Why does my surf vibrate when I cold-start it?

Before yoi a long distance drive, some checks are important. FILE PHOTO

Hi Paul, How best are Yana tyres on small cars like Toyota Limited size 165x13? Bbosa

Hello Mr Bbosa, before buying Yana tyres or any other brand of new tyres on the market there are important considerations you must make. Tyres play an important role in maximising traction, control and safety of vehicles on the road. You need to consult professional tyre dealers but you must know some basics about tyres in order to ask the right questions. Tyre sizes considered must fit on the wheels and wheel well area when you steer. Tyre sizes such as P195/65R15 are displayed on the car by all manufacturers. A tyre size is determined after rigorous testing. For instance, 195 is the section width, 65 the percentage of aspect ratio of tyre height and width. 15 is the wheel (rim) size. The tyres must have a tread design and compounds suitable for your road terrain and climate (a mixed tyre tread design suitable for summer climate). Tread designs suitable for only road driving will wear out fast because we often drive on murram roads in the suburbs or the villages once in a while. A good tread design will quickly evacuate heat when you drive fast and water when you drive through rain. Tyres have important information such as the date of manufacture, tyre load and speed rating and the purpose ie P- passenger. So you need to consider all these before settling for a specific type of tyre.

Hello Paul, I appreciate the advice you offer on vehicles, I am an ardent reader of your column. I am planning on purchasing a super custom or super gl (plus fitting in tourist chairs and interior) for my newly-started travel company and child drop off services. Please, compare the two vehicles on the basis of fuel consumption, initial cost, maintenance, durability, among other issues.
Woofy Mathew.

Hi Woofy, the Hiace Super GL (Grand Large) and Super Custom (built to customised specs) are different in terms of interior accessories, space and comfort amenities. In your case, you are probably planning to remove the original eight seats and replace them with the 10-14 seats for the tourist conversion. Different Toyota Hiace generations and Editions will change shape such as the Regius, Granvia etc. Engine performance and fuel economy differs according to size and generation. There are three common Hiace engine types and here are their fuel economy and performance statistics. The more popular and easier to maintain 2.8 litre (2,779CC) turbo diesel 3L delivers the smallest engine power 91 HP (horse power) at 4,000rpm but the best fuel economy of 13KM/L. The 2.4L turbo diesel delivers a higher 97 HP at 3,800rpm but less fuel economy of 11.1KM/L. The more costly to maintain 3.0 L turbo diesel 1KZ-TE delivers more power 130HP at 3,600rpm and the worst fuel economy of 10KM/L. However, some buyers overlook the fuel economy difference and buy this engine because of its excellent pulling power and torque, especially when fully loaded with passengers and driving uphill to places like Kabale.

What causes an engine backfire?
Paul Cherotich

Do you mean engine detonations? These are explosive sounds usually caused by an engine misfire. An engine misfire happens when one or more of the cylinders in an engine does not fire correctly. It is caused by an interruption of the air-to-fuel ratio inside the engine. This can be a result of fuel starvation (dirty fuel filter or damaged fuel pump) or restriction of intake air supply. Seldom, it may be a result of an engine vacuum leak.

Dear Paul,
I bought a Toyota Hilux surf model 1998 online in 2013.
It was 199,000 kms on its clock but it was perfect. I have driven it for 20,000 kms now and these days when I cold start it and engage the drive or reverse gear, it vibrates in the transmission. What could be the cause of the vibration?
Nsubuga Francis

Hello Francis, vibrations are usually caused by rotating assemblies that are either loose, damaged or not properly harnessed by their suspension. These vibrations have to be investigated without delay. In your situation, the vibration in your transmission could be caused by damaged transmission mountings or worn out propeller shaft mountings or bearings. Any good mechanic should be able to figure out the cause after observing these two components with the car raised on a ramp or over the inspection pit. At a mileage of over 200,000 kms it makes sense to check the condition of all mountings, suspension bushes and shock absorbers. I would use this opportunity to check or change your timing belt too if your engine does not have a timing chain.

Ask the mechanic >
By Paul Kaganzi
0772316145
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