Why should I get 105 degree rated capacitors for my ECU?

Several manufacturers of electrolytic capacitors have confirmed that 105 degree capacitors will last roughly twice as long in any given application as 85 degree rated capacitors. This holds true even if the capacitors are not operated anywhere near their rated temperatures. (Note that capacitors are invariably rated in degrees Celcius, not Farenheit.)

The difference in longevity is directly related to the temperature ratings of the device because 105 degree capacitors must be of much better construction in order to survive at that high a temperature. The highly robust design requirements naturally lead to a longer-lived part. 105 degree capacitors can also survive higher ripple currents, a prime suspect in the premature failures of the factory DSM ECU capacitors.

It must also be noted that each different capacitor series from each different manufacturer usually has a different rated lifespan. Those who have the means should attempt to procure high-temperature, high-reliability capacitors when repairing their ECU.

For those who cannot procure 105 degree rated capacitors, 85 degree capacitors will work. They will simply wear out faster. Those who can practice cap replacement as part of a routine maintenance schedule will certainly be able to utilize 85 degree caps will virtually zero risk of ECU damage.