Ask the mechanic: Why Does my car rumble?

Dear Paul, I enjoy reading your motoring articles in the Thursday Monitor. I drive a Volkswagen Touareg. Recently it developed a rumbling sound in the transmission area. This rumbling noise is audible and can even be heard at low speeds of 30 KPH. What could be the cause, I hope my gearbox is not faulty. Raymond.

Hello Raymond, the symptom or noise you describe suggests that your VW Touareg propellor shaft may have a damaged carrier bearing. This fault usually manifests at low speeds such as 30 kilometres per hour. This propeller bearing is located in a centre carrier housing with an attached polyurethane (rubber) mounting. When this bearing kit fails (tears or breaks) the propeller shaft tends to vibrate in response to engine torque as you increase speed on high revs. because of the better centrifugal force. Faster speeds tend to reduce the vibrations. It is important to replace this propeller shaft centre carrier bearing kit because the violent rumbling may lead to propeller shaft and transmission damage.

Hi Paul, can one switch car engines? For example, a Noah engine into a Vitz? Are there any repercussions to switching engines? Stella

Hello Stella, switching car engines from a bigger vehicle like the Toyota Noah to a smaller vehicle like the Toyota Vitz can be done. However, this has limitations and does not always work seamlessly. In Uganda today, there are vehicles whose engines are swapped and fitted with Toyota engines because the original engine parts are not readily available. Modification of the engine suspension, drive shafts, transmission and engine electrical system have to be done to make the new engine work. Switching engines requires some degree of matching in terms of engine fitting (volumetric) and power size, transmission and electrical system. A bigger 2.0 litre (2,000cc) engine will not fit in the engine bay of the smaller Toyota 1.3 litre (1,300cc) Toyota Vitz. The smaller Vitz transmission, electronic wire harness and engine computer will not work on the Noah’s bigger engine. Instead one has to look for an engine that matches the volumetric size and power cubic capacity of the original 2.0 or 1.3 litre engine. The consequences of mismatching car engines often involve poor performance, failure to run or higher costs of correcting the poor job and frustration due to frequent breakdowns.

Hello Paul, thank you for the good work. How do I fix my door lock, my car key takes a while getting out, I am afraid of breaking it, please help.
Bangi

Hello Bangi, my sympathies for your malfunctioning car door lock. It can be frustrating if you are in a hurry and have to fidget endlessly to get the key out of the car door lock. This has happened to me before. When you turn the key in your car door lock, like any other mechanical lock, a set of spring plungers in the lock cylinder barrel, push notches and pins to a predetermined pattern and distance. This pattern is designed to match the one on your key.

Turning the right key in the lock barrel will actuate a lock or unlock sequence. In the event that these lock cylinder pins are damaged, dislodged or worn out due to age they will not read the key easily. The good news is that a good locksmith can replace these pins and restore normal operation. Seldom can the car key fail due to wear and distortion of the key pattern. A good locksmith will be able to read the cylinder lock barrel pattern and cut a replacement key. This key will be able to lock or open the car door lock and be withdrawn without a fuss. Occasionally the door lock barrel system can fail because of intrusion of dust, pieces of lint from the car wash towel, debris or corrosion. This will make it difficult to turn or withdraw they key once inserted in your car door lock. A good ant--corrosion cleaner spray such as WD40 may do trick by releasing the dirt and corrosion.

Ask the mechanic
By Paul Kaganzi
0772316145
send sms: mycar (space) your comments and questions to 6933, or email them to [email protected]