Hello, I'm interested in buying an h1, between a 98-2001. I want to eventually do the duramax convention but in the mean time I want it as my daily driver. I drive about 1200 miles a month and what really has me worried is the overheating. What is the max mph and for how long can I go at a certain speed. I know hummer is not about speed but I wouldn't like to pop anything. Any suggestions?

 

The 98-2001 model years used the same engine and the torque/HP ratings were the same. 2001 had the GEP heavy block and was not prone to the #8 cylinder issue though. A comfortable highway cruising speed is 65-68 mph. They will cruise at 75 mph but I wouldn't recommend it. Usually at that speed your T-case and transmission temps start getting pretty high. Also when you are going up steep or long gradual inclines you may have to reduce speed to keep your engine temps in a comfortable range. I generally try to keep my engine temps below 215 degrees even though AMG says that you can operate them normally up to 235-240 degrees. I would install a Scanguage to more accurately monitor the temps because the OEM gauges aren't particularly accurate.