I responded a few times elsewhere, but those are burried in other threads, so I combined some of that here for easy finding. I have a 2001 MGM since 2001, I bought it because I needed a 4 door car, I liked the looks, and as a state police officer (Trooper) I saw how durable my '98 and '00 CVPIs were. Later I got a '06 CVPI after driving the '00 a really long time. Bulletproof is a word.

My Mercury still has it's OEM all plastic PI intake, no leaks, 93,xxx miles. Back about '05 or '06 I bought a used intake off a near new CVPI that was wrecked, it has the aluminum X-over, I thought I might need it one day. I think it's a '03 maybe.

Last summer I was going to put it on the '01 MGM, but first I made some changes. I took the aluminum X-over off, removed the seal rings (was going to put new ones in, but changed my mind as the thin plastic walls showed signs of impending failure) … so I cleaned out the channels and surfaces, applied a good dose of J B Weld on the surfaces & filled the channels, then I reattached the aluminum X-over to the intake, tightening all 6 of the small bolts underneath and used masking tape on bolts put through the "intake bolt holes" with nuts in place of the cylinder heads to let the J B Weld cure hard. Slow, original cure J B Weld cures over 24 hours, but is still formable after a few hours for smoothing with a wet finger, etc. It's good to near 600 degrees after cured. I know it sticks to aluminum and the plastic well from prior uses.

I also took a old but new sharp 5/8" drill bit and slowly by hand reamed out the plastic nipple at the rear until I had a snug, not tight, sliding fit with a piece of 1/2" ID, 5/8" OD copper pipe inserted, I roughened the copper with sand paper, tapered the end slightly, applied J B Weld to it and with a twisting motion, inserted the copper until about 5-1/4" were down in that nipple and into the meat of the intake below.

It's likely fully cured.

I think the intake is near about bulletproof now. I have not yet installed it on the car, but I have the new better Fel-pro gaskets with aluminum frame and I'll make an alternator bracket if need be (but I think I can modify mine OK). I have the correct thermostat housing and bolts too. No pics as PS got greedy. I have new injector seals too. Even have silicone hoses ready, but not sure I'll use them, they were cheap on RA clearance.

I just need to do it. Last summer I put it off, then again this summer as C-19, etc … other chores too, but maybe now I'll get on it here soon.
Why I did what I did to my updated one, I think it'll outlast the car to be discovered in digs in the year 2525 even, unless fire or something like that. What I found when I was doing it was the "o-ring like" seal fit in a channel with a narrow wall on the coolant side, unsupported. The seal is squeezed in use and pushes the wall outwards into the coolant. The J B Weld more than addresses that issue as it seals and hardens to form in the channel and across mating surfaces … as does the copper tube in the rear nipple solve the fragile plastic tube problem area. I really don't see another failure point.

I use original J B Weld, it likes to have 24 hours to cure, it's good to near 600 degrees, and is "workable for a fair period prior to cure, and I know it has to be sanded or ground or chizzled off aluminum once cured (used it to mend a busted aluminum casting on the high pressure lines of a AC compressor just a few inches from the #1 header tube of a '92 T-bird Sport 302, never leaked again) and seems to be near as well adheared to the plastic in my trial on the '01 intake on the car now where I applied some to the plastic water crossover, it still is stuck fast in spite of many heat/cool cycles. I am of the opinion that the aluminum and plastic are very near the same expansion rates at the temperatures involved.

I even think some of the busted plastic crossover failures could be patched with it if some reinforcement were used, but unless emergency, I won't try that just yet.

Where the all plastic intake (on my '01 Merc now) seems to fail is in the broader unsupported areas like behind the alternator and places around the thermostat well, places that see coolant pressure. A support (girdle) of wood or metal applied with J B Weld as a filler would look awful, but would work I think. The rear nipple is brass inserted into the plastic on mine, I know the tower can crack and "let go" of the insert so I added a hose clamp to the one on the car around the plastic to keep it from cracking and letting go. Then, there is that insert for the temp sensor in the crossover top side, I added J B Weld there and a clamp too.

The wire wrapping at top and a clamp below were used to prevent cracking while I enlarged the nipple inside, by hand, NO DRILL MOTOR. I smoothed the J B Weld after it started to stiffen with a wet finger, I used tape on the bolts to aid removal for installing and to keep intake holes bigger in the J B Weld. I will remove the wire wrapping and I reinstalled the clamp which I'll leave in place once in use … or maybe I'll fit a copper ring in it's place with some more J B Weld? I did paint the aluminum black.

Well maybe it'll hold up better then stock ones!!

Well, I must say that it has held up really well in these last "13 plus" months since I done all that to it …
… and with temps cooling off (was a hot & humid summer here), I again hope to swap it onto the Mercury soon …
… after all the rains slow down. In case anyone wonders about channels, here is aluminum crossover removed prior to sealing it all with the J B Weld, I filled these channels too. I was going to space the aluminum and plastic apart a little to allow a good area of J B Weld to spread, but then I found there was ample recess anyway.

Today, seeing how well the JB Weld grips & hardens, I cut a 3/16" wide piece of 1/8" wall steel pipe that fit loosely over the boss or housing for that rear nipple (the one I previously put a 1/2" ID x 5/8" OD copper tube in) and put it in place of the screw clamp, with JB Weld all over it and between it and the boss, above & below too. Call it permanent as with the copper tube in it, it's gonna be OK. I also removed the wire wrap seen above on the plastic hose bib, it's just not needed.

Lastly, I need to correct this paragraph from the first post in this thread: … it should read:

Well, I'm done working on the intake. I had painted the aluminum, but I wire brushed it and I painted the JB Weld at the rear nipple, if it leaks after all this I'll just buy a new FR intake. The one on the car does not leak, but it's like a time bomb I think as it's all plastic. I lightly scuffed the paint to blend better too. Get these hurricanes beyond us first. I used bright zip ties to grab my attention.

Looks good

Great work; I knew there was a good reason to hang onto my old, leaking PI intake.
I'll be doing this mod to it soon.

Hell, I might do this to my current intake...

I know that there are products touted for just plastics, but I've looked at a lot of youtube vids and I've used the original JB Weld for a lot of things over the last 30-40 years, and that's why I went with it over the others. I know it is rock hard when cured, it takes heat well, I've never had it pop loose from a use.

I was lucky with the above intake, it had not yet started to leak or crack around those seals under the aluminum, but I think that if I had one that had, I'd open it up, remove the seals, clean the channels, plastic, & aluminum spotless, fill the channels and either press the weakened thinner failed wall back in place or smooth the oozing JB Weld into the voids if pieces were missing. In the case of the one on your car, likely it hasn't failed yet. The one that you took off, is the one that might be missing some of the walls, but after the JB Weld is set up some, wet a finger and you can smooth it to rebuild the wall around the water way.

Now, when I swap this over onto my '01 Mercury, I'm gonna remove a still UN-failed all plastic OEM PI intake (I hope). We know now the failure points.

I'm gonna visit the rear nipple on it, make sure it's reinforced, maybe add a steel ring in JB Weld too, or tightly clamp it then add JB Weld, it has a brass hose bib that was put into the boss when manufactured, I have seen they fail when the plastic boss cracks and "let's go" of the brass.

Then to the plastic crossover, the long unsupported area behind the alternator where it sometimes splits, using some 3/16" thick & stiff aluminum sheet I have to fashion a girdle that hugs both sides and is bent to form a top over it, one that will slip down over the area, and extend a 1/4"or 5/16" below the plastic on both sides and use a few long screws & nuts across them, out of sight. Install it with … you guessed it … JB Weld as a filler between the new girdle and the plastic crossover.

I have an idea to make a curved girdle to hug the T-state housing as well, but likely use clamp there, then keep that as my "backup spare".

What I haven't figured on yet much is the brass insert where the temp sensor screws in. Last year I noted some green there which told me it seaped, so I wire brushed it clean with brake clean and used a narrow clamp as a "wall" and filled in with JB Weld. No more seapage. I installed a clamp at that rear nipple below the heater hose then too.

I had mentioned repairing a section of the AC compressor on a '92 Thunderbird 302 Sport, it was a few inches from the exhaust tubular manifold #1 cylinder, sometime in the past a mechanic had repaired it after it chipped with JB Weld, but he had applied the JBW over the joint and the O-ring was exposed due to the chip … and in time, the JBW had shrunk the rubber and it leaked Freon. This is where the AC manifold for hoses attached to the AC compressor back. I chipped it away, ground some too, it was solid, reformed the channel for the O-ring using a narrow piece of shim stock to create a wall … and put it together … no leaks, then I covered the area with JB Weld again but now it could not get to the rubber because of the shim stock.

On an air cooled Triumph Trident motorcycle, the center cylinder had a thread insert in the aluminum head and it came out with a plug once. Actually, all three had inserts but the middle one was put in off kilter slightly and the spark plug wasn't square with the head surface, so I added some JB Weld to the inserts thread that went to the head, greased an old plug, reinserted the insert and let it set, then after full cure I removed the greased plug and cleaned the threads and put a new plug in … 20 years later still perfectly fine.

I have used JB Weld to bed rifle actions into stocks too. I've drilled it, and tapped it too. It is just great stuff to have on hand.

Damn, and I thought that I'd done some crazy stuff with JB Weld...

https://www.crownvic.net/ubbthreads/ubbthreads.php?ubb=showflat&Number=4020574#Post4020574

I remember that!

I forget if you de-rusted the block's surface, I expect you did and likely that 4.6 is doing just fine still. They'll be digging in 2525 and find my intake and your plate with the truck rusted away.

In these Covid 19 times, I have spare time to dwell on silly stuff. I came here to edit my last post rather than add another, but it's a "no go" so I'll just quote a part of a prior post I made.
Yeah, that part.

Went out today, just moving about some, took a look under the hood of the Mercury that still has all plastic. I see where I put that clamp around the heater hose bib at the right rear of the intake where they can crack the plastic tower boss and let the go of the brass hose bib.

I took a 10mm and removed the alternator steady bracket which I had drilled out years ago and inserted short pieces of fuel injection type 1/4 hose to put the bolts through, like "bushings" … I did not tighten the bolts, just run them down finger tight on the rubber hose to dampen vibrations. The hose provides enough friction the 4 bolts stay set.

I see where I can easily wrap the plastic coolant crossover on both sides of the plastic boss holding the brass threaded insert where the coolant temperature sender lives, and I have a nice steel washer over the sender on a bed of JB Weld. This washer had a center that was "raised so I placed that surface "up". I have cut two sides of the washer, rounded the edges, and I bent the round ends up a little to keep any wire I use from slipping off. It's curing now, the center hole is a hair bigger than a 6 point 3/4" deep well thin wall socket I used to "center it" as it cures. I can drill the "webbing" between the crossover and intake runner behind it to allow me to wrap a few rounds of wire there around the crossover to act as a girdle for the sensor insert, it might leak some day but it will not blow out. I can add a piece of aluminum or thick hard rubber on the bottom of the crossover to prevent damage to the plastic as I tighten the wire wraps.



I even see a way to wrap the T-stat housing to support it. I don't think it's a high failure rate point though.

This is the issue here … I see where the plastic coolant X-over is molded in with the #1 intake runner part of the way which provides support to the rear wall, but there is no support to the front wall. This shared wall also means I cannot make the girdle for the long flat front wall like I thought as I can't "wrap" it? I can wrap the end towards the right of the intake near the sensor, but that other end towards the T-stat is gonna be a biotch I think. I'll likely just just hang the OEM all plastic intake up on a hook between floor joists with the bungs secured and call it done for a spare "just in case" deal.

IF the front wall failures are due to the alternator bracket, vibrations, etc, then I got it covered. If the coolant crossover ever did fail on the rear wall shared with the runner, likelier it was pulled away by vibrations from the alternator? My bushings should cure any such tendencies (I did run the car a while with no bracket, like a couple oil change cycles, before I did the bushing deal, it is just a steady)

If the failures are just due to age and temps and coolant psi and a thin unsupported wall, well, it's lasted 20 years anyway. I think the previously mentioned inserts are more likely fail points. I'll revisit that wall after I swap it off and get a closer look underneath in the area.

I suppose it is likely that all this is pointless as if my replacement is as bulletproof as I believe it to be … the all plastic OEM will likely never see a car again anyways?

Well, no edit. Just watching TV and thinking as I read posts "here and there". Nothing really new, just random thoughts.

Today I apply the wire or other wrap. I've decided that not really much point in trying to support that front wall or even the T-stat housing now. Will not be too much driving and I think I've addressed the most likely failure points on the OEM intake that's on the car so it'll likely be OK until I swap over.

I guess I just imagined it blowing up the day before I planned on the swap, but not very likely, and these steps likely reduced that chance. Raining a lot off & on today so definitely "not today". I've had the car out a few times, but it's still at 93,xxx miles, so "not a lot" of use this year.