Hi, I have a 2006 Hummer H3 (which I love)! I can't believe that GM stopped making these things...but anyway, that's not what this thread is about (sorry for my rant).

My 2006 H3 has about 76,000 miles and has never had a tune up. I keep asking the Cadillac dealership if I should have them change the plugs and tune the engine, but they say NO. They've advised me that I don't need a tune up until the engine is 100,000 old. However, we're on 8 years now...and I'm getting concerned.

What advice would you give me regarding the plugs and a tune up?

I plan to change the timing serpentine soon, because I want to use it more on the highway and I was thinking that maybe I should go ahead and do the plugs and a tune up as well -- your thoughts?

Thanks,
Fulano

 

is it running rough? The owners manual breaks down the maintenance requirements...

http://schwarttzy.com/wp-content/upl...ers-Manual.pdf

MX requirements start on page 426

 

You are driving a computer controlled distributor-less electronic coil on plug pack ignition vehicle, timing is not controlled through a belt or mechanical means. There is no "tune up" to do.

If it ain't broke, do not fix it. Search how to check the belt for wear, I always have a spare on board.

Plugs should go 100K miles and some knuckleheads have went well beyond that.

Basically if your idle is good, and it is running smooth, kick back and enjoy what the vehicle was designed to do.

You did not mention having cleaned the TB or MAF. If you have not done that, search it out and invest the $$ in the TB and MAF cleaner sprays, and do that if you feel you just gotta do something.

The basic what to do if my 3 runs rough thread is in the FAQ section. https://www.hummerforums.com/forum/h...what-do-33916/

 

My mechanic, I've known for several years, suggested l change my plugs on my 2006 H3. He said the plugs can be tough to remove and doesn't suggest leaving them in for 100,000 miles. He says age of the vehicle should also be considered. Had the throttle body and maf sensor cleaned and plugs changed march 2014 at 80,000. Runs like new now. It was running rough while slowing down to a stop.

 

"Tough to remove"?????

The I5s are the easiest vehicle I know of, next to maybe single cylinder lawn mower, to change the plugs out. They are all on top of the motor without obstruction after removing the intake. You need only three tools and 20 minutes (two of those are to get the intake out of the way). If he was serious, I would not be relying upon his advice anytime ever.

 

So Doc there is no issues leaving them in for 100,000 miles or several years in that engine. That's good to know. The mechanic said in that engine the plugs are sometimes tough to remove because they get stuck and takes extra effort or expense getting them out. So he was wrong.

 

Very good posts Doc Olds. I'll look into the TB and MAF. My H3 is running about 95% smooth. I have a very, slight rough idle, but I've always attributed that to the fact that its an I5 and it never going to be 100% smooth like my wife's Mercedes-Benz.

I'll also check out your posting.

Thank you very much!!!
Fulano