Exhaust Manifold Flange - Cracked

[KS Dave]

While reviewing pictures for a blog entry on my engine hose replacement, I noticed this on my exhaust manifold flange. I'm going to try and get some better pictures later this week.



I'm guessing it's only partially cracked along the edge. Keeping in mind, I run my engine to get in and out of the harbor on our lake; probably 15 minutes each direction after warm-up. How concerned should I be with this? A new one is around $350 (yikes!). Does this affect the manifold at all? Damage possible? A new one of those is $1200, and that's probably a new engine event. I would rather err on the side of caution, but if I can take it off, patch it with JB Weld and a new gasket, I'd much rather. Or, if it's not a big deal to leave it as-is, even better.

As a side note, I see a lot of the white heat shield wrap on other engines posted here. From what I've read, it helps the exhaust gas exit the system faster. Is that the primary reason? Or are there others? Should I consider installing it? If so, how far do I wrap it? My water is injected in the elbow you see to the left (just off-frame).




If it's a "more info needed" situation, I can sit on this thread until I get more pictures.

 

[Dave G.]

In looking at the first picture the flange face looks like it may be warped or is it just the angle of the pic ? You may be able to get that welded, I have had exhaust manifolds for cars successfully repaired that way. You would still have to remove it and take it somewhere. I don't see any visual signs of leakage so maybe just keep a close eye on it and carry on. If you start hearing a ticking sound or seeing any black or gray discoloring you'll know it's time.

 

[Kevin A Wright]

Your main concern should be CO poisoning in the cabin. I don't see any soot buildup so it may not be leaking exhaust yet, but you might check the batteries on your CO detector.

I agree it might be able to be repaired. Those are usually cast iron which doesn't weld well, but if you find an old coot who knows how to braze, it could be successfully brazed and work just fine. The other question though is why it cracked in the first place? Is there some load being put on it when the engine is running somehow? Just doesn't seem like a likely spot to crack.

Kevin Wright
E35 Hydro Therapy

 

[Pete the Cat]

I am not familiar with your specific engine, but I think you have a problem that requires immediate attention. If that flange is similar to the ones on the Universal 25 series, you could leak coolant back into the engine cylinders with a gap like that and that would likely cause a major overhaul at best. It does not look like a surface crack from the picture. Looks like the flange is warped (engine has been through an over heat situation?) and needs a machinists attention for repair or replacement. Soon. Make sure you use the proper gasket material and sealant. This is a very important for your health and for the health of your engine. Empty all the coolant out of the engine before disassembling this--your engine manual will tell you where this is.
The exhaust wrapping is to keep the heat out of your engine compartment (damaging or limiting the output of your alternator). Easy to do yourself.

 

[KS Dave]

Your main concern should be CO poisoning in the cabin. I don't see any soot buildup so it may not be leaking exhaust yet, but you might check the batteries on your CO detector.

Boat didn't have a CO detector - I have a brand new CO/Smoke in a package ready for install. Haven't really run the engine much.

I agree it might be able to be repaired. Those are usually cast iron which doesn't weld well, but if you find an old coot who knows how to braze, it could be successfully brazed and work just fine.

Maybe replacement is in order, then.

The other question though is why it cracked in the first place? Is there some load being put on it when the engine is running somehow? Just doesn't seem like a likely spot to crack.

Ray's thoughts on overheating might be relevant.

 

[Kenneth K]

My first impulse, based on my M25 experience was to say replace immediately. On the M25, that flange holds all the coolant in the manifold. Or, as Ray said, could backflow into the valves if the gasket is breached.
(exhaust comes out the square port, the rest is all coolant)

But your engine diagram shows only one opening, for the exhaust, so the tank appears to be "sealed" and perhaps no coolant would be released if the flange is damaged or removed.

That flange is a high-stress area because of the weight of the piping, injection elbow, and hoses, all hanging off the back of a hot, vibrating engine. Since the metal itself is cracked, I doubt any repair will ever be as strong the original part was. I would guess that the crack will only get worse with use, repaired or not. I'd guess you'll eventually be getting exhaust fume leaks, too. As for damage to the manifold, I wouldn't expect any at all at this point. However, if the flange were to crack off and gouge or scratch the back of the manifold, you might have a harder time getting a good seal when you re-gasket.

I'd say the clock is ticking and the crack will only get worse. I don't think welding or patching can work in the long run. I'd spring for the new flange and gasket, sooner rather than later.

 

[KS Dave]

Thanks for your thoughts, Ray. Here are some comments/questions - appreciate further thoughts from you or anyone else with experience on diesel engines.

I am not familiar with your specific engine, but I think you have a problem that requires immediate attention. If that flange is similar to the ones on the Universal 25 series, you could leak coolant back into the engine cylinders with a gap like that and that would likely cause a major overhaul at best.

From what I know, Westerbeke and Universal are the same company with these being a bit older than the Universals. Functionally, I think they are very similar.

I believe you on the risks, but I'm having a hard time visualizing what the manifold looks like on the inside. I realize I fill the coolant on the top of the manifold, so it's part of the fresh water cooling system. How would I know apart from pulling the head if coolant has gone into the cylinders?

It does not look like a surface crack from the picture. Looks like the flange is warped (engine has been through an over heat situation?) and needs a machinists attention for repair or replacement. Soon.

Ugh. That's not the news I was hoping for and hopefully I'm not opening a can of worms once I take this flange off to find more damage. However, it's entirely possible the engine has been in an overheat situation before I owned it as the raw water impeller was completely destroyed when I went to replace the impeller. I don't know many times and for what duration it might have been run like this.

Make sure you use the proper gasket material and sealant. ... Empty all the coolant out of the engine before disassembling this--your engine manual will tell you where this is.

Is there a sealant I need to use in addition to the gasket? I've never done work like this before.

Dang - I just re-filled the coolant after re-installing the heat exchanger. I'm not sure the correct way to drain the coolant - the manual I have (from here) doesn't seem to cover that. It all just dumped into the bilge when I removed the heat exchanger (I didn't think about officially draining it). Generally, where does the coolant drain from?

The exhaust wrapping is to keep the heat out of your engine compartment (damaging or limiting the output of your alternator). Easy to do yourself.

I only need to wrap to the point where the water is injected, right? Or all the way down to the lift?

 

[KS Dave]

Thanks, Ken. I took too long to reply to Ray and you answered some of my questions here.

My first impulse, based on my M25 experience was to say replace immediately. On the M25, that flange holds all the coolant in the manifold: (exhaust comes out the square port, the rest is all coolant)
But your engine diagram shows only one hole, for the exhaust, so the tank it appears to be "sealed" and perhaps no coolant would be lost if the flange is damaged or removed.

As I described in my reply to Ray, I don't know what I don't know about the manifold. I'll be taking some pictures for posterity as I take it apart but I think there's only one other WB10-Two E26 on here and I know he uses a mechanic.

You give me hope that maybe there isn't damage beyond this.

That flange is a high-stress area because of the weight of the piping, injection elbow, and hoses, all hanging off the back of a vibrating engine. Since the metal itself is cracked, I doubt any repair will ever be as strong the original part was. I would guess that the crack will only get worse with use, repaired or not. I'd guess you'll eventually be getting exhaust fume leaks, too. As for damage to the manifold, I wouldn't expect any at all at this point. However, if the flange were to crack off and gouge or scratch the back of the manifold, you might have a harder time getting a good seal when you re-gasket.

Great thoughts. Do you agree with overheating being a potential culprit in helping this along? If the freshwater system isn't being adequately cooled by the raw water system, that means much hotter exhaust is going through this manifold and ultimately through the whole system, right? The extra heat can stress these parts (among others). Is my thinking correct, here? Or could this be simple wear and tear?

I'd say the clock is ticking and the crack will only get worse. I don't think welding or patching can work in the long run. I'd spring for the new flange and gasket.

I found OEM parts on eBay, actually. I have a new flange, gasket, and the nipple (in case the old one is stuck). Got it for $310 shipped. I'd rather have that $300 for something else, but I also like my engine.

 

[Kenneth K]

Great thoughts. Do you agree with overheating being a potential culprit in helping this along? If the freshwater system isn't being adequately cooled by the raw water system, that means much hotter exhaust is going through this manifold and ultimately through the whole system, right? The extra heat can stress these parts (among others). Is my thinking correct, here? Or could this be simple wear and tear?

Wouldn't have been my first thought. Look at that overhead picture of your engine. The manifold still has much more "air space" around it than the rest of the engine. I would think overheating would show up more in valves & internal block parts, but I'm no engine mechanic. I'd guess just wear and tear, but even this, as you say could be worsened by overheating.

I found OEM parts on eBay, actually. I have a new flange, gasket, and the nipple (in case the old one is stuck). Got it for $310 shipped. I'd rather have that $300 for something else, but I also like my engine.

Yeah, definitely the way to go! I use eBay more and more for this kind of stuff lately.

 

[KS Dave]

Wouldn't have been my first thought. Look at that overhead picture of your engine. The manifold still has much more "air space" around it than the rest of the engine. I would think overheating would show up more in valves & internal block parts, but I'm no engine mechanic. I'd guess just wear and tear, but even this, as you say could be worsened by overheating.

Thanks for your thoughts. Might not be the root cause, but any overheating certainly didn't do it any good.

So, if the biggest risk is the elbow falling off the back, would running it in and out of the harbor this weekend be inadvisable? We have a big event with our club this weekend and I was hoping to be able to get out. It's a 10 minute motor in and out with warm-up time. I know it's ultimately up to me, but is my risk low? I'd rather bum a ride on another boat than risk ruining my engine. But, I'd also really like to sail.

Anyone else familiar with this manifold and can confirm what Ken sees in the diagram?

(I trust you Ken, don't misunderstand)

 

[Pete the Cat]

Thanks for your thoughts, Ray. Here are some comments/questions - appreciate further thoughts from you or anyone else with experience on diesel engines.


From what I know, Westerbeke and Universal are the same company with these being a bit older than the Universals. Functionally, I think they are very similar.

Looking close at the diagram, I think the risk of getting coolant back into your engine is minimal. It seems that, unlike the 25 and 25XP, you have a separate hose and section. Generally, there is a spigot on the side of the block to effect draining all the coolant. If your heat exchanger is lower than the cylinders, you probably can get most of it out through the hoses.

I believe you on the risks, but I'm having a hard time visualizing what the manifold looks like on the inside. I realize I fill the coolant on the top of the manifold, so it's part of the fresh water cooling system. How would I know apart from pulling the head if coolant has gone into the cylinders?
I agree with Ken that you do not have much danger here of this happening in this design.

Ugh. That's not the news I was hoping for and hopefully I'm not opening a can of worms once I take this flange off to find more damage. However, it's entirely possible the engine has been in an overheat situation before I owned it as the raw water impeller was completely destroyed when I went to replace the impeller. I don't know many times and for what duration it might have been run like this.
I fear you have a problem there, but I also think you could motor for 10 minutes each way. Just keep the windows open. CO is odorless and deadly.

Is there a sealant I need to use in addition to the gasket? I've never done work like this before.

I use red RTV high temp on these gaskets--don't over do it. You can buy exhaust gasket material and fiberglass wrapping tape and stainless wire at most auto parts stores and make your own gaskets.

Dang - I just re-filled the coolant after re-installing the heat exchanger. I'm not sure the correct way to drain the coolant - the manual I have (from here) doesn't seem to cover that. It all just dumped into the bilge when I removed the heat exchanger (I didn't think about officially draining it). Generally, where does the coolant drain from?


I only need to wrap to the point where the water is injected, right? Or all the way down to the lift?

Only from the exhaust flange to the water injection.

 

[KS Dave]

Thanks to everyone for their help looking at this.

 

[KS Dave]

As an overdue follow-up, here's a better picture of the flange. You can see cracking all over it.


After breaking the studs trying to remove the nuts (DOH!), I was finally able to use a bernzomatic torch to free the broken studs without it turning into a major affair. The old flange crumbled into pieces as I removed it (it was stuck pretty good). The metal was very brittle.



Here it is after cleaning the surface and installing new studs, gasket, flange, nuts, and nipple. This isn't final state - need to add lock washers and gasket sealant.

 

[Kenneth K]

Good work getting the broken studs out. That can't have been easy.

 

[KS Dave]

Good work getting the broken studs out. That can't have been easy.

Thanks, Ken. I was sweating it, for sure! I was not looking forward to the alternatives. I have to remember that some heat, judiciously applied, can work wonders on old bolts/nuts/studs. I tried to Magilla-Gorilla it first, and that led to broken studs. Lesson learned, here.