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Crusader 454 excessive exhaust steam

BarryK3

Contributing Member
Hi all,

I have Crusader 454s from about 1990. They are fresh water cooled systems with heat exchangers. Port is a Mark 4 and starboard is Gen 5. Starboard was apparently replaced under warranty early in the boats life.

I have owned the boat since Dec. Maintenance records are not available. Supposedly risers and elbows were changed about 2 years ago, no proof though. Engines have about 1100 hours on them.

I have minimal steam from both exhausts up to about 3000 rpm. Above 3000 the port engine puts out excessive steam, the starboard stays the same.
Port engine temperature stays at about 165 at 3000 rpm. Starboard is about 170.

I measured temp of the elbows with an IR gun after a 15 minute run at 3000 rpm with engines back at idle. Starboard was 98, port was 108. Engines had been idling for about 5-10 minutes by the time I measured the temps.

I recently treated both cooling systems with Rydlyme re-circulation. This does not include the risers and elbows though. Raw water pumps and impellers are new. Belts are tight.

Next step? Pull the port risers and elbows to inspect?

Thanks,
Barry
 
I used to have twin 1993 350’s and had an excessive amount of white smoke/white steam coming from the starboard engine. I also noticed my coolant was disappearing... turned out my head gasket was “rotted” and coolant was leaking into my exhaust. Check your coolant level.
 
Thank you! I replaced the coolant a while ago and the level has been stable. I back flushed the U cooler and it seemed to be OK but I will recheck it. I am going to go through the whole cooling system and see if I can find a restriction to flow. I circulated Rydlyme through the U cooler and heat exchanger for about 2 hours but it did not change the exhaust steam. The odd thing is that the engine temperature stays very low at any rpm, 160 at idle and 165 at 3000 or above. The engine without the steam problem runs a bit hotter, if you can trust the gauges.
 
I don't know about ridlyme but unless it dissolves the zinc pieces, its a futile exercise backflushing the u-cooler....
 
Thanks Makomark. I will inspect the U-coolers. Do you know what size fittings I will need to seal the oil lines so that I can remove the U cooler from the boat?

Do you think the slightly higher engine temp on the "good" engine needs any further investigation or would you just keep an eye on it? Again the port "steaming" engine temp is about 165 and the starboard "good" engine is about 170. I have not confirmed accuracy of the gauges with an IR temperature gun yet. I have not inspected the thermostats either.
 
I believe the hose ends are 1/2" inverted flare - the cooler side ends are 3/8" NPT...I think one is an odd ball but cant remember.

I believe the consensus approach is to just flush the cooler on the engine, using muriatic acid in the raw water path...all of the crud accumulates in the bottom of the U, where the zinc plug is.

If the coolant has been maintained, I wouldn't worry about the thermostats...if the flush resolves the issue on the port, I'd do the starboard at the next maintenance opportunity.

using the IR gun to verify the gauges would be prudent....as would taking other data points as well...and note the inlet water temp as the others will vary along with it...
 
How much do you dilute the muriatic acid? I believe that the full strength used in pools is 31%. How long do you leave the acid in the U?

Thanks,
Barry
 
There are several posts on the subject....and many variables.....

Depending on the concentration you start with, some will dilute it 50-50, some will go to 4:1 (H2O:HCl)...

It doesn't take long to 'consume' the zinc residue...5-10 minutes should be plenty...last time I did it, you could hear the fizzing stop...

Just make sure you rinse the cooler out afterwards....
 
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