Butchered repair jobs are only too common, not only at night in some back yard, but also in broad daylight in a big franchised workshop. Most workshop managers of our acquaintance complain that they cannot get good mechanics. Very few young people enter the trade and the older ones are reluctant to get retrained so that they can cope with the new technologies that are coming to the fore.
A sad case turned up the other day. “Snake Eyes” Tshabalala , the local toordokter, recently took his 2001 Volkswagen CitiGolf to a backyard worker, one of his clients, because of low oil pressure. The “mechanic” replaced the oil pump, but when Snake Eyes got the car back he noticed that the oil pressure warning light still came on when the engine was hot.
He then brought the CitiGolf to us. He told me that he had thrown the magic bones, and they had told him that the pump had never been changed and that my garage has the best workshop in the vicinity. He asked me to have the oil pump checked and the low oil pressure problem solved. Hennie started by first removing the sump and then the pump. He examined it and confirmed that it was indeed practically new. He then removed one of the big-end bearing caps, examined the shells and measured the clearance between a con-rod and the relevant crank cheek. The results told him that a bottomend overhaul would be needed soon.
Hennie concluded that the excessive wear negated the effect of fitting a new pump. Japie wanted to know how the engine condition could affect the oil pressure, so Hennie explained that the oil pressure actually delivered at the warning light’s tap-in point is not only determined by what the pump delivers but also by what resistance there is to the flow of oil. This means that if the play in the main- and bigend bearings, as well as the play between the crank cheeks and the con-rod side faces, is excessive, the oil pressure will be much reduced.
Snake Eyes could not really afford the engine overhaul we recommended, but we told him to use the car sparingly until he could. He took the bad news with a roll of the eyes, and a witch’s laugh. We later heard that he raised his fees, and found some more exotic bones and other objects to entice more clientele into coming to him. We hope to see him again soon…