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How many miles can you expect out of a Duramax?

ProScape Canada

LawnSite Member
Ottawa, ON
I was looking in to the 6600 Duramax engine and they seem to go 300-350 but I've seen some hitting 400-500 and one rolling at over 700. The 700 was on a GMC 5500.

lawn king

LawnSite Silver Member
There is one over @ dieselplace with 700,000 + miles on it. Original motor & tranny, still running well. There are many members over there with high mileage on oem motors & injectors!


LawnSite Senior Member
Somewhere in FL
I wouldn't pay that much for it regardless of options. Mine ran PERFECT when I sold it with over 130k on it. It used a little oil, maybe a quart every oil change which was about 8000-9000 miles.


LawnSite Fanatic
Byram, MS
I got a chance to drive it today. The engine and tranny drive like a champ. I had a concern on what the dealer says are the tires. Also the oil pressure sits low when idling warm. I dunno if this is normal on diesels or not. Also I swear the temp guage has got to almost the 210 mark before it settles at the quarter ways mark. I got the guy down to 11000 on price, but I'm still not sure on it yet. As listed on KBB and NADA it is about $6000 less the what the dealer has listed. It looks to of never had a goose neck/fifth wheel in it, so thats a good sign of no real heavy pulling.
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LawnSite Bronze Member
NE Tn.
both duramax's i have had the oil pressure drops when at idle after it's warmed up. comes up fine when accelerating or when running.


LawnSite Bronze Member
Kitchener, ON
TBO is rated at 250K for Duramax V engines, but that's nothing these days for a diesel. Keep in mind you can get a Duramax 7.8L I6 in heavier C and T GM trucks that will more or less outlast the frame.

I had a 6.5L V8 GM diesel in a 3500 extended savanan (with insulated box and reefer on roof) that just turned 1million kms, or 600K miles before I traded it in. The drivers door fell off three hours away, and I never would have expected that which is why I decided to sell it. I'll also add that it would smoke heavily when you pushed the throttle down over 50%, even in low rpms. At around 75% throttle it would downshift and black smoke would be everywhere.