Cadillac Tech Tips - How to fix it Discussion, Cleaning your engine of evil carbon in Item Specific Cadillac Discussion; The PCV tube runs right across the front valve cover. There might be a beauty cover on top to remove ...
The PCV tube runs right across the front valve cover. There might be a beauty cover on top to remove first (mine has always been missing lol). The PCV valve is on the right side (saying all this looking under the hood, not from the driver perspective). The tube comes out of the throttle body on the left side of it, towards the front a bit, and it's larger than the other vacuum tubes on that side.
I would say it's similar to the carb cleaner procedure you performed...except that stuff isn't nearly as robust as GM TEC. Seafoam might be another story. I personally pour the GM TEC right into the throttle body blades, while holding the throttle slightly open as necessary. This makes it easier to pour it in at a controlled rate (or so has been my experience judging from the engine behavior). I also noticed by doing this, it acted as carb cleaner only much better, and from what I can see, it nailed the intake manifold as well. Carb Cleaner is good to hit your EGR tubes with though...and I also pour some GM TEC down in there and let it soak so the EGR passageways get a good cleaning. Just always be conscious of that hydrolock issue.
If I were to pour TEC into the throttle body to clean the engine, should the car be idling or off? If it's all the same, should I run the engine to 2000rpm and follow all of the other procedures drawn out for the PCV method? Would it be more effective to spray TEC into the PCV or to pour it into the TB (or no different)?
Don't worry, if you don't know something, the only way to find out is to ask.
The engine should be running... Yes, the rest of the procedure should be the same as has been mentioned on here.
Pouring it in via the throttle body is just something I did...It might be mentioned before on here, but I haven't seen it. The reason I say it's more controlled is the PCV will take it right in past the blades, which is why you have to be even more careful about pouring it in slowly. It's also just physically easier than getting it into a vacuum hose. I hold the throttle arm just slightly so it revs a wee bit. That way, I can pour a little more without stalling it. The only time the engine should be off when doing this is letting it soak after it stalls or you turn it off for that purpose.
The reason you don't want to pour too fast is hydrolocking the engine. On the intake stroke, the intake valve opens, and it sucks in air, and if you're pouring it in, GM TEC or whatever... Then both valves close, and the compression stroke occurs. If there's too much liquid in the combustion chamber at this time, it will try to compress the air/fuel mix and because liquids don't really compress, it will be unable to do so, and that can cause some nasty engine damage. Instructions indicate you can pour most of it in...then pour the rest in just enough to stall it... That way, it cooks the carbon off as it sits in there. I've always chickened out on actually stalling it lol..but that's what I meant by be aware of hydrolocking whenever you're introducing any liquid into the engine.