generator shut down

[tskrodzki]

We have a 2000 XL2 LeMirage with a Kubota generator. Today I started the generator up to use the house A/C to cool off the bus before our trip and after 15-20 minutes the generator shut down by itself. I checked the gauges and the water temp spiked to 245 degrees. I opened the generator bay and slid out the generator which was steaming a spitting out antifreeze. I could see anything visually wrong and the blower fan behind it was spinning. Any thoughts? Thank you

[JIM KELLER]

This much information is to limited for me to help. The good thing is a overheat sensor shut it down before damage could be done. Let it cool down and determine if you are low on coolant, if the cooling fan is working, is the alt/water pump belt in place etc. Bring us up to date and someone will jump in to help.

[tskrodzki]

Coolant levels are full, blower fan is working and the belts are all in tact. But after 10 minutes the water temp starts to climb so I turned it off.

[Pete]

All of what Jim said. In addition, you failed to mention whether the oil was checked, as the gen will shut down on oil pressure.
I would suspect the thermostat, or a clogged radiator. When was the radiator last rodded out and cleaned?
Please post the converter of your coach as it would help us assist you. Different converters locate the cooling radiator in different locations. Some are located in the generator bay, some on the roof of the coach, some in a different location which are not visable. More information would help.

[AmeriStar]

Sounds like. at the very least, your engine overheated and blew a head gasket. In a Kabota this is very common.
First determine why the engine overheated to begin with. A clogged radiator, blocked intake screen, failed cooling fan, are the most common culprits.
After this is determined, address your engine. You will need to remove the head and inspect the cylinder walls for scoring.
If you find scored cylinders, the block will need to be honed and new rings, pistons, head gasket, and aux gaskets installed.
Plan on a overhaul bill (if genuine Kabota parts are used) of 2500 to 3500 dollars (not including the time to remove the genset from the bus). The are less expensive aftermarket kits, you make the determination.
We have had 3 buses stop at our shop with failed gensets this summer. ALL have required an overhaul. This hot summer is finding all of the weak points.

[tommybahama96]

Same thing happened to me six weeks ago on a 100+ degree Oklahoma Panhandle day. The Kohler Powertec Generator shut down, there was a strong odor of boiling coolant and clouds of steam came out of the bay when I opened it. The opinion of various local Detroit Diesel, Cummins, and Kohler mechanics, who were committed weeks in the future and couldn't take it on, was low coolant. In our case the radiator was remote from the Kubota engine. When I topped it off with coolant, I thought it was full. Wrong, actually. The line may have an air pocket that will stop coolant from flowing to the engine.

The bottom line? It got so hot the Kubota's seals melted, spilling oil. Now I need a new or re-manufactured Kubota. Kevin, one mechanic discouraged reworking the damaged block; thought it could turn out to be a nightmare.

[merle&louise]

David,

You said that it got so hot it melted the seals; did you notice how hot it reached in degrees? 225+ ?

I have a 20 KW Kohler and it has run at 225 degrees this summer. It hasn't shut down, but I just wanted to know how close I was to a melt-down!

[tskrodzki]

Thank you all for the reply's - @Pete it is a Vulcan conversion, looks like the radiator is in the Gen bay behind the generator not easy to get to, I did check the oil and it was full as well. @Ameristar - Head gasket sounds like bad news, I was hoping for a bad water pump. Looks like I will need to get a diesel mechanic out to look at it. @Merle mine was around 245 or so.

[gmcbuffalo]

Have you had any work done on the unit that would require a coolant change? I any thinking check for an air lock in the cooling system. Since you found out where the radiator is now check to make sure the fan is working on it and check the temp of the radiator compared to the engine. Are they both getting close to 245 Degs. If the radiator is not as hot as the engine, coolant is not flowing (air lock or plugged radiator). You don't need to wait until it is 245 to find this out so shut down the generator before that temp. If these don't help you have engine problems.

[AmeriStar]

David,
It depends on the severity of the damage. Kubotas are very durable motor and this happens often in the Bobcat skid steer loaders. We did an exchange in our shop for a customer and the Kubota Reman exchange cost was $5900.00 plus 30 hours of shop labor for pulling the gen, changeing the motor and reinstalling. The bill was just short of 10k.
A rework of the block and everything involved is about 4k.

[tommybahama96]

Kevin - Thanks for letting me know what I'm in for. Yikes! c. $10K to replace with a re-manufactured engine. We'll look at reworking the burned one.

Ironic, there's a new 21Kw Mitsubishi on eBay for $7,500.

http://www.ebay.com/itm/21-5kw-Diesel-Generator-Mitsubishi-/270924912027?hash=item3f1462159b&item=270924912027&pt=Motors_RV_Trailer_Camper_Parts_Accessories&vxp=mtr

[tommybahama96]

Tuga - I'm thinking it should get much hotter than 245 for the seals to melt. I would be concerned if the temp reading is off the gauge's scale. My engine's coolant completely boiled off through a melted bleeder tube. It got so hot that engine oil drained out melted seals. Oil smelled burnt. Mechanic said I was just around the corner from a fire in the bay.

[AmeriStar]

The Power Tech manual states that an ideal operating temp is between 180 and 195. The max temp should not exceed 235.
These guidelines are for the Kubota powered 17.5 KW and 20.0 KW gensets of the late 90's early 2000's vintage.
The correct thermostat for these applications is 180 degrees.
Understand that the electric fan setup's that most Prevost conversions have, pulls air thru the generator engine compartment and radiator and pushes it out the bottom of most coaches.
KEEP YOUR INTAKE FILTERS CLEAN! It is very easy to 'plug' your intake filter on dusty dry or rain soaked roads.

[tskrodzki]

To update: Somehow an air lock happened causing the generator to overheat and shut down, I had to top of coolant let it run for 10-15 minutes shut it down and top it off again. Did this 3-4 times until the coolant level didn't drop. Installed a thermostat (since there wasn't one in the unit) and have been running around 175-180 degrees with no more problems. A gentlemen by the Name of Steve Fudge from TN (an expert with these generators) walked me through what to do over the phone.

[Gary Carmichael]

Mr T, How many hours does your gen set have on it? and is it original to the coach? Gary