No, there is no change in temperature when moving the dial up or down, or on max heat. I have noticed to it almost seems like there is no change when I switch it over to economy... but that could just be my head.

It's odd that you suspect the motor mounts. The previous owner, a friend had told me he replaced the motor mounts on this vehicle... None the less it still doesn't take away from the issues when shifting.

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1986 300E W124- 93,000

“No nation ever taxed itself into prosperity.”- Rush Limbaugh