Engine Over heating

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barnes01

Engine Over heating

Post by barnes01 »

My engine temp stayed constant at 160 for the past 4 years. It suddenly creeped up to 180 ... then to 210. I discovered the recovery tank hose had ruptured and I thought caused the problem. I replaced the hose and added coolant and filled the recovery tank to just above the add mark and started the engine. I bled what I thought was the last bit of air using the valve by the thermostat housing. The problem continued. I am assuming there is air somewhere in the cooling system and cannot seem to get it out. I read the Universal manual about a bleeder valve on the heat exchanger but could not locate. Has anyone experience this and what was the resolution?
djones
Posts: 36
Joined: Tue Jan 22, 2008 7:03 pm
Location: Oak Island / Southport, NC

Re: Engine Over heating

Post by djones »

There is another bleeder valve back on the fresh water heater in the rear of the boat. This is where the two small hoses coming off of the thermostat housing go to. In my experience, you need to have the RPMs up a fair amount, say about 2000RPM for a few moments while letting air out of that rear valve. I had to repeat it a few times to get the air out.

It is also possible that you have a stuck themostat, but that is more rare.

Thanks,
Don Jones, #13 "Onatop"
Oak Island / Southport, NC
R.B.
Posts: 233
Joined: Fri Jan 20, 2006 2:04 pm
Location: Ontario, Canada

Re: Engine Over heating

Post by R.B. »

Also check the following:
1) make sure that you don't have anything stuck in your intake by the thru-hull
2) check your raw water pump for broken vanes and that it is pumping water
3) check your heat exchanger, no leaks and that water from your water pump is flowing through the exchanger
Ralph

WOLFHELM
C350 #342
Richard Ad
Posts: 58
Joined: Wed Apr 14, 2010 1:08 pm

Re: Engine Over heating

Post by Richard Ad »

My temperature gauge went up to 190-200F yesterday. Typical temperature is 170F. This was my first time out for the 2012 season. I had water coming out of the exhaust. Newly rebult Depco raw water pump last year so I left the impeller in during the winter. No leaks noted at heat exchanger or other water or coolant lines. After motoring back to dock (approx 25 minutes total engine running time) I turned on the hot water and there was NO hot water. I think there'd be hot water after running the engine for 25 minutes.

Did you solve your temperature issue? Can you share what you did to get your temperature back to the 170F+/- range?

Thanks.

Richard Ad
2005 C350 / #329
R.B.
Posts: 233
Joined: Fri Jan 20, 2006 2:04 pm
Location: Ontario, Canada

Re: Engine Over heating

Post by R.B. »

Sounds like you have a blockage somewhere, possibly a stuck thermostat or blocked heat exchanger. If you have a laser thermometer you can point it along the water system to see where the temp is not high enough or too high. If you don't have one or can't borrow one; if you are careful and the system is not too hot you can feel the hoses to sense the temperature and figure out where the hoses are not warm enough.
Ralph

WOLFHELM
C350 #342
jonnjones
Posts: 23
Joined: Tue Aug 02, 2011 3:19 pm
Location: Deale, Maryland, USA

Re: Engine Over heating

Post by jonnjones »

Since the cooling water is flowing, then it's probably the thermostat. An easy way to check is to remove it and see if that solves your overheating problem. If it does, then replace the old thermostat with a new one.

Jon Jones
S/V Wind Orchid
Hull #273
djones
Posts: 36
Joined: Tue Jan 22, 2008 7:03 pm
Location: Oak Island / Southport, NC

Re: Engine Over heating

Post by djones »

It is the fresh-water/antifreeze loop that heats the water in the heater. 1st thing to check is that you have full coolant level as viewed by removing the radiator cap (when cold!) Don't just trust the level in the overflow tank as an indication. Beyond that, as already suggested, check the thermostat.

Also, regarding the antifreeze loop. It is supposed to work as follows:
Engine coolant gets hot and expands, pushing out of the radiator cap up into the overflow tank. As it cools after shutdown, the coolant contracts, and pulls the fluid back in from the tank UNLESS there is an easier path, such as a leak in a hose, etc. where it will pull air back into the system instead of coolant. If your coolant level is low, it has escaped somewhere, either external, or internal to the engine. The small hose from the radiator cap to the overflow tank is known for being a weak link. Also check the hose connections back at the water heater for leaks as well.

Good luck!
Don Jones, #13 "Onatop" Oak Island/Southport, NC
Richard Ad
Posts: 58
Joined: Wed Apr 14, 2010 1:08 pm

Re: Engine Over heating

Post by Richard Ad »

May 3, 2012 Problem solved. I suspected that my engine was not really overheating when I watched the gauge go to 200F to 210F and the needle was jerky. Also the volt gauge only went to 11-12 volts and that needle was jerky too. Shot the maifold and thermostate housing with a thermometer gun and it only read 160F, so my engine was NOT over heating. Took the gauge cluster off the helm pedetal and used a volt meter to measure each wire and noticed the volts were 13.5 volts (engine off) and then was only 11 volts with engine started (engine on). We cleaned all the wires of any corrosion and only got a slight increase in the volts. THE PROBLEM: the ground wire was undersized; from the gauages to the terminal the wire was a 10 gauge wire and from the terminal (out) was was a smaller gauage wire. We replaced the undersized ground wire with a 10 gauge wire and got a 13.5 volts on the volt meter. After running the engine for 20 minutes the Temperature reads 160F to 170F. All my needles are steady and alram sounds a little crisper.

The real credit goes to Frank at Diversified Marine Services (Annapolis).
barnes01

Re: Engine Over heating

Post by barnes01 »

Hat's off to Ken Krawford who pointed me to Richard's post. My engine overheating issue is resolved!!!

My temp Gage has been climbing to 200, yet shooting the block with an infrared temp device read 160. Voltage Gage on pedestal would not register yet on the panel read just over 14 with the engine running. The tachometer would frequently act erratic.

After reading Richard's post, I pulled the pedestal panel off and checked the voltage. I was only getting 8.5 volts with the engine off and just 10.5 with the engine running. Checking the leads coming into the buss that links the wiring harness to the instruments, I found the full 12 volts. Although visual inspection appeared to suggest that no corrosion was present, pulling the ground wire from the buss revealed that it was in fact corroded. I cleaned off the lead and the buss receptacle and reassembled. Wah-la !!! The volt meter on the panel then read just over 12 volts. Starting the engine it showed just about 14 volts. The tach was steady and after running for about 30 min the temp was rock steady at 165 degrees as it has been for the past years. As it has always been fine prior to this, I did not see the wire gage being a problem and therefore did not pursue replacing the ground wire.

Thanks again to Ken who first suspected a bad ground and for pointing me to Richard's post. Thanks also to Warren Pandy at Catalina who I spoke with about the problem as I was working on it and who indicated how leads may appear fine but actually corroded when inspected closely and of course thanks to Richard for posting his experience. I am happy once again. :D
Air Mobility
Posts: 47
Joined: Sun Apr 01, 2007 7:57 pm

Re: Engine Over heating

Post by Air Mobility »

I cancelled a one week cruise late in June because I noted a pegged out engine temp gauge 15 minutes after leaving the slip in Rock Hall. I later realized I had heard no aural alarm with the gauge reading high. I shut the engine done, raised the genoa and checked a few obvious things(engine raw water strainer and raw water impeller). After reading this string and testing the aural alarm, checking the gauge, wiring connections and grounds, I reworked all wiring connections, replaced the sending unit, thermostat and finally the gauge. The gauge was the problem. It tested good per Catalina proceedures, but it had an internal fault. The agrivating part of this is that everything had tested good, but I continued to get the overtemp after the engine and gauge had warmed up. It wasn't untill I changed the gauge that had tested good previously, that I again got normal readings(175 degrees).

George
Air Mobility
Hull 158
dpaulo
Posts: 22
Joined: Thu Jul 05, 2007 6:24 am

Re: Engine Over heating

Post by dpaulo »

I d hate t ask a stupid question, but..........is it possible to use an auto parts store off the shelf replacement thermostat
(of course set for 160F) or must I order from Universal/Westerbeke?

Thanks for any input.

Dan
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