In continuation of last month's blog entry, I want to continue to expound on the summer and heat implications that are in store for commercial equipment.

This second segment deals with ambient and under-hood temperatures - a very important factor that disables units on the road.

A. Excessive under-hood heat generation is becoming a more serious issue than many people realize. I have discussed this very topic with many fleet managers and they have all witnessed first hand how excessive heat is literally shortening the life of belts, hoses, fittings, wiring harnesses, gaskets, seals and a host of other items. With reasons ranging from engine noise (DB) to environmental concerns, everyone understands why the engine compartment continues to be engineered in a more encapsulated and sealed design. Unfortunately, this approach is also creating premature failures in the above components.

The other side of this coin is that in the old days, a technician could easily perform routine maintenance and repairs without removing a multitude of panels and covers. Today, access to the engines is definitely a labor intensive chore that takes additional time and technique to simply get at the components that require attention.

One fleet manager told me that it takes his technicians 15-20 minutes just to remove the panels and covers to begin work on his engines. Another fleet manager told me he had to cut vent holes in his fiberglass hood assembly to allow more ram air to help maintain acceptable temperatures under the hood. Yet another stated he is losing turbocharger seals and bearings due to excessive heat and an inability to disperse the over heated compartment air.

The introduction of compound turbo charging will obviously help the economy of today's engines, but what affect is this going to have on the already over-heated engine bay?

B. High ambient heat is simply a fact of everyday life during the summer months and I see many "coolant leaks", "hose failures", and "over-heating" issues each and every day. There is no miracle cure for these failures other than a good preventative maintenance program that addresses hose routing, hose chaffing, clamp integrity, and often overlooked age deterioration.

I am a staunch proponent of the silicone hose, but even the best hose won't survive a long hot summer if it is not routed and clamped properly. Heater hoses, fuel heater hoses, etc. should all be considered suspect when your technicians conduct their periodic inspections. Remember, due to the expansion and contraction of the connection neck material, clamps loosen on their own. Without routine inspections, this multiple coolant leaks will result.

The radiator cap is another important component to keep an eye on. Do you have the properly rated pressure cap recommended by your engine manufacture? Have you recently inspected your fleet's radiator cap gaskets for signs of deterioration?

Thermostats will fail at the least expected time and pressure testing of your cooling system should be done at each and every P.M. inspection.

Last but not least is the many condensers that are mounted in front of your main source of cooling - the radiator. Are these condensers kept clean from debris and checked for fin damage? The radiator, mounted behind the other condensers, must be maintained to a high degree of cleanliness, internally and externally and kept free from fin damage. The proper type and amount of antifreeze and SCA is just as important for summer/heat driving as it is for winter/cold conditions.

There are many more items that heat can have a detrimental affect on, rendering your equipment immobile on the side of the road. As I've stated many times before, your best defense lies in the integrity of your routine inspection procedures.