Plenum pull scope creep

[evl_twn]

I tested all of the individual lines and fittings with a hand pump brake bleeder with vacuum gauge. Everything under the plenum checked out, so I buttoned up the plenum and put the power plates back in with gaskets above and below. Turns out I didn't need the TB coolant bypass line, the power plates aren't drilled for the coolant passage so it completely eliminates coolant from the plenum and throttle body.

I wanted to check the vacuum pump operation before putting the coolant back in "just in case" . It occurred to me I've never heard the thing run since I've owned the car. I checked voltage at the plug, no issues there. Pulled the pump and found it was locked up. I bought the car from family in FL, it had sat for years in an unconditioned garage so I'm guessing the humidity and lack of use is what did it in. Got a replacement and checked the time between pump runs and it's now holding for 40 seconds between pump cycles.

[evl_twn]

I figured replacing the coolant was going to be a pain without the air bleed path through the plenum/TB. I read Marc's article about lifting up the passenger side of the car, and the revision using air to pressurize the system. Then I saw a few posts and watched a few videos on using a vacuum test/fill kit and bought one. Seems like the best option to me, works exactly like drawing down an AC system before adding refrigerant. Leak checks work the same way.

I purged the system and let it sit for a while, held a solid 25" of hg the whole time. The hoses even collapsed a bit. It was so much easier to add coolant back to the engine, it has a fill line that draws it in using the vacuum created. I think I actually added more coolant than what I drained so it might have been low to begin with, and that's with the lines through the TB still connected so the capacity might be a bit less now.

I was worried a bit about air pockets and bleeding the system but apparently this completely eliminates that issue. When the vacuum came back to "0" and it stopped drawing coolant I removed the tool and found the level was just below the cap. I added maybe half a cup of coolant to bring it up to the top, hooked up the expansion tank line and started it up. Temps seemed perfectly normal, both coolant pipes from the right and left injector housings were equal in temp.

I just got back from the first drive after buttoning everything up and all temps seemed normal. I'll double check the level after everything cools back down and also make sure it draws coolant back up from the expansion tank.

[ZR-1nce removed]

Originally Posted by evl_twn

If the Power Plates actually make a difference and aren't just snake oil, I might be tempted to put them back on (but probably WITH gaskets this time ) but since I already have some scuffs on the hood I wonder if the silicone intake boot Jerry's sells would clear better than the stock one?

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