600 hp cat running warmer

[algdog]

I have a 600 cat 3176 with 2100 hrs. no problems
last three weeks the motor is running 5 degrees warmer 199*F
questioned the mechanic he says water is warmer may be running warmer. I am running straight cat coolant, per cat recommendations

here is the question, do any of you guys running in warmer climates alter your antifreeze in warmer water conditions.

mechanic said to run straight water with conditioner no antifreeze

do any of you do this during your hotter water temp seasons?

I can not see this being the problem water is only averaging 76-79 locally lately. but who knows

[seapower]

I don't know what the ambient water temp was earlier, but the mid 70's is good. I myself would start the usual trouble shooting. Start with the simpliest first. Has the boat been sitting for any time? Around here it doesn't take long for intake scoop's to get growth on them, causing a restriction. The prop's get growth on the increasing load. Impeller condition obviously, sea water pump wear, a blockage anywhere in the system (old zinc piece's, old impeller pieces etc...). Most of the time it's something simple, you just have to dig and find it. Frank

[hotshot1]

How much of an issue is it if one engine does run a little hotter then the other

[algdog]

I don't know what the ambient water temp was earlier, but the mid 70's is good. I myself would start the usual trouble shooting. Start with the simpliest first. Has the boat been sitting for any time? Around here it doesn't take long for intake scoop's to get growth on them, causing a restriction. The prop's get growth on the increasing load. Impeller condition obviously, sea water pump wear, a blockage anywhere in the system (old zinc piece's, old impeller pieces etc...). Most of the time it's something simple, you just have to dig and find it. Frank

thanks for the response frank
all of that has been done. impellers changed every spring, zinks twice a year, strainer and then the hoses were purged backwards with no blockages found, it is moving alot of water
the question about running the straight cat antifreeze or water with conditioner and a 5 degree increase in operating temps

[seapower]

I've alway's used 50/50 mix coolant. I would be leary of using straight water. If the ambient water temp is in the mid 70's, I wouldn't think that would be necessary. Coolant does more than transfer heat. It lubricate's your pump and help's with pitting of your liner's. If it were me, I would verify the actual temp with what you're seeing on the gauge, before I went any further. Have you actually pulled the impeller since this event, inspected the interior of the pump, wear plate's cam, etc...? Raw water pump body's do wear with time. Again make sure there are no blockage's throughout the system. Have you had the heat exchanger servived? Scale build's up (on both the raw water and coolant side of the tube's) and there is a loss of flow and heat transfer. You can't just look at the overboard discharge and tell if there is enough raw water flow. Having a clear flow is something you have to know, no assumption's. Frank

[craigwill201]

the 1st to clog is the gear oil cooler. What I do on my 3208 is to pull the zincs out and remove the zincs from the plug. replace the plug then remove one of the raw water hoses and pour (I know some will not like this) diluted (50/50) muriatic acid down the hose. let this sit for 5 min?? and reattach the hose start the engine to flush.
ps when Gregory Poole cleaned my heat exchanger core the soaked in a diluted acid.