Throttle Body Service... WTF? Over!

[ssstealth]

So I take the beast in for the 50,000 mile service that OnStar keeps harassing me about. This consists of a transmission fluid flush and a throttle body service. The dealer does the transmission service but tells me that they are not willing to service the throttle body because the supercharger must be removed to get to it. I take their word for it and drive the car home.



Later, I open my 33,000 bible page service manual and look up throttle body. It states very clearly on page 6-2851 that the supercharger does not have to be removed to replace, let alone service the throttle body...

However, they do ask that you remove:

• Left and Right engine sheilds
• Shock Tower Brace
• Power Steering Cap
• Oil Filler Cap
• Engine Cover
• Air Cleaner Duct
• PCV Hose from SC Duct
• Front SC Ductwork
• Hood
• Windsheild Wiper Arms
• Air Inlet Grille Panel
• Windshield Wiper Motor
• Air Inlet Housing Panel
• EVAP Line Fitting and Line
• Brake Booster Hose
• Rear SC Ductwork

Then after all that they say to use a mirror to inspect the housing for deposits. This is to be done every 25,000 miles? PLEASE tell me that you have found a better way!!!

[V-Eight]

Damn, that is pretty ridiculous.

[leija_01]

R&d ftw.

[ewill3rd]

Yeah you have to remove all kinds of crap to get to the throttle body. It is under the supercharger on the back side and you do have to remove a lot of that stuff but not the hood.
You can disconnect it and prop it up higher for more room.
As far as cleaning the throttle body, I would probably wait until maybe 100,000 miles and even then you have to trust the guy doing it. It is easy to mess up the boots and or ductwork if you are not careful.
It will be subject to carbon buildup but on a supercharged car it should be much less due to the way the intake is set up. The older drive by wire throttles were more sensitive to coking than these new ones are.

[CIWS]

Originally Posted by ewill3rd

As far as cleaning the throttle body, I would probably wait until maybe 100,000 miles and even then you have to trust the guy doing it. It is easy to mess up the boots and or ductwork if you are not careful.
It will be subject to carbon buildup but on a supercharged car it should be much less due to the way the intake is set up. The older drive by wire throttles were more sensitive to coking than these new ones are.

Thanks for the added input ewill. My dealership shows this at the 30,000 mileage mark (wonder why they don't agree ) and to be honest with the lack of knowledge they have demonstrated with this car I was really concerned about allowing it. Seems like waiting for this particular item will be best.

[WillySTS]

That was a "weak suck" dealer that told you they would rather not do it, I would never tell you that,...but...it's gonna cost you(compared to other throttle body jobs).

Different dealer do follow different service menus for whatever reason, I think it has to do with whatever the market will bear in that area or in Kali, whatever is "trendy". I personally have cleaned the throttle body on 2 of my cars that had one after I inspected it and didn't like what I saw.On both of these car I did it once during the whole time I had it(5 years on one 8 years on the other). I have not done it on my V, but I will inspect it at 50,000. Oh, slight correction to the facts...make that 3 vehicles...I did it on my current pickup, a 2003 Silverado 5.3, because I inspected it right after I bought it well used, it looked like it had been cleaned but I cleaned it anyway...169,000 miles...what the heck.

[inurok]

Wow seems like alot of work either way. I guess I am kinda glad I have a long ways to go before dealing with that headache.

[inurok]

What major changes did they make to the 2008 model STS? I have the GM service manual set from a 2008 and it 5 phone book sized manuals. Did they do enough changes to warrant 2 more huge volumes?

[ewill3rd]

The new manuals are basically a computer printout of everything we have to sort through.
I think the issue is that you have 4 engine choices and a couple of transmission choices.
(I forget did they offer DI for '08?)
They have separate sections for each engine and transmission.
Most of the other stuff is the same.
I haven't used a paper manual in about 4 years, it is too hard to find the information in them and the online stuff we use is so much easier.

[inurok]

You are right the DI engine was added in 2008 but i would assume the non DI engine info would have been removed since that engine was no longer standard?

[ewill3rd]

If it is available (and I am sure it is) then it will be in there with it's own sections.
Remember the manual is for any car built for that year with that body.

[ssstealth]

I think the dealer could have investigated a little more, but I am glad thay did not just go ahead and take half the car apart and charge me $$$ for an unnecessary fix. My 2006 owners manual on page 6-6 states to do this every 25,000 miles.

Now, I know exactly how it feels on the Chevy truck when the throttle body starts to gum up. You can no longer gently push the throttle. There is resistance for a while then BANG... you lurch forward when the plates break loose. A rag with cleaner and 5 minutes tops and it is solved.

QUESTION: Since this car is throttle by wire, would a sticky throttle body act the same? Certainly easier to feel it with the foot tham to dissasemble the car.

[ewill3rd]

I haven't seen any of these stick like the ones you are talking about sss. I used to see that problem a lot with the cable TB assemblies on the trucks. The early drive by wire ones had issues with stumbling and stalling due to airflow issues created by the carbon buildup. These new guys seem to handle all that much better. I think they have been learning as we have moved forward.

You could do it as often as you'd like but I am telling you it sucks to get to the darn thing.