8v53 RUNNING HOT

[Boatsb]

While idling back from a day at the island I noticed one engine at 190+ degrees. At 900, RPM no less. It was shut down for the rest of the run back but started again to dock where it went up to 190 again. water flow may be the issue but the HE was acid cleaned a few months ago and the other engine which was not done then is running cooler.

I will pull the strainer, Check the zincs and check the coolant level this weekend but I am looking for anyone with experiance with this who may have another place to look.

FYI I did think about the belts. I will check them too.

Any suggestions?

[jim rosenthal]

Fresh water (coolant) side: sticking thermostat, circulating pump not working, hoses, air in system; no doubt people can come up with a few more at least

Sea water side: impeller, collapsed hoses, something in strainer, clogged showerhead, pencil zincs that broke off and clogged the HE, seawater pump bad even if impeller is OK (wear plate, cam, etc)

There's also belts to worry about, and any hose in the system can collapse internally from delaminating and "pant", so that it looks okay outside but doesn't let enough water or coolant through.

Well, better now than in the middle of the season, anyway...let us know what you find.

[Boatsb]

Thanks Jim. I think you convinced me to pull the whole SW side off and clean it. Hose and all. The seawater pump is new last June with 50 hours on it so I think thats not the issue and I replaced all the zincs but the old ones were not there.

The showerheads are still abit of a mystery to me. I will hope for some more help from Karl there. Can I clean out the manifolds/shower heads without tearing too much down?

Oh and Jim By the way it is the middle of the season down here.

BTW hows the repower coming?

[shvldis]

Just got done with that project on port motor. We will be back down this comming weekend, give us a yell if you need a hand, Ill bring my IR gun so we can do some comparisons between engines.

[Genesis]

If you have a belt-drive raw water pump check that first. Check the impeller too.

If you're hitting 190 at idle you've got a very serious problem (like no raw water flow or no coolant flow at all!); Detroits will normally barely come to 150 at idle.

If you can SEE raw water flow in the exhaust its probably not there. I'd be very, very suspicious of the thermostats being stuck in "bypass".

Get out the IR gun and start looking around - this one should be easy to find since you can provoke it at idle.

[Nick]

Scott,

If the showerhead suddenly somehow got plugged , the hose dumping to it will have pressure built up in it as the raw water pump runs. The showerhead would have to be nearly completely fouled and you would have very little flow out the exhaust. You can start up the engine put your hand on the hose and check to see if the hose gets hard and there is flow at the exhaust. Not my first guess for the source of the overheat.

I pulled mine off and dipped it in muriatic to dissolve the build up I found in the raw water openings. I think my showerhead is stainless or monel.

Middle of the season Too bad.. Its almost the beginning of the season here

Nick

[Boatsb]

Well I think I have a slight leak in the cc system. I opened up the hatch and found a bout a gallon low in the heat exchanger and that is a bit much BUT I must admit I have 20 hours since I last checked it. ( my bad) The oils is clear of water, a nice Detroit black and showing no sign of rising.

I see some porosity in the pipes that attach to the hoses and I will double check and tighten the clamps but it is an original 1966 engine that has some corrosion on the outside. I filled the HE and could not get to 130 degrees at the dock.

Is there anything I can add like a radiator sealer that will help seal the brass/bronze pipes and not hurt anything else? I was thinking of adding this as a stopgap as I cant afford to tear it down to re pipe and hose it since the parts from Detroit are somewhere around $1K for the hard parts plus gaskets, hoses and labor.

[REBrueckner]

Next time you start the engine and while it is warming, check for coolant leaks while pressure is rising as coolant is getting hotter: hoses, clamps, radiator cap, pump, gaskets, etc. Snug up all hose clamps. If a brass/bronze coolant pipe is dripping, you can solder the hole after draining coolant. You can also place some paper towels under the engine to see where coolant might be dripping. (Oil and transmission oil are clear of water.) If you don't find any external leaks, then likely a heat exchanger or fuel cooler is leaking...coolant is going into your exhaust....you'll have to remove them and have them pressure tested.
Another option is to remove the radiator cap and get a pressure tester...pump to desired level..maybe 10 lbs and see if it holds....you will still have to search for a leak but at least its quiet when you do...

[NAN-PO 41]

Scott,
When I first bought my 41tc one of the first things I did was to pull the H/E cores and clean them in a 5 gal bucket of Ospho/Water. I didn't do that because I was so smart about Detroits but after seeing posts by Genesis about how important it was to do. I didn't want to do it with the cooling system together as I wanted to inspect the system components at the same time as the boat was new to me. I couldn't believe the amount of crap that was caught up in the exchanger cores. There was everything from small pieces of weed to chunks of old pencil zincs. My advice is to do a thorough cleaning job on the cooling system. It is really low cost insurance.
If you need any specs for the 8v53's ( such as torque etc. ) send me a PM and I can get them out to you.
Fred