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Exhaust manifold failure

jeff58

New member
" I have two new 2002 Crusader

" I have two new 2002 Crusader 5.7L MPI engines in my 89 Luhrs 320. I have had all 4 exhaust manifolds fail withing 30 hrs. of operation. Two of the replaced manifolds have now failed. This is all being done under warranty, but I've about had it. Nobody seems to have an answer except for "faulty cast iron manifolds" But, 6 of them?!! The engines are closed loop cooled and the boat is in fresh water. Does anyone have any idea what could be happening here? "
 
"How are they failing? At the

"How are they failing? At the mating surfaces? I'm thinking gaskets here. How's the pressure in the cooling systems? Just finding water in the oil, or vice versa, isn't specific enough. Will they pass a pressure test before or even after failure?

"
 
" They are failing through the

" They are failing through the wall between the coolant and the exhaust. There is no water in the oil. The coolant passes directly into the exhaust manifold and falls onto the head. When the engine is off, it leaks into the cylinders through the exhaust valves. The next time the engine starts, it starts hard and coolant burns. The failure point gets large enough, that coolant dumps directly into the raw water and discharges through the riser. I don't know if they'll pass a pressure test before the failure. They obviously won't after the failure. "
 
"Well, that sure sounds like a

"Well, that sure sounds like a casting failure. My guess is that the manufacturer may have had a bad run of castings and your dealer/shop is being supplied from the same "batch". You are certainly justified in asking for a different brand or supplier to avoid the bad castings, but it may depend on how flexible Luhrs or Crusader is in reimbursing the dealer for the warranty work.

"
 
" Thanks. That's about al

" Thanks. That's about all I've been able to come up with. When we questioned Crusader about the frequency of failed castings they swear that manifold warranty claims are not unusually high. If it's a bad batch of castings, this has to be happening all over the place. It's not possible that I'm the only one getting the bad ones. Anyway, thanks for your input. I appreciate it. "
 
I would be extremely wary of

I would be extremely wary of hydrolocking the engines. This is when the water and coolant gets into the cylinders. It can cause a lot of internal engine damage when the piston tries to rotate in a combustion stroke. I would get some guidance from the dealer about future damage from this problem.......
 
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