Is it true that GMC motors tend to start going bad after about 100,000 miles?

Question

I'm thinking of buying this 99 sierra, but wanted to know how dependable the motor is. the owner(my friend) said all th eproper maintenance was done on time.

Answer 1

VD, I have friends and co- workers that drive GM made vehicles that have well over 200,000 + mi on them I , personally have put 247,000 on a 1989 Olds ,231,000 mi on a 1982 Chev Malibu, and currently have one Eldorado with128,000 mi on it. Since I ,and my co-workers are GM gypsies and have been transferred around to where it wasn't unusual for us to be driving 150-220 mi round trip to and from work. One friend of mine has a GMC pick-up with 350,000 = mi on it(that was 4 mo ago) so I don't know how much he has now on the truck. Yea, any car Co. back before fuel injection and overdrive tranny's did have a problem just getting to a 100,000 mi,. So with the exception of water pumps,fuel pumps,altenators, some sensors you are good for a lot more mi .unless the vehicle was very badly mistreated,the fluids not changed . The REAL QUESTION IS HOW LONG YOU KNOWN THIS FRIEND AND HOW WELL?

Answer 2

I have a 93 GMC Jimmy with 188k on it. Most GM v8s if maintained properly will last well beyond 100k. Their v6 engines with the exception of the 4.3 aren't quite as good. If this 99 Sierra has the 4.3 or any of the v8s then you should be good. Just make sure that all of the maintenance has been kept up with and the motor sounds good. Overall though I have found that I prefer GM trucks to all others. In case anyone wonders my dad was a mechanic for 20 years and I work for an auto auction and deal with these cars on a daily basis.

Answer 3

Sadly only Rover seem to be able to make camshafts that last, apart from the V8s they are fine to 300 000 miles, General Motors have not got he hang of this even now and while they keep going they are badly down on power after about 70 000, really bad by 100 000, If there is a service history and every oil change has been done on time it may be OK but expect to buy a new standard Cam if you want performance. That is why performance cams transform the power of old engines, the wear on the old cam, a new stock cam will give almost as much power and Idle and not wreck the Gas mileage.like a performance item.

Answer 4

No! Not true. As with anything mechanical, it starts going bad the instant it is first started. The key to longevity is not how many miles, but how well it is taken care of. Some people can buy a car with 200,000 miles on it and drive it forever, some can buy one new and it is used up a 50,-60,000 miles. It is a judgement call on your part and only you can make that decision.

Answer 5

Generally, speaking-- I know this is true of Chevy, so it should apply to GMC (they're the same vehicle). For a vehicle of that era, you are not likely to get much more than 100 K out of it.. and expect the transmission to go already. In fact, by 100 K, I would expect that there has already been major tranny work done.

Personally, I wouldn't touch it.

Answer 6

100,000 miles is a lot of miles for any engine to take. If you give the engine oil changes at least once a year, per from other maintenance and are not too hard on the engine (your not racing the car) it should last a lot longer than 100,000 miles.

Answer 7

Through the '80s and '90s GM had some sever reliability problems which is where you are getting this rumor from. Their current crop (last 3 years or so) are much improved over the old stuff. They should last over 150k no prob. As long as you maintain the engine once in a while.

Answer 8

As they have said it all depends on the maintaince of the vechical. I personaly have a 1984 GMC s-15 with about 200000 on it and it still is doing fine, not like brand new but still starts evertime and has never left me walking.

Answer 9

i think that there are lemons in every car company my parents in law have a Holden commodore and it has done 250 thousand miles and it hasn't missed a beat i have a Holden commodore and it has done 100 thousand mile and it hasn't missed a beat so i am not sure about gmc motors going bad after 100 miles

Answer 10

Depends on how the motor is maintained and driven.Look after it and service it at scheduled service times.Be sensible,friend or no friend, to be on the safe side , have it checked by a certified mechanic.