L-Jet TPS is all oily, the bottom of the Throttle Body etc.... Options

[malcolm2]

Taking the TB off to be rebuilt and could not help but notice that the under side is covered with oily dirt. 20,000 miles since I put it all together, but this area has, by far, the worst build up.

The boot seems pretty stiff but no obvious cracks of holes.

1. I assume the oil is coming from the oil tower filler neck. But why would it blow out with air sucking in? 1st thought the stiff boot did not make a good seal and this is my vacuum leak. But again shouldn't it suck in? But the btm clamp screw on the boot was very tight.

2. is this normal?

3. are the "S" boots available new?

[Rob-O]

I'll have to look at my seals to verify (or you might be able to find a pic through a search here), but I think that the o-ring fits where you have the flat seal and the flat seal goes at the very top of the cap, where it seals against the oil filler tube. So essentially they look flip flopped on yours. Although that would appear to be hard to do because your flat seal looks too small to fit at the top of the cap.

All that being said, to answer your last question. The center area of the cap is where the crankcase pressure is escaping, up through the center of the cap, past where that spring should be, and back to the intake boot. Think of the oil cap as a PCV. But if that spring is missing, instead of breaking up into a mist any air/oil, the oil has a better chance of just moving up the center of the filler tube, through the center of the cap, Past where the spring should be and into the intake. Also, if the lower of the two gaskets is wrong and not sealing, then oil can just run up the filler tube, past that lower gasket and right into the hose that leads to the intake boot. The design isn't that you seal the cap well and then pressure blows by the gasket. The pressure is coming up through the center of the cap and escaping out of the side of the cap where the spring goes.

So essentially would want to make sure you have the spring in place. You also want to make sure you have the proper lower gasket in place (to stop the oil from getting by). You want the top gasket on to help prevent a vacuum leak.

I probably did a poor job of jumbling up that explanation, but I hope some of this helps!