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Is it normal to have a leak at the throttle body shaft?
I hooked up my smoke machine today, and smoke started coming out of the side of the throttle body, where the shaft goes in. Is this normal? I circled where the leak is:
OP didn't say OIL was leaking, but possibly a vacuum leak detected by a smoke test. Worn shaft or TB bore...
I hooked up the smoke machine to see if there is a vacuum leak. Smoke came from the throttle body shaft. I didn't see smoke from anywhere else. It is a Nick Williams 102mm throttle body.
I found another thread from a while back where Nick Williams chimed in, and said that this is normal. I also talked to a couple of reputable people locally, and they agree that a small leak at the shaft housing is normal.
If it has double seals, no seals, whatever; how bout getting a 2RS bearing variant for it? (double rubber seals)
Check out bocabearings.com for a dizzyingly yyyyuuuuuuujjjjjje catalog of bearings in that general overall size range. (i.e. 608 size for example) Throttle shaft bearings are roughly the same size as skate bearings, shouldn't be ANY trouble to find any/every imaginable config detail of them. Just went to a skate store the other day to get bearings for a window AC unit; bearings are bearings, they don't too much care what's all around the bore and the shaft. (hehehehehe) Not even if there's some hair.
Maybe Nick Williams, or someone familiar with the assembly of one of his throttle bodies will chime in here. I tried to e-mail him through LS1Tech, but that was only a couple of days ago.
For now, I am going to leave it alone. I don't want to tear the throttle body apart, and end up with a car that I can't even drive to work.
I recently bought a Fi Tech 92MM throttle body and BRAND NEW right out of the box it was leaking at that exact location, AND there was no O-ring under the TPS so it too was leaking at the OTHER end of the shaft. I replaced the O-ring, and smoke tested again and it was STILL leaking at the shaft like yours is... That is the downside of after-market JUNK. You can put your factory TB on and test it-it will NOT leak.. I tested my factory truck 78mm unit that had almost 300,000 miles on it and it does not leak. I destroyed the Fi Tech throttle body attempting to cut an O-ring groove in the throttle blade shaft that would have sealed to the aluminum bore in the TB housing. My loss.. Zero miles on.. just under $200 for a brand new part that was TRASH right out of the box. I should have just returned it when it failed the smoke test. If that leak is small enough, it *might* be okay. Otherwise, if you are MAF less it won't really matter. For those who are running a MAF... It's unmetered/unmeasured air getting into the engine. Small enough amount won't matter.. it will be leaking MORE at idle where airflow calculations are critical-and less as the throttle blade is opened. But if it's leaking now.. How much will it be leaking in another 20,000 miles?
If it's new I would return it. If it is used.....and you can't return it... I don't know.... Why were you smoke testing the engine in the first place? Were you looking for a vacuum leak?
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Is it normal to have a leak at the throttle body shaft? 
