cracked manifold????

[cmtaylor777]

If anyone has any advise I would greatly appreciate it.

I recently too my 2004 launch in for winterization. When the service was done the shop asked me to come in and observe what they found. The mechanic is stating that there are small hairline cracks in both right and left manifolds. He pointed out that there was a rust color on the bottom of both manifolds. He "officially" advised me to replace both manifolds. He then "unofficially" gave me another suggestion. He stated that they could grind down the paint and JB Weld the small cracks then repaint. He said you wouldn't be able to tell it was even worked on.

This then made me a little leery. Not sure if this is common or if this is the act of a mechanic needing to generate a little business. I told him to hold off on doing the repairs. I figured if its as basic as a little JB Weld, i could handle doing the repair myself.

Long story short......what do you guys think? Is he full of crap or could this be legit?

Thanks in advance for any suggestions.

[86Pirata454]

can you pressure test the system? See if it leaks then go from there.

[Fman]

If anyone has any advise I would greatly appreciate it.

I recently too my 2004 launch in for winterization. When the service was done the shop asked me to come in and observe what they found. The mechanic is stating that there are small hairline cracks in both right and left manifolds. He pointed out that there was a rust color on the bottom of both manifolds. He "officially" advised me to replace both manifolds. He then "unofficially" gave me another suggestion. He stated that they could grind down the paint and JB Weld the small cracks then repaint. He said you wouldn't be able to tell it was even worked on.

This then made me a little leery. Not sure if this is common or if this is the act of a mechanic needing to generate a little business. I told him to hold off on doing the repairs. I figured if its as basic as a little JB Weld, i could handle doing the repair myself.

Long story short......what do you guys think? Is he full of crap or could this be legit?

Thanks in advance for any suggestions.

Do you have any pictures? I would think welding it would be a better long term solution. Although JB Weld does work well on the right applications.

[Salty87]

if you've ridden in salt alot, that's about all you can expect from manifolds or risers. can't imagine there's much salt near you though.

there wouldn't be any guarantee of success with jb weld. pressure testing would be best. you run a pretty big risk of damage if your engine is ingesting water.

that said, i've got some jb weld on one of my manifolds. tiny little crack and all seems well so far.

[michael hunter]

Did he say what caused the cracks?

[cmtaylor777]

We recently got several days of off and on freezes. It has been at their shop for a month now. I didn't really complain about it taking so long since I didn't have to bother with it being stored. I question if they drained it as soon as I dropped off the boat but there is no way of proving if they did or not. He said it must have happened during one of the cold spells before I dropped it off.

With myself being a newby boat owner, I just questioned the fact that the mechanics are being straight up with me. I have no way of pressure testing it so I am really at their mercy.(without getting a second opinion) I guess if they were really trying to milk me they would have told me to replace the manifolds.

Does anyone know how hard it would be to do the repairs myself? Are the manifolds "pull off and put on" parts? Never really broke a motor down so I don't really know for sure what it consists of.

[sybrmike]

I don't know what style manifolds they put on in 2004, but repair options will depend on the material of the manifolds. If they're the traditional cast iron - you can't weld 'em, but may be able to braze. They're not structural & only see a few psi of pressure, so JB may be an option - I've seen that stuff hold up pretty well in the right circumstances. Depends on where the cracks are located & how hot it gets in that area.

If they're the slick new fabricated steel header type, welding would be the best option IMO.

[cmtaylor777]

Pretty sure they are cast iron.

[agetech]

I left water in one of my exhaust manifolds years ago in a VIP inboard. Found out it was cracked when I was in the middle of the lake and had water coming up in the bilge. The boat was only two years old at the time. I found a a welding shop that specialized in head repair on diesel equipment. They heated the manifold in a furnace and then brazed the crack. I never had any trouble with the repair in the five years I had the boat after that.

[cmtaylor777]

Well here is the concern that I have. When I showed up to look at the cracks, the Manifolds were still on the motor. he points out that the cracks are on the bottom where there was a little rust showing. I know that he didn't remove the Manifolds and test them. And I know if the cracks are small hairline cracks then how would he be able to tell that they were there. I could barely get down low enough to see the rust.

It just seems fishy to me.

[docdrs]

are the cracks on the manifold or the riser? did you have problems with water in the bilge, or was there exhaust/noise coming from the manifold? how did he discover it?

[agetech]

They could have been leaking when the mechanic winterized the engine. Did the he run the engine to fog it? If he did, the leak would have been noticeable.

[Irish_Jack]

I would hedge bets that everything is kosher. GM inboard manifolds will usually crack close to the center exhaust ports.. sometimes all the way down to the manifold bolts. I traveled to one of our other locations this past fall durring winterization to take alook at three indmar GM engines that had hairline cracks--all in the same places. It almost seems like a heat transfer problem(caused by poor water circulation) or impure casting problem... I will talk to one of the other senior techs that is at that location and find out what the solution was. He is the one who did the follow-up. I was sent there because I was the only other senior tech in the district when he was on vaca. Keep in mind indmar's are extremely sensitive to week impellers...

[szarik5]

I had a freeze-up problem on my TS6M pcm cast iron manifold. Water froze inside of it and created a hairline crack along the side of the manifold. If not the rust and visible water dripping it would be difficult to see.

Last thing I would do is try to depend on JB weld to plug it. Do it right! The manifold may be perfectly fixable but take it to a reputible shop too have it cleaned (inside and out) and checked. You want it to be cleaned good so you dont have any oil or anti-freeze soaked into the cast. The cast can act like a sponge and hold chemicals.

Braze it - Take a large propane torch (the kind on a wand -$25 at menards) and get the entire manifold hot. Keep heating it while you are brazing it (about the easiest thing to braze). When done, run it into your house into a pre-heted oven to full heat and reduce the heat by 50F every 10 minutes and leave it in there untill cold.

The heating could warp the manifold a bit and it should be checked and possibly planed flat. Not a bad idea to get it planed anyways to clean the surfaces under the gaskets.

My suggestion is to fix it right or buy new manifolds.

[docdrs]

Do a search on You tube, there are vids on how to do, sounds like they are close to the port exits and tend to agree with Jack and szarik5. Plus a new manifold doesn't look that expensive

[cmtaylor777]

DOCDRS,

Can't really answer the question referring to having water in the bildge. I was also having issues with my front ballast overfilling when I was in motion. Turned out to be the silonoid.

They did do a full winterization and fog the engine. I guess they could have discovered the problem then.

Guess I'm in denial. Just got the boat in december and was looking forward to getting a little use before having to shell out money for repairs.

Thanks to everyone for giving advise. I never post on forums but I have found this to be extremely helpful.

[beast 496]

Wait until spring, If the crack is small and on the outside only it will basically rust shut. Exaust water pressure is only around 3 to 5 lbs in this area. If you do notice some seepage, save yourself some money and use some Marine Tex to seal the crack. No reason to go into extra expense of removing and having the unit welded. Cast Iron is not easy to weld anyway. I have fixed dozens of maniolds and blocks this way, No it is not new but $20 verses $200 it is up to you Al

[cmtaylor777]

Thats what I'm talking about! Is it easy to apply. Forgive me, I haven't ever heard of the stuff.

[beast 496]

Yes, Marine Tex is used in the Marine service industry quiet abit. Basically industrial JB weld. Look at Jamestown distributing for supply. The Black or grey version is the strongest. Easy to apply clean up with acetone. overnight to set up. Al

[cmtaylor777]

Thanks Beast

I will give that a shot.

[beast 496]

Just remember to drain the manifold before applying the Marine tex. route out the crack, grind the paint with a 2" grinder for good adhesion. Wipe all mounting area with acetone and let flash dry. Easy to repair. Al

[OUI]

If the cracks are on the outside you can deal with that. On the inside, you won't be able to get in there. There is a product called Alumaweld and it works on cast. I've seen it work and it works great. No welding knowledge is needed, so you can do it yourself. JB has never worked for me, and MarineTex has been marginal in these types of applications.

Good Luck, here's the link to Alumaweld.

http://aluminumrepair.com/land/index.asp?src=google&gclid=COH74MXBtp8CFRIMDQodajWc4A

[cmtaylor777]

thanks oui

i will check it out.

[cmtaylor777]

How hard is it to remove the Manifolds? Not really an experienced motor man so what am I jumping into. I can put things on and take things off but how extensive are we talking about here. Shop wants 3 hours labor to repair. 300 bucks. Worth the trouble?:confused::confused::confused:

[docdrs]

Not sure how hard as have never removed marine mani's, but i'd spray penetrating oil on the bolts before to minimize snaping the bolt heads off. then did you check out what a new mani is worth? if your doing the labour

[cmtaylor777]

didnt price out yet. wanted to weigh the options first. Not sure I am experienced enough to attack this problem yet.