Keep it cool, don't boil over
Page 50
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THERE is absolutely no doubt that the most annoying thing that can happen to an owner-driver is an avoidable boil-up. When this happens you can bet that you have caused yourself a load of problems right at that moment and most certainly in the future as well.
. Once a vehicle engine has been -cooked'', as it is known in the trade, there is a very great chance that it will not be long before the unit develops head problems and /or piston and liner failures as well.
Whatever the cause of the overheating in the first instance, much of the damage is usually done by unwitting action by the driver who may either drive on not knowing that his motor is overheating or because he can't get any water to fill the radiator.
Quite often one sees a vehicle being driven slowly along the hard shoulder, quite obviously in some considerable distress and likely to cost quite large sums of money to put right when eventually — as is certain to happen in the end — the vehicle gives up the ghost in a shimmering haze of unwanted heat.
There are, of course, quite a number of causes for overheating. First we have a lack of coolant, either because the system has sprung a leak or because it has been left too long without being checked and replenished by the handler. Then -there is the failure of the water-circulating pump which, although less frequent in these days of roller or ball-bearings and carbon seals, still unfortunately does happen.
Loose driving belts are yet another cause when both fan and/or water pump speed is reduced because the driving belt is slipping, reducing the efficiency of the driven unit.
On a trip to Workington during the only hot spell we have had during this summer I noticed a very slight rise in my engine temperature, which normally runs just a little above the three-quarter mark on the ungraduated temperature gauge. I first of all made a mental note to check the various items concerned with the system as soon as I arrived at my destination. Watching the gauge carefully, I had ascertained that the rise was not sustained; it had simply gone up by a pre-determined amount and there it was sticking.
On arrival at the delivery point and while awaiting the gang which was to off-load the vehicle, I started to check the points mentioned above. None of the items showed any signs of maladjustment or malfunction and, a bit puzzled, I decided that perhaps the wind had been following me from Kendal and, with the severity of the road, the vehicle was entitled to be running just a bit hotter than usual.
Somewhere in the back of my mind, though, I knew very well that this was not so, for the particular make of vehicle had a considerable air-to-boil margin in its cooling system, and although we had now covered some 210,000 miles together, I had never before seen the gauge go over the above-mentioned position under even the most arduous running conditions.
Running back south unladen, the engine temperature found its normal position and although I was still aware of the situation, the return to normal convinced me that the cause was the following wind. Three or four days later, however, when once more tackling some particularly heavy going in the south Yorkshire area west of Sheffield, there it was again, just a very slight increase over what I knew to be the normal needle position.
When I got back home at the weekend. I decided that I would have a good look round the system, because in my bones I could sense that we would soon arrive at a disaster if the problem were not nailed straight away. So on the Sunday morning up went the cab and I started by having a good poke around the various pipes and joints that make up the system as a whole.
Strangely, though, I could find absolutely nothing that would contribute to any sort of over heating. There were no pipes kinked up,' no loose clips, the coolant came out clean and easy and none of the hoses had any sort of internal deformity that could possibly restrict the circulation of the coolant around the engine.
I checked out the fan drive — that was sound. I checked the belts and pulleys of the water pump drive — they were perfect.
Sitting having a cuppa and wondering what the hell to ( next, I noticed considerable ir erest by a number of small bin around the vehicle, and as I s watching them I noticed pattern of behaviour that ga. me the answer to my ove heating problem straight awa) The sparrows were feedir on hundreds of small insec that had been sucked into tl radiator core by the fan, effe tively reducing the he exchanging capabilities ficiently to cause the rise operating temperature.
Had the cloud of insects be encountered at any sort speed, their mangled carcas, would-have been evident on ti front of the vehicle, but as ti road speed was very low at ti time, probably during one of tl many severe climbs in the Lal District, they were simp sucked into the core.
Ten minutes with the air hr applied to the back of the radi tor expelled the offenders, ar on Monday morning we we back at work with our operatir temperatures back to normal.