Throttle Bodies: “Leaking” is Not a Thing

There is a video that was posted online around 2015 that is still circulating where someone pumps smoke under an unknown amount of pressure into a GoWesty Throttle Body (aka Throttle Valve Housing) and it, of course, bellows out all around the throttle shafts. The makers of this video claimed this was a big problem, that our throttle bodies are junk, and that they do not work. The smoke test visually exaggerated to a great extent that the throttle bodies leak under normal use.

The makers of the video do not reveal how much pressure was being applied, but it clearly looks like way more than it would be when in actual service when the amount pressure present is less than one atmosphere, or 14.7psi—which requires a perfect vacuum to generate, which no engine can achieve. Also, in service, there is vacuum present only on one side throttle plate. So less than half of the shaft and bearings are under vacuum/atmospheric pressure. The pressurized smoke test is a red herring—and not only due to visual exaggeration.

The more important misinformation being promoted here is that any leak around the throttle shaft could make a significant difference in the running of the engine. The fact is that even a fairly significant leak between the throttle shaft and throttle body would be very unlikely/practically impossible to cause any noticeable running issues. The original Volkswagen throttle bodies had no bearings at all, and the shafts would eventually develop all sorts of slop and massive leaks over time. The slop would in fact lead to running issues, but not due to the leaking (non)issue. At the other end of the throttle shaft is the Throttle Position Switch (TPS). When no throttle is applied, the TPS tells the Engine Control Unit (ECU) the engine is at idle so it can kick into “closed-loop idle” mode. At full throttle, it tells the ECU to kick into the “full throttle enrichment” mode. What happens when the throttle body wears out and the throttle shaft gets too wobbly is that it would no longer operate the TPS reliably, and that is what causes the engine running issues. That is why we included ball bearings in our design-so our throttle bodies would pretty much last forever.

So, you are probably thinking to yourself, “Lucas, you titled this article "GoWesty Throttle Bodies: “Leaking” is Not a Thing", but the video clearly shows they do!” We in fact redesigned the throttle shafts and housings to accept o-ring seals and switched to a completely sealed bearing. We did not do this because we changed our minds regarding whether or not the small leak present made any difference. We did it because it was easier to do than making people read articles like this to convince them otherwise!