CAT 3196 Coolant leak?

Russ Calasant

Russ Calasant

Active Member
Dec 9, 2009
2,128
East Greenwich, RI
Boat Info
2001 480 DB
Engines
CAT 3196
During “spring” commissioning it was noticed that the port coolant overflow tank was empty. A mechanic used a pump to fill the expansion tank directly and then added to the overflow- less than a gallon total. A 20 minute warm up at the dock and a trip below a short time later yielded an empty overflow again- a couple quarts. I added about 3/4 gallon to the overflow, ran for 20, shut down and watched the coolant slowly being drawn up the tube to the tank and maybe a quart taken. There is no evidence of coolant in the bilge, smell in the exhaust or steam and oil looks normal. Oil `samples were done last spring with no evidence and I do not recall any coolant loss last season. Thoughts? -thanks
 
Have you pulled the heat exchanger. Possibly leaking out into raw water?
 
If it's leaking out of the heat exchanger, warm up the engine, turn it off, let it sit 10 minutes, when you go to start it up. have some one watch the water exhaust, if its leaking you will see it.
 
Warm the engine up and pull an oil sample and a coolant sample and have Cat run their SOS analysis on both (kits are available from your Cat dealer for about $14ea). The results will show combustion by-products in the coolant or coolant in the lube oil which will help you rule out a head gasket leak.

Losing this much coolant certainly points toward a heat exchanger leak……………….or a leak in the boat you haven't considered like the water heater heat exchanger leaking int oa bilge compartment no where near the engine.
 
fwebster said:
Warm the engine up and pull an oil sample and a coolant sample and have Cat run their SOS analysis on both (kits are available from your Cat dealer for about $14ea). The results will show combustion by-products in the coolant or coolant in the lube oil which will help you rule out a head gasket leak.

Losing this much coolant certainly points toward a heat exchanger leak……………….or a leak in the boat you haven't considered like the water heater heat exchanger leaking int oa bilge compartment no where near the engine.
Click to expand...
Hi Frank, I ordered the kits and will pick them up today - thank you. I will check but don’t believe my water heater is in the loop, didn’t think about it and will scour the bilges and lazzarete. I don’t suppose the fact the oil was just changed in the fall - few hours on it, matters?
 
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doozie said:
If it's leaking out of the heat exchanger, warm up the engine, turn it off, let it sit 10 minutes, when you go to start it up. have some one watch the water exhaust, if its leaking you will see it.
Click to expand...

I tried it and there is a “cloud” appears whitish in color and then dissipates. The ELC is red?
Overnight the level in the overflow dropped significantly, maybe a quart or so, today after running a couple times the level has remained the same. I can see an air buble in the overflow tube at the expansion tank filler cap, coolant is not moving. Yesterday it was being drawn in after shut down.
 
Cat ELC is red.

Have you drained or chanced the coolant recently?

On some engines it takes several warm up - cool down cycles to purge the trapped air from the cooling system, but you have added more coolant than normal for that to be the cause.
 
Anyone know what is entailed with pulling and replacing the heat exchanger? A job for a mechanic or for someone reasonably inclined - without experience with HE?
 
fwebster said:
Cat ELC is red.

Have you drained or chanced the coolant recently?

On some engines it takes several warm up - cool down cycles to purge the trapped air from the cooling system, but you have added more coolant than normal for that to be the cause.
Click to expand...

I have not done either.
 
I've worked on those engines on the same boat, if it is on the outboard side of the engine, it's gonna be tough. Either way it just a lot bolts and brackets to remove and tight quarters.
 
doozie said:
I've worked on those engines on the same boat, if it is on the outboard side of the engine, it's gonna be tough. Either way it just a lot bolts and brackets to remove and tight quarters.
Click to expand...
I think the bundle slides out of either side - but it’s the port motor
 
I had a similar problem. Took forever to find the missing coolant. The hose to the heater/defroster had a pin hole or two. Might be worth looking at. Was one of the only easy fixes I ever had. LOL GOD bless. JC
 
JC3 said:
I had a similar problem. Took forever to find the missing coolant. The hose to the heater/defroster had a pin hole or two. Might be worth looking at. Was one of the only easy fixes I ever had. LOL GOD bless. JC
Click to expand...
You had a cockpit heater/defroster that had a leak? I don’t have anything else on the closed cooling loop-
 
doozie said:
I've worked on those engines on the same boat, if it is on the outboard side of the engine, it's gonna be tough. Either way it just a lot bolts and brackets to remove and tight quarters.
Click to expand...
Is it correct that the bundle only slides out in one direction? So the exchanger on one motor has to come off and the other can slide out? Do you know which way the bundle slides?
 
doozie said:
I was thinking of mine, your right, I don't remember which way they came out, was a couple of years ago
Click to expand...
Ah - ok, I did just talk to someone that has the same boat/Power and has removed them, he said port will slide out to starboard and the starboard side requires removal. Thanks for your help-
 
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