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The Effects of Heat on a Vehicle’s Engine and Transmission

Summertime and the livin' is easy! Yes it might be for people, but what about vehicles? Let's explore what heat does to a car.

Today car manufacturers must build cars under strict controls defined by the EPA standards, which require better fuel efficiency and lower exhaust emissions. One significant way they have complied is by manufacturing engines with more aluminum, which is much lighter than the material of old -- cast iron. This lowers the vehicle's overall weight, thus decreasing fuel consumption. That's the good news. The bad news is that aluminum has a lower melting point than the cast iron, so it is not as forgiving when it comes to heat. The catch is that in order to achieve the low exhaust emissions required, the engine must run at high temperatures! Factor into the equation the high temperatures of summer with the possibility of a coolant leak and you have -- engine meltdown!!

Equation # 1:

Aluminum + high temperatures + coolant leak = ENGINE MELTDOWN!!

The transmission also operates under tremendous heat. Many of the internal parts are referred to as "soft parts." The soft parts inside the transmission are made up of the rubber seals and clutches (which are made of a soft friction material much like brake shoes and pads). The transmission oil is cooled by a transmission oil cooler located either in, or affixed to, the car's radiator. Overheat the transmission and ugly things start to happen. How does a transmission overheat? A couple of ways:

  • Neglecting scheduled services: The transmission should be serviced every 25-30 thousand miles (recommended intervals vary by manufacturer). Service means changing the transmission fluid and filter. The transmission develops wear material (which is normal, by the way) that is caught in the filter. As the filter fills with this material, the flow of fluid (or oil) slows down. This, in turn, causes the transmission to heat up, breaking down (viscosity breakdown) the fluid's ability to lubricate and cool. The overall effect is an increase in friction and heat, wearing out the transmission prematurely.

  • Overworking the transmission without adequate cooling ability: This happens quite often as well. How many times have you seen a car or truck pulling a boat larger than itself during the summer months -- with the outside temperature exceeding 90 degrees?

    Here's what happens in this scenario. The transmission heats up from overwork because it isn't designed to pull this kind of a load. If you intend to haul trailers and large loads, get a vehicle with a towing package, will ya?!!! Next, the fluid starts being pumped through the system faster than it can get cooled. Friction and heat build up and (as Emeril Lagasse' says) BAM!!!!! The transmission is history. The best way to avoid this is to get a auxiliary transmission oil cooler installed. Oh, and don't pull something that is four times your size and weight!

    Equation #2:

    Poor transmission maintenance + poor transmission
    cooling + excessive towing load = FRIED TRANSMISSION

    In conclusion: Remember, aluminum is unforgiving when it comes to heat. Have your car's cooling system checked every six months. A proper cooling system analysis consists of:

    • Cooling system pressure test including the radiator cap. Repair any leaks.

    • Antifreeze protection test

    • Check the condition of the hoses and belts. Replace any soft or brittle hoses and cracked belts. Tighten all loose hose connections.

    • Flow test, making sure that proper coolant flow and temperature are evident. Once again, repair anything that needs repairing.

    Keep your transmission in good health this summer by:

    • Performing the manufacturer's suggested scheduled maintenance consisting of fluid and filter changes. Rule of thumb: every 25-30 thousand miles.

    • Don't overwork the transmission by overloading the car with a ridiculously heavy load.

    • When hauling a trailer or carrying extra weight, have an auxiliary transmission oil cooler installed.

    Following these suggested maintenance habits should help realize trouble-free driving during the summer months. Now get out there and have some fun!

The Effects of Heat on a Vehicle's Engine and Transmission

Summertime and the livin' is easy! Yes it might be for people, but what about vehicles? Let's explore what heat does to a car.

Today car manufacturers must build cars under strict controls defined by the EPA standards, which require better fuel efficiency and lower exhaust emissions. One significant way they have complied is by manufacturing engines with more aluminum, which is much lighter than the material of old -- cast iron. This lowers the vehicle's overall weight, thus decreasing fuel consumption. That's the good news. The bad news is that aluminum has a lower melting point than the cast iron, so it is not as forgiving when it comes to heat. The catch is that in order to achieve the low exhaust emissions required, the engine must run at high temperatures! Factor into the equation the high temperatures of summer with the possibility of a coolant leak and you have -- engine meltdown!!

Equation # 1:

Aluminum + high temperatures + coolant leak = ENGINE MELTDOWN!!

The transmission also operates under tremendous heat. Many of the internal parts are referred to as "soft parts." The soft parts inside the transmission are made up of the rubber seals and clutches (which are made of a soft friction material much like brake shoes and pads). The transmission oil is cooled by a transmission oil cooler located either in, or affixed to, the car's radiator. Overheat the transmission and ugly things start to happen. How does a transmission overheat? A couple of ways:

  • Neglecting scheduled services: The transmission should be serviced every 25-30 thousand miles (recommended intervals vary by manufacturer). Service means changing the transmission fluid and filter. The transmission develops wear material (which is normal, by the way) that is caught in the filter. As the filter fills with this material, the flow of fluid (or oil) slows down. This, in turn, causes the transmission to heat up, breaking down (viscosity breakdown) the fluid's ability to lubricate and cool. The overall effect is an increase in friction and heat, wearing out the transmission prematurely.

  • Overworking the transmission without adequate cooling ability: This happens quite often as well. How many times have you seen a car or truck pulling a boat larger than itself during the summer months -- with the outside temperature exceeding 90 degrees?

    Here's what happens in this scenario. The transmission heats up from overwork because it isn't designed to pull this kind of a load. If you intend to haul trailers and large loads, get a vehicle with a towing package, will ya?!!! Next, the fluid starts being pumped through the system faster than it can get cooled. Friction and heat build up and (as Emeril Lagasse' says) BAM!!!!! The transmission is history. The best way to avoid this is to get a auxiliary transmission oil cooler installed. Oh, and don't pull something that is four times your size and weight!

    Equation #2:

    Poor transmission maintenance + poor transmission
    cooling + excessive towing load = FRIED TRANSMISSION

    In conclusion: Remember, aluminum is unforgiving when it comes to heat. Have your car's cooling system checked every six months. A proper cooling system analysis consists of:

    • Cooling system pressure test including the radiator cap. Repair any leaks.

    • Antifreeze protection test

    • Check the condition of the hoses and belts. Replace any soft or brittle hoses and cracked belts. Tighten all loose hose connections.

    • Flow test, making sure that proper coolant flow and temperature are evident. Once again, repair anything that needs repairing.

    Keep your transmission in good health this summer by:

    • Performing the manufacturer's suggested scheduled maintenance consisting of fluid and filter changes. Rule of thumb: every 25-30 thousand miles.

    • Don't overwork the transmission by overloading the car with a ridiculously heavy load.

    • When hauling a trailer or carrying extra weight, have an auxiliary transmission oil cooler installed.

    Following these suggested maintenance habits should help realize trouble-free driving during the summer months. Now get out there and have some fun!