TORONTO, (May 2, 2005) — Heat is said to be creating all sorts of problems under the hood of post-2002 low-emissions engines.

Windshield washer bottles are melting, and there have been reports of air-brake hoses located close to hot parts doing the same. It’s creating problems with seals, wire insulation, and lubricant viscosity too. Seals can expand and leak, lubes become runny and begin to seep past the seals, and wire insulation and wiring looms become brittle, and can even melt in extreme cases.

Hoses too are taking a real beating. Rod Ward, director of sales engineering with hose maker Flexfab LLC, says owners should be taking precautions to protect hoses from the heat by paying careful attention to the routing of the hoses, and by adding shielding and/or insulating wrap where necessary.

“Properly spec’d hoses should last the life of the vehicle, but we’re seeing failures already on some of the first generation EGR-equipped trucks,” Ward says. “The problems with coolant and hydraulic hoses are less obvious because they die from the inside.”

With coolant hoses, watch for a soft, gummy feel to the hose. Thermoset rubber doesn’t melt, it depolymerizes, meaning its strength will be gone. Thermoplastic hose softens with excess heat, and when cool, they will become rubber-like again but will likely be deformed or sagging. Sagging hoses should be replaced.

Drive belts are seen to be cracking and chipping prematurely partly due to excess heat, and partly because of the extra stress created by more frequent fan cycling.

“On/off fan drives, not long ago, were only asked to be on 10 percent of the time for on-highway trucks,” says Vincent Ursini, engine-cooling test manager for Behr America. “Today’s increased need for A/C condenser cooling, charge-air cooling, and ECM temperature management require significantly more fan on-time and increased cycles.”

Even power steering systems are taking a hit. Richard Petrut of R H Sheppard Co. says power steering systems (pumps, reservoirs, and seals) designed for operating temperatures of 140 F to 160 F are now being exposed to temperatures in the 200 F-plus range.

“Our seals are good for 235 F,” he says. “But we’re recording temperatures as high as 230 F in some instances. That’s causing leaks and hose failures.”