348 Coolant Leak under Plenum

Hello everyone, I had a leak under the plenum, and located the issue. Here is a how-to if anyone else runs into this issue. I have to give Ernie 100% of the credit, as he already has a thread on how to remove the plenum (but his was for a different reason). You can find his thread here, which is what I followed when I did mine:

https://www.ferrarichat.com/forum/threads/348-fuel-injector-intake-plenum-removal.305475/

So, once again, Ernie, Mr. 348 himself, deserves all the credit for this thread I am about to post.

Ok, let's get started

 

The very first thing you must do is disconnect the battery - DO NOT DO THIS WITH BATTERY CONNECTED (I can hear Ernie chuckling as he reads this )

 

Disconnect Idle Air Control Valves on each side of the plenum. Unscrew the clamps fastened to the plenum, remove the retaining clamp holding it.


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Next disconect Throttle Position Sensor on each side


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Next disconnect Mas Air Flow sensor on each side


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Next loosen the clamp on the intake tube on each side

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Next remove the intake ducting/tubing on both sides
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Next loosen the clamp holding the Secondary Air Injection tubes on the bottom front of the air box, then remove the tubes.
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Next remove the 4 nuts holding the air box in place.
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Next remove the remove the Throttle Position Sensor wires from their clamps, because now we are going to remove the intake tube off. Do this for each side
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Once that's is done, you simply pull the air box back out of the way. Or, if you're like Ernie and like a lot of space to work with everything out of the way, you can disconnect a few more tubs/hoses and then completely remove it from the engine bay and set it aside. In my case, I kept everything intact and just pulled it to the back of the engine bay and out of the way. Whichever way you want to do it, it works both ways.
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Next we need to disconnect the fuel line from the clamp holding it in place. Need to do this so that you can access the clips on the injectors.
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Next, with the fuel line out of the way, go behind the fuel rail harness and unclip the injectors. Just gotta push up on it, it is clipped in on one side (clip on the bottom, so you will be pushing up with the your finger).

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Next remove the allen bolts that hold the fuel rail to the plenum. There are 4 total, 2 each side, one front and one back. These allen bolts are made of soft material, mine are still OEM and I haven't gotten around to changing them yet. Ernie and a few others have already changed theirs out.
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Next remove the throttle linkage located at the back of the plenum, right in the middle. This was easy, no tools needed, just push it down to loosen and get slack, then simply slide it up and off.
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Next, remove these two cables on each side. I have no idea what these are, but they are fastened to the valve covers. Ernie didn't have to do this in his thread, so it was new to me. I have a 1993 SS, Ernie's an previous model, so maybe this was an addition to the later models. In any case, minor part of the job, quick and easy.
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At this point you can double, triple, and quadruple check that everything is disconnected. Grab the fuel rail line and pull it out. Gently of course, may have to wiggle to get it out. I had to borrow these pictures from Ernie as I forgot to take a pic her.
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Next disconnect the injector harness, twist it counter-clockwise (lefty loosey, righty tighty )
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Next remove the nuts holding the wiring loom in place. Need to get these out of the way so we can reach inside and unclip the Coolant Temperature Sensors.
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Now we have room and access to the Coolant Temperature Sensors. Like the clips on the fuel rail harness, it is only on one side. I found the one on the left to be on the bottom, and the one on the right to be on the top. Whichever way you find yours, press with one finger and pull them off - obviously don't pull on the wire, pull on the plastic housing once clip is loose.
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Next feed the connectors through the intake runners, and remove it completely...do this for both sides.
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Next disconnect the vacuum line from the back of the plenum. There is no clamp here, just pull the line right off.

***NOTE FROM ERNIE: This is the vacuum line that runs to the vacuum tank, which hold the negative pressure for the air injection valves, and for the intake compensation valve. It's located to the bottom left of the air box.

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Next disconnect both vacuum tubes from the from of the plenum, which run to the fuel pressure regulators.
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Next loosen the clamps holding the vacuum lines for both purge valves. One on each side of the front of the plenum, and remove them.

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Next up are the 20 bolts holding the intake plenum to the heads. You may want to take a break before doing this part, especially if you have a bad back. Some of these are in a S.O.B. location. You will need a long attachment with a universal joint for some and wobble for some. Most are a straight shot, but a few are in a tough spot.
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