S65 Throttle Actuator Failures - The Gunk Theory - Give Your Feedback

The theory: Over time oil and gunk buildup on the throttle bodies, particularly around the hinges of the butterfly valves, create a condition where more and more force is required to open the valves eventually leading to throttle actuator failure on BMW S65 engines.



This is similar to theories that suggest a lack of lubrication of the linkage from the TAs to the throttle bodies might be the causation of throttle actuator failure. Provide your feedback, opinions and even photos of your throttle body butterfly valves. Perhaps this theory can be refined, gain support or even be proven false.

If you think the theory has some merit and want some tips on cleaning your S65's throttle bodies, a guide in the DIY section can be found here.

I think you're over thinking this.

It's important to keep the actual linkage lubricated, but going as far and saying the cause could be some dirt on the butterfly is a little much.

My G37 coupe had tons of blow by build up. Cleaned them every 20k but the infiniti ETB's never were prone to breaking so I would say your theory is false.

It's the material BMW uses. I had a Chrysler that needed a new ETB due to the gears shredding.

This theory definitely has merit. I work on HVAC systems where I deal with louvers that open and close. Overtime, dirt accumulates at the pivots making it nearly impossible for the louvers to open/close. Sometimes it binds up so great that it takes 50lbs of force to get it moving again. After, lubrication, the joints move like butter again.

I think the motor electronics fail over time, possibly due to internal gear wear. I suppose this theory would be an explanation for increased internal gear wear. If you want to clean and lubricate, go ahead. Won't hurt anything.

Mythbusters says no.

Mike Benvo wrote

Mythbusters says no.

I'm waiting for Snopes to weigh in.

I think there is an easy answer for this. How many Throttle Actuator failure repeated after Replacement or After Rebuilt? If there is non that means they did not cause this gears to worn. But if it is repeated soon so you re on something!

SaNGRia wrote

I think there is an easy answer for this. How many Throttle Actuator failure repeated after Replacement or After Rebuilt? If there is non that means they did not cause this gears to worn. But if it is repeated soon so you re on something!

Still isn't related. There are plenty of people with high mileage still on original actuators. I'm at 100,000 miles on original actuators.

The simple answer is, these are car parts and they will fail. They don't all fail at the same time. They weren't designed to last the life of the vehicle.

No.

That said, I think engines that are kept clean do run better in the long run. I work hard to keep my engine bay clean, and when you do jobs like spark plugs, it makes sense to spend some extra time cleaning (like the inside of the V... there is always sand and dirt in there).

That's not a thing...

doogee wrote

Still isn't related. There are plenty of people with high mileage still on original actuators. I'm at 100,000 miles on original actuators.

The simple answer is, these are car parts and they will fail. They don't all fail at the same time. They weren't designed to last the life of the vehicle.

You have DCT or MT Doogee? I assume DCT constantly in S4/5 with downshift rev add to the wear? Not that it makes me hold back on this, half the pleasure with the DCT.

Helmsman wrote

You have DCT or MT Doogee? I assume DCT constantly in S4/5 with downshift rev add to the wear? Not that it makes me hold back on this, half the pleasure with the DCT.

Mine is MT. I don't see how there could be much of a difference between the two, if you already rev match.

doogee wrote

Mine is MT. I don't see how there could be much of a difference between the two, if you already rev match.

I was thinking all these quick pull in the plastic gears would add stress, but only guessing out loud. Again doesnt stop me from doing it.

Well, I always push the gas before downshifting. What is the purpose of driving MT s65 for sunday . If this part going to fail, I am ready to stock like 10 of those upgraded gears