttle is closed, this is normal
Q I have heard dump valves are good on turbo engines, can I fit one to my Smart?
A No, it is not recommended, there is a formula for determining the size of the aperture in the dump valve and most dump valves simply dump too much boost for the smart meaning instead of preventing the turbo 'stalling' (stopping as boost backs up in the system as the throttle is shut) , it dumps too much boost causing the turbo to over speed risking damaging the turbo bearings, most expel oil also causing the engine bay to be covered in an oily film also.
Nb. Brabus Smarts do not have a dump valve fitted and BRABUS did have a car in the Guinness book of records as the fastest 4 door car in the world at 212mph so they know a bit about tuning.
Q My key wont unlock the car is it the battery in the key fob low?
A it could be, more likely the key has lost is coding and will have to be re coded along with the car and any spare keys you might have too.
NB Try to use both keys equally and often. There has been no satisfactory explanation as to why they lose the programming
Q My 42 door handle was stiff and now I cant get in, is this just the cable?
A Its probably the exterior handle, the cable has to make a tight turn inside the door and cable suffers and becomes stiff and finally breaks. A new exterior unit is usually required
Q My Roadster interior door handle does not work, why?
A there is a cable and on the end is a barrel pin that locates in the door mechanism, this works its way out, usually there is nothing broken it can be refitted and secured to reduce the chance of it happening again.
Q My airbag light has come on do I need to worry?
A Yes, usually if the light is on the unit will default to non function. If you have side airbags moving the seat can cause the light to come on the cables are secured under the seat and moving it or putting items under the seat can disturb the wiring.
Q I have a performance exhaust and my engine light has come on, is the exhaust faulty?
A No not necessarily, the smart car has set parameters for all the engines settings, by changing them from standard you run the risk of the engine management unit thinking there is a problem. Changing any part of the car can cause this but exhausts and air filters are most common.
NB. You can buy a unit that fits between the exhaust and lambda sensor that alters the reading reducing the chance of the engine light coming on.
Q My headlight bulbs have gone again is there an easy way to do it myself?
A No, either you have the skill or you don’t, if you try and accidently dislodge the spring clip the headlight has to be removed and the front end will have to come off to replace it and then the headlight need re aligning too.
2. Go to a Smart specialist garage who have experience in doing it.
Q I heard a funny 'TWANG' noise from the front of my car, do I need to worry?
A Yes as the noise could be the top of one of the front coil springs shearing, did you find a inch long piece of black/rusty semi circular metal nearby?
2. The front end suffers all the crashes and bangs you too feel from the cars suspension. The springs seems to rub in the top cup causing damage just as it locates in the top cup, over a period of time this gets worse and one day the spring shears off
Q The heating fan in my 42 only works on full why?
A The resistor is faulty and need replacing, its a simple job and not too costly
Q The heating fan in my roadster is not working, why?
A Most likely it’s the connection to the switch itself, they seem to have a poor connection there and the connection arcs and burns away the metal in the switch unit. It needs repairing, sometimes a piece of wiring loom and connector are required and sometimes the central consol unit will also need to be replaced
Nb this is intended as a guide and as such not a replacement for a trained technician working on any vehicle but a guide to understanding the workings and problem encountered with the Smart in all its guises
Never work under an unsupported vehicle, always use the correct tools and never attempt jobs beyond your training/capabilities. Always disconnect the battery before working around airbags and seat belt housing as both contain explosive devices
