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I do believe that a few TBs had a teflon-type coating years ago, but I don't think that's a thing nowadays.
Yes the throttle body has a moly coating on it. Per the service manual,
"CAUTION: Do not attempt to clean the throttle body. The bore and the throttle plate has a special coating applied during manufacture which should not be removed."
I cleaned the TB on my 05 Super V8 using throttle body cleaner and it didn't remove the coating. Just don't get aggressive and all will be OK and don't use carb cleaner.
I remember reading somewhere on here that the throttle body plate has a special coating, so you're probably better off not spraying cleaner on it.
Unlike me where I didn't know that and sprayed the stuff directly on the throttle body plate a year ago. Ooops!
I was also at that junction couple decades ago- they said if you clean this TB you will ruin the coating, I said if coating had done its job I would not have to clean it.
Turns out their claims of a lifetime protective coating were unsubstantiated anyway- like those lifetime frying pans.
POSSIBLY see the valve FACES, and that's if you curl the 'scope 180 degrees inside the cylinder. Why look at the valve face? That's not where the carbon builds up. The GDI problem is inside the intake runner, not inside the combustion chamber.
Seeing the condition of a valve face is worthless.
inside intake runner..........
yuk! Once the back of the intake valves get that bad, the only way you’ll get them clean is to have the intakes walnut shell blasted. Having to remove the supercharger will add to the cost. Look up “Dave’s Garage” in YouTube. He has several videos showing this process.
so, why does this happen to GDI engines?
- unlike non direct injected engines, only pure air is passing over the back of the valves.
- non direct injected engines motors have fuel in the mix which keeps gunk from building up on the back of the valves.
- where does the gunk come from? Most of it comes from the EGR system which pumps dirty oily gasses into the intake,
EDIT: I’ve read that ways to reduce build up in a GDI system:
- reroute EGR from intake manifold to a vented catch can. But, I’d expect you’d get smells like an old Chevy. As that forced me to remove the catch can I installed on a Harley.
- use quality detergent oil, which will reduce contaminates in the crankcase gases that go past the intake valves from the EGR system. . And can reduce buildup…behind the valves.
- use top tier gasoline, which reduces carbon in the cylinders, and injectors…not so much behind the valves.
- give it a regular Italian tune up. Higher speed air roaring by the valves will reduce buildup.
I’m very hesitant to put in any cleaner that will go through the supercharger.
