454 Crusader has Steam

"Well, first off, I read most

"Well, first off, I read most everything I could on this forum relating to my problem. Seems common but I have yet to fix my problem. I have a 2000 351 Silverton with 454 Crusaders. I had it stored outside this year for the first time and first trip out I had overheating and steam from my starboard exhaust.

What I've done so far:
Closed seacock and unscrewed bleeder to check water intake. Good pressure coming in. No obstructions.
changed impeller. took off pump and the old impeller was in pretty bad shape. bearings and gasket seemed fine.
removed hose from U-Cooler and cleaned rubber parts out from old impeller.
removed hose from U-Cooler to thermostat to see if there was any buildup from zinc pencil. no obstructions.
Removed zinc pencil from bottom of U-Cooler. in good shape and water drained fine.
Pulled all eight plugs and did compression test on each chamber. No leaking and all registered around 160. Broke 3 plugs and replaced with new ones.
I was low on oil but topped off several days ago. No oil loss and it looks fairly clean.

After all this, I'm still getting steam from my exhaust at higher RPM's. Water flow is still impaired as I'm not getting as much from the starboard as the port side. My thermostat registers about 140 now so the overheating problem has been resolved. No steam at idle but still steaming at 3000 RPM's.

From what I've gathered from other posts here is what I need to check:

There could be something still wrong with my U-Cooler (oil cooler) but I'm not sure what.
My belt on my pump could be too loose. It doesn't appear to be maybe could be at higher RPM's.
Could be an air leak going to the raw water pump. Doesn't appear to be but how do I check?
Some posts said that I could have an air pocket somewhere in my cooling system. How can remove the air pocket.

What am i missing?"

"I take it that this is a RWC

"I take it that this is a RWC system. You might consider plumbing the water hoses to bypass the oil cooler for a 30 minute test. The zinc "plugging" occurs in a spot that would demand you unsweat the bottom of the cooler, just to inspect."

"Yes, its a RWC system. I'

"Yes, its a RWC system. I'll give that a try. If the water discharge increases, would that mean that I have something wrong with the oil cooler? Should I go ahead and flush the oil cooler? If so, how? Thanks for the response.

Also, on a side note. When I overheated the engine the first time out, I melted the resignator from the riser (sound right?). I'm not an engine guy. When I pulled the muffler and exhaust hose off, I pulled out the resignator from the water in the muffler. I took it to a service center and they told me it was a resigntor from the riser and it prevents water from moving back into the engine. I ordered a new part and will put on later this week. Could that be a reason for some of the problems?"

"Resonator...."common"

"Resonator...."common" name applied to part installed at elbow to help minimize water intrusion via exhaust. Melting it was due to the lack of adequate flow of cooling water, not the reason for it. If the issue is restriction in the oil cooler, expect the other elbow to loose it too.

If you bypass the cooler and the flow increases (& steam goes away), the oil cooler needs to be fixed. Fastest way is to put on new oil cooler. Other approaches include the muriatic acid bath and disassemble and clean the oil cooler, both described in previous postings on this board.

You CAN'T effectively remove the zinc particle plugging by removing a hose.

The other thing you need to be concerned about is the other engine. It has probably been exposed to the same maintenance cycle as the problem one. Definitely the same environment...Point is this When something happens to one, the other isn't too far behind."

"Thanks makomark. I went out t

"Thanks makomark. I went out to the boat today and did exactly that. I bought a 5 ft. poly clear tube and connected it from the water pump directly to the thermostat fitting bypassing the oil cooler. I was able to see the water move through the tube. Again, it was fine at idle but when I pushed the RPM's up to 3000, it started to steam again. At higher speeds I did see some small bubbles pass through the tube. Not sure if this is normal but it did show me that the water pump and the new impeller are moving water through to the thermostat at a good rate.

I killed the motor and hooked up the hose from the water pump to the oil cooler. Then I hooked up the poly tube from the other end of the oil cooler and turned on the motor until it turned over. I shot the RPM's up to about 2000 for about 2 seconds then killed the motor. I wanted to see if the water pushed anything out of the oil cooler. Nothing but water and seemed like good pressure.

I'm not sure what's next. Possibly the riser or elbow? I did let the engine run for 30 min while bypassing the oil cooler.

Thanks for the help this far. Much appreciated. Looking forward to new suggestions as I'm actually learning a ton."

"There is a pressure relief va

"There is a pressure relief valve in the housing near the thermostat. That might deserve an inspection.
Also, I see you are in MI now. Have these engines only seen fresh water?"

"Thanks DD. Yes, these engines

"Thanks DD. Yes, these engines have only been in fresh water. Last winter was the first year I stored it outside. I'll check the pressure valve on the thermostat and see what I find. Should I leave it open and start the engine up for a minute to release any air?"

"You will have to split open t

"You will have to split open the thermostat housing assembly to find the pressure valve. I'm not an expert on the RWC systems, but it seems reasonable to expect that valve to open at the higher rpm's, in order to move more water thru the exhaust system. So, even though you may have OK engine temps, you still may be having reduced flow thru the manifolds and into the exhaust. The other item of interest is back to the raw water pump. Was there cover scoring or cam wear inside the pump?"

"Matt,

I can feel your angs

"Matt,

I can feel your angst with this problem. I have never truly identified how it was solved on our boat since so many elements had been changed at the same time as part of the overhaul but I am anxiously awaiting your result...Good Luck.

PS... With all the new stuff on the vessel, I still get some steam at higher rpms but temps are only around 140 so far so ....?"

"I'd be inclined to pull t

"I'd be inclined to pull the elbows. You may be able to salvage what you have by knocking out all the loose crud that has most likely accumulated at the port where the water enters the exhaust stream. After rereading the entire thread, that area is prime for consideration as you cooked the resonator off. I'd also add a line to your budget to start funding four new elbows as you will likely need them by next year."

"Thanks for the great feedback

"Thanks for the great feedback. I will be going out to the boat this afternoon to see check out the elbows. Do you know of a good site that I can get a diagram of my 454 crusaders that would label the parts for the cooling system, etc... I will let you know tonight what happened with the elbows."

"the newer stuff is on line he

"the newer stuff is on line here:

http://crusaderengines.com/Owners%20Info/manuals.html

the 7.4l parts book looked ~ 10 MB so it may take a little while to download"

"i've been a Marine Mechan

"i've been a Marine Mechanic for a long time, and I've seen what appears to be steam coming out of the exhaust on large (and small) cruisers for some time. Yet engine temps are in the normal range. My conclusion, it's not steam, outhet water is just not hot enough. I've traced it back to old fuel. Could be additices buring off or just old fuel. This is very true of 454's and 5.7L/ 350 cid engines."

"Hey all, thanks for the great

"Hey all, thanks for the great feedback.

I was able to fix the problem and it turned out to be that I had a large quantity of rubber from the impeller clogging up both hoses to and from the raw water pump. I did end up taking off the elbow and taking apart the thermostat housing and all seemed to be fine there. I replaced gaskets on the elbow, thermostat and water pump, removed all the rubber and it runs fine.

After taking off the hose at the raw water pump from the seacock, I stuck a coat hanger down the hose and it freed up the all the rubber from the impeller. I was thinking that it would work its way through the old impeller and get caught up in the screen on the oil cooler. Not the case. It never made it back through to the other side. Once I loosened it, I pointed the hose at my bilge compartment and opened the seacock for a couple seconds to make sure I got it all out. Worked like a charm.

Once I finished I replaced the impeller on the other RWC pump. It was ready to go also. I went through the same process changing out gaskets and cleaning out the oil cooler as well. Both engines are purring like a kitten. More importantly, I got to know my RWC system much better and did some long overdue maintenance.

I'm still getting more steam out of the port side where I had the original problem but it appears to be normal as many people commented that steam is normal. Its not like it was that's for sure.

By the way DD, there was no scoring or cam wear inside the pumps. They looked flush and clean.

Thanks everyone."