fuel leak, engine bilge

[JohnNorton]

I've been intermintently seeing small amounts of diesel in my engine bilge. Placed blue indicator towels in and around many place this could be coming from, still have not find the source. Suggestions welcome.

[Richard Ad]

John: are you sure it's fuel? I've had an issue with engine anti-freeze leaking into my engine bilge every winter; and absolutely NO leaking in the warmer sailing season. My expansion reservoir is nearly empty in the spring. I replaced the hose and even removed the expansion tank but can't find where the leak is coming from. Next year I'm going to replace the plastic expansion tank to see if that fixes my leak. Come spring I give the bilge a good cleaning, fill the expansion tank and all is good for the sailing season. Good luck.

[JohnNorton]

A belated update to "fuel leak": not fuel, it is anitfreeze. I say "is" as still is; a small leak into bilge after engine cools. I finally purchased a tool to pressurize the cooling system. At 14 lbs.pressure overnight approx 2 oz. of fluid was in the engine bilge and pressure down to 10 lbs. I have not been able to find the source of the fluid, checking many times, checking and tightening hoses; mirror, paper towels, etc.
My greatest concern is a cylinder head issue; a cracked head gasket or worse, a cracked head. I annually send oil for lab testing and there has been small amounts (1-3%) antifreeze in the oil sample, never a milky appearance. Perhaps I damaged the head when I once neglected to open the sea water inlet; overheating buzzer went off, immediatly opened valve, engine back to 165 deg right away- did I do damage ? Perhaps yes. Anyone have experience with this ?
Coolant system pressure test showed a drop from 14 lbs to 10 lbs. overnight I am considering removing the head myself. Anyone done this ? Thanks- John

[leigh weiss]

before I pulled the head I would check under the cap of the cooling expansion tank on the exhaust manifold for the presence of bubbles when the engine is running and warmed up. The second place to look for a leak beyond all of the obvious places are the two bolts holding the alternator belt bracket to the block. One of these (the longer one) enters the cooling system and should be installed with sealant on the threads. This provides a very slow leak which is hard to find.
If you have to replace the head gasket, you can find a replacement kit for a Kubota V1305 engine (our engine) on EBAY for about $75.00
Upper Gasket Set With Head Gasket For Kubota, Bobcat, 16271-03310, V1305

The job takes about 2+ hours to disassemble the head leaving the intake and exhaust manifolds connected.
Remove the 4 injector lines and the glow plug buss to gain access to the head bolts.
Have the head checked for warping ( you might want to use a steel ruler to check ) and spend some time to clean the surfaces.
There is a silicone "O" ring that must be replaced on the oil fitting feeding the head. be sure to replace it with a new one.
Total reassembly time is about 2+ hours. Cleaning time will vary. You can paint the engine with Duplicolor SP403 VHT Titanium Siver Metallic Motor Engine Spray Paint Aerosol about $15.00 for 11 oz.
If you are working alone the hardest part is lifting the head off and replacing it. (Get a friend to help with these two jobs).
The owners manual has the head torque spects and tightening sequence.
Lots of luck tracking down the leak gremlin.

[TBOT422]

John,
By 'bilge' I assume you mean the pan directly beneath the engine. We have had maybe a 1/2 teaspoon of anti-freeze accumulate in this area as the engine cools. I found it to be coming from the weep hole under the pulley of the fresh water pump (not the raw water pump). The fresh water pump is the engine mounted pump that is turned by the alternator belt. There is a small weep hole under the pully. Anti-freeze can weep out of this hole and drip onto a short molded hose on the bottom of the pump. Ours eventually rotted out the small hose as the anti-freeze was absorbed by the reinforcing thread inside the hose. After replacing the hose, I installed a 'band-aid' made from a folded paper towel and electrical tape on the pump housing just above the hose to absorb any dripping. I replace the 'band-aid' on a regular basis as it becomes saturated with anti-freeze.

Good Luck

[Wisail]

Head gasket project sounds fun.
But I would do a fluorescent additive to the coolant, run to circulate. Then pressure check and use a light to show where the leak is coming from.
I assume you have checked the water heater exchanger and hosing as well as around the engine?
Then at least you know the head gasket work, milling, valves, bleeding fuel, is warranted.

[leigh weiss]

Gary and Janet,
You might consider replacing the water pump before things go from bad to ........
You can find this pump on EBAY for about $ 40.00
Water Pump Impeller 68MM Kubota 16251-73034, D1005, D1105, D905, V1305, V1505
I have replaced two on other boats and the job takes about 2 Hours start to finish. Most of the time spent replacing coolant.
The small hose on the bottom of the pump, the thermostat, expansion radiator cap and any other hose that looks bad should go in as well at this time.
Good luck.

Leigh

[JohnNorton]

Leigh: Thanks for your response. Tackled a schedule job this weekend; flushed/replaced the coolant. After filling I noticed I did have a bubble about every 8 seconds, one "burp". Don't know if this is air from coolant replacement procedure or....I did need to bleed air at water heater and at thermostat for thermostat to work; perhaps misc. air in system was source of bubbling ?? Did not check for bubbles after this; need to check this out again with a cooler engine.
I did pressurise the system to 15 lbs, no visible coolant leak (also removed valve cover at this time- no visible leaking there). Pressure loss was too slow to observe (like watching an hour hand move) but overnight pressure was lost and perhaps 1/2 oz. of coolant was in engine bilge; so an "external" leak is certainly causing or contributing to pressure loss vrs leaking internally into engine oil. Hopefully that's all, if not...

Your head removal advice is appreciated. If I do this looks like I'll also need to remove the valve rocker arm, re-adjust valves upon re-assembly. First I'll check the alternator bolt (wouldn't that be nice !). After running new oil in engine some hours I'll send another oil sample out for analysis. Whatever is happening it does not discolor oil nor do we observe white smoke in exhaust; only evidence has been in oil analysis.
Thanks- John

[leigh weiss]

John,
Yes, you should readjust the valve clearance after the re-torque of the head bolts. . Hope your oil is clean!!!
Valve adjust on cold engine.
Use sealer on alt. bracket bolts and tighten. I don't know the torque for these bolts, but you might find that for the size and pitch of the bolt on the web.
Keep us posted.
Did you find all the parts you need on ebay ?
You might want to test the water pump when you have the belt off. Just spin the pulley and feel for roughness and listen for noise.This would be a good time to change it and the small hose located on the bottom of the pump. About $40 on ebay , and add .5 hour to the job.

Leigh

[JohnNorton]

Coolant leak update No 2: Finally found source: A small almost pin-hole leak at the neck of the radiator cap assembly on the header, right above the overflow line connection. Found it by putting a light in the fill neck, sealing off the light so the only emission would be through a hole- and voila; there it was, at the connection. Bad soldering by manufacturer ?
I had been talking to Kubota service people about the antifreeze in my oil and the small amount (.25 to 1.5%) was not a concern to them; advised to change oil frequently- not remove the head as the amount was so small, not likely a head issue.
It seems after engine shut down as pressure from heat builds up in the system the pressure spring in the cap releases antifreeze toward the overflow tank. This starts the leaking I had observed for so darned long (through the pin-hole). This then spreads the antifreeze indiscrimently onto the engine. I never saw the leaking as engine was running, this happened only after shut-down. In a short time the header is apparently hot enough to dry up coolant on it, I never saw the leaking from the pinhole. But---- How then does the antifreeze get into the engine oil ? A puzzle of sorts at this point- if that was indeed the source of the contamination. I'll continue to change oil frequently, send for analysis.
Anyway, small application of JB Weld fixed the leak nicely.
Hope this helps someone down the line.

[wolfe10]

You are correct.

A coolant leak from the filler neck (i.e. external to the engine) is not related to coolant contamination in the engine oil.

I would change oil, run it for a hundred hours or so and have an oil sample tested again.

[JohnNorton]

Update to antifreeze in my engine oil: Thinking I had a head issue (crack or gasket or..) I was ready to take the head off. This after trying a radiator pressure testing device on the coolant system. Pressure held so. #@#!! ???. Leaving the boat one night I had an "flash of an idea"- somewhat literally. With all lights out I placed a flashlight where the cap goes and voila- light coming from a small hole in the fill section just above the overflow hose connection. This had been spilling coolant onto my engine for some time. JB Welded the hole, changed oil twice, sent sample for analysis- and zero antifreeze in the oil. Do not know how it was getting into engine from this persistent leak but seems fixing the small hole resolved my problem. I think I never saw the leak as it only leaked after shutting down the engine, heat building up expanding the coolant which is supposed to go to the expansion tank but instead leaked onto exhaust manifold where it dried up before I saw it's source point. When at running temp this hole never leaked as it's just beyond the radiator cap pressure ring.

[JohnNorton]

Sorry for the redundancy- did not read my earlier post- but oil sampling confirmed problem resolved.