What's the temperature of the air when compressed in a diesel engine? Home > FAQs > Diesel Engines Search RV-Coach Online What's the temperature of the air when compressed in a diesel engine? The temperature of the air when compressed is at between 800 and 1,000 degrees (fahrenheit). This does depend, though, on the compression. Advertise HereGet Media Kit NOW! Advertiser Links Just Montessori Curriculum