Cracked Intake Manifold: JB-Weld?

[Turin39789]

99 Grand Marquis.

Heat/defrost wasn't working great Thursday morning. Figured I might have a thermostat problem.

Friday driving home and the temperature light comes on, heat gauge is pegged at 11, CEL, goes into limp mode. Hurray!

Replaced the thermostat today but got it all back together and coolant is shooting out and I see the small crack at the top of the intake manifold where the thermo sits. Now my $20 20 minute job wants to turn into a $250 all day job.

I don't wanna. Any chance at all letting some JB-Weld set in the crack to cure for a day or so will save me?

[rommelrommel]

It might, can't see what you have to lose.

[Raizinman]

Having worked on a used car lot in my youth, you would be suprised how much of a car can be held together with hangers, duct tape, super glue and JB weld. That was pretty much my complete tool box. On small cracks like what you describe, the water pressure of around 15 PSI might push the JB Weld out. Instead, you might try drilling a very small hole and then put a small screw in with JB Weld so that it won't come out. This way the water pressure won't push it out. Not the official correct way, but on old POS cars, spending $5 of $6 bucks sure beats pulling the manifold and doing it right.

[PottedMeat]

if it's like this:



maybe take out the thermostat, dry out the area around the thermostat, sand it a little inside, apply jb weld?

[bruceb]

Probably another version of a plastic manifold. They are terrible and the best way is to replace it, with a metal one (if someone in the aftermarket makes one for your motor). Car makers did this crap to save cost and a little bit of weight, at the expense of the part failing at some point.

Note: There was a class action suit against Ford for this issue, which they lost. Sorry to say, deadline to file was sometime in 2006 .. and so far, I only see plastic manifolds for that car, but Dorman seems to have one that is better than the OEM unit (you must use Dorman gaskets with it) and it costs about $200

[iamwiz82]

Some friends and I used JB weld to patch a hole in a transmission pan just to get our friend home, but it was replaced ASAP afterwards. I cannot imagine it will hold that long.

[Bartman39]

After you possibly fix (temp) that area it will crack right behind the alternator and you will be up the creek without a paddle so just replace it with a new all metal unit (manifold) and be done...

The world of plastic is not the greatest and for sure when it comes too cooling systems...

[7window]

it won't hold that long. Especially intake manifold

[Vic Vega]

Well known issue on this year/motor. The problem is the alternator support bracket is there. When the engine is run hard or near WOT, the serp belt puts a lot of physical pressure on the alternator and pulley - well, those parts are metal - the alternator bracket is metal, the intake where it bolts to is composite resin. Guess what breaks?

Ford makes a newer manifold which has a metal section where the alternator bolts on which solves this issue. Runs around $250.00 IIRC.

[Vic Vega]

Old vs. new manifold:



FYI, you have an NPI 4.6 so make sure you get the right manifold for engine/year.

[Vic Vega]

This is the correct part for your year. $187.95.

http://www.ebay.com/itm/New-4-6L-Int...a8e9c4&vxp=mtr

You can change this yourself in a few hours. Just label as you disassemble.

[DaTT]

I used JB Weld on an exhaust manifold for a boat this past summer....extreme heat and water running through it. Worked great.

[Turin39789]

I'd read some about the lawsuits, and it is indeed the bad plastic manifold. Still tempted to to try to patch it with the JB, brother suggested just RTV, and hope to get some more time out of it.

Car was inherited, hail damaged and is slated to be passed down to my niece for her first car. Spent the day doing our 2 year olds birthday and between her and the new kid not much time to play around with cars anymore. Tempted to bite the bullet and get my next vehicle now, but would be nice if a limp fix would give me some flexibility on when to fix this. Just about killed myself painting and doing trim work around the house in prep for the party.

[Rifter]

Jb weld is all about the prep and application.

Get it completly dry and oil/collant free and then apply it will probably last for years.

Apply with it covered in oil/collant probably last a couple days if that.

[rommelrommel]

I can't see RTV holding due to pressure alone.

[Meghan54]

Since the manifold is toast already, not much you can do to it will mess it up worse.

So, in that vein, may I suggest a multi-pronged attack, given the environment the patch will have to endure---pressurized chemical laced water. My thinking on this is to attack the crack mainly from the inside.


I can think of two ways to almost assure you'd seal the crack longer than a couple of weeks.

First, optimal cleaning and preparation is imperative, as mentioned previously.

1. Fashion a piece of metal to the internal shape of the manifold's outlet, large enough to cover the crack completely. Apply JB Weld to the crack, then paste the metal patch plate over the crack with JB Weld. I'd wedge it in place while setting. Bet that'd hold. I'd think about a very thin piece of aluminum. That'd be easy to shape and there's already alu in the system, so corrosion isn't a concern.

--OR--


2. Enlarge the crack from the inside in a V-shape. I'd imagine taking a Dremel with a thin cutting blade, going straight in on the crack from the inside about 1/2-2/3 of the wall's thickness, then rocking it back and forth a couple of times to create a V-shape. Clean then slather JB Weld into the V-cut you've made. Since the smaller end of the V is pointing outward, the JB Weld won't push through as the coolant gets hotter and pressure hits.

In either case, I'd also cover the outside of the crack with a coat of JB Weld. Can't hurt.

Just a couple of ideas. Either should work, I'd think. Honestly, if you've got the Dremel and the guts, I'd try the second option first, then do the first suggestion if it doesn't work out.

[JCH13]

If you really don't want to fix it 'right' with a new manifold I would suggest the following: fix it from the inside with epoxy and a small fiberglass patch. This way the coolant pressure is trying to push your patch entirely through the crack and not just off of the surface outside of it.

I don't like JBWeld. At all. It's too prone to disproportionate and poor mixing. I use stuff like this style of Loctite that ensures the proper ratio of resin and hardener are mixed properly. It's also infinitely easier to apply.



If you're doing this outside in the cold I would also suggest getting an incandescent light or a hair dryer or some other heat source to keep the joint at at least 75F while it sets (ideally for as long as it cures) as set and cure times and joint strength are heavily dependent on temperature.

[LTC8K6]

There are JB Weld versions in that packaging as well.

http://www.jbweld.com/product/j-b-plasticweld/

http://www.jbweld.com/product/j-b-kwikweld-2/

[JCH13]

Originally Posted by LTC8K6

There are JB Weld versions in that packaging as well.

http://www.jbweld.com/product/j-b-plasticweld/

http://www.jbweld.com/product/j-b-kwikweld-2/

No mixing tip. The mixing tips that come with the Loctite cartridge I showed (and also 3M Duo-Packs, Lord cartridges, etc) are the key. That's the only brand/cartridge I've found at local hardware stores that have mixing tips. I wouldn't expect your average DIY'er to go spend $50 on a cartridge gun, $15 on a bag of tips, and $10-$20 for good 3M/Lord epoxy.

The white mixing elements mix the epoxy parts as they come out and the tip can be trimmed to lay a bead of different sizes.

[SpatiallyAware]

Ugh... it's your cooling system. The last thing you need are chunks of friggin jb weld/epoxy clogging up the passages and/or radiator.

Just replace the intake.

[LTC8K6]

I don't trust mixing tips. I have to mix it myself anyway.

[LTC8K6]

Originally Posted by SpatiallyAware

Ugh... it's your cooling system. The last thing you need are chunks of friggin jb weld/epoxy clogging up the passages and/or radiator.

Just replace the intake.

That's probably the best way to go...

[JCH13]

Originally Posted by LTC8K6

I don't trust mixing tips. I have to mix it myself anyway.

I do. I've used auto mixing tips to assemble composite suspension components and benchmarked the adhesives' performance through destructive testing. They work just fine.

[Rifter]

Originally Posted by JCH13

I do. I've used auto mixing tips to assemble composite suspension components and benchmarked the adhesives' performance through destructive testing. They work just fine.

Its really not rocket science to mix jb weld.

For sure you can screw it up there is no doubt about that but once you use it a few times its not hard at all to get the mixture right just by eyeball and feel.

I wouldnt tackle a job like this if you had never used jb weld in your life but if you are an experianced jb weld user it will not be difficult at all.

I know someone who punched a 1cm by 1cm hole in the side of there oil pan when they lost a con rod and the bolt went through the side of the pan. I jb welded it with a piece of random tin i found laying around the shop he worked at at the time. Its still holding and he still daily drives the vehicle, 7 years later, never bothered getting a new pan.

So jb weld is some strong epoxy and will hold up for a long time depending on how and what you use it for.

But as i said above in previous post its all about the prep time you take and the mixture and application.

[JCH13]

Originally Posted by Rifter

Its really not rocket science to mix jb weld.

For sure you can screw it up there is no doubt about that but once you use it a few times its not hard at all to get the mixture right just by eyeball and feel.

I wouldnt tackle a job like this if you had never used jb weld in your life but if you are an experianced jb weld user it will not be difficult at all.

I know someone who punched a 1cm by 1cm hole in the side of there oil pan when they lost a con rod and the bolt went through the side of the pan. I jb welded it with a piece of random tin i found laying around the shop he worked at at the time. Its still holding and he still daily drives the vehicle, 7 years later, never bothered getting a new pan.

So jb weld is some strong epoxy and will hold up for a long time depending on how and what you use it for.

But as i said above in previous post its all about the prep time you take and the mixture and application.

I see no reason to not get auto-mixing tips. They make it easier to apply the epoxy and take any guess work out of mixing (you don't need to be an 'experienced JB weld user). They deliver consistent and idiot-proof results.

But you're right in that good results depend heavily on joint preparation. Solvent/abrasion/solvent at a minimum.