Changing the coolant on my Cummins and while I'm at it planning on changing the coolant in the generator. I was running the generator and it starts, but continues to die after running for about 4-5 minutes. Where can I start to debug this? The service center that did the Cummins oil change also changed the oil, oil filter, and fuel filter on the generator. I'm wondering if there could be an issue with the fuel filter having air in it or not flowing correctly?
I would start with fuel supply issues. With a coach that age, the fuel supply line would be my first suspect. Try running with a fuel supply from a bucket direct from the fuel pump. If it runs smoothly uninterrupted, the fuel line replacement is in order.
Any fault lights? That's usually the best place to start.
And of course we have the handy sticky topic here
Generator Topics Recap (http://www.foreforums.com/index.php?topic=11804.0)
Where would the fault lights be? I'm beginning to think it might be overheating and shutting itself off. Maybe a thermostat?
I sat there and watched. When it shuts down, there is coolant coming out the overflow and if I pop the petcock on top of the engine (pictured), there is steam that flows out and the hose is very hot to the touch. The weird thing is the hose coming out of the bottom of the radiator is very cool to the touch. My guess is something is not allowing the coolant to circulate through the radiator. Any ideas on culprits or how to debug? Off the top of my head, could be air bubble, blockage in the radiator or hoses, or thermostat stuck shut?
I had that issue with my unit and it was a loose belt on the water pump/fan pulleys.
There are fault lights on the front of the generator itself. Sensors that can cause a fault and shut-down the generator included low coolant, high temperature, and low oil pressure. On mine the coolant level and temp are tied to one fault light (which confused the tech greatly, since the over-temp light was lit but the temp was ok) .
One more thing, the generator will run even if it is not producing any electricity. In this case, the cooling fan (electrically driven) will not run, and the generator will shut down for being over temperature.
Assuming the radiator fan is workng, antifreeze if up to proper level, I would be thinking thermostat not opening, However in your case I would be looking close at the fan. We have seen a very strange happening on a Kubota engine, where the engine was running fine but the water pump was not turning very fast, crankshaft pulley was slipping, needed new pulley on crankshaft. Just a thought on that one, very rare in my world.
A stuck thermostat will eventually make the bottom hose very hot too, why thinking fan issue.
Good luck
water pump toast?
fan not running?
Sounds like it's shutting down on overheat. I had the same issue with a 95 U320. The generator radiator is mounted vertically. They are prone to air pockets which cause the water pump to cavitate. There should be a small drain valve at the top of the radiator, crack it while the engine's running to allow the air to escape. Make sure to keep the coolant system full.
I had the same thing with mine (10kw like yours) and it was the fan not coming on like it was supposed to. The really good news is that the genset cut off. If it didn't you would be buying an new one. This generator is designed to cut off when it gets too hot (thank goodness). If fan is working and blowing well, check the hoses to make sure not kinked and belts intact. Mine seemed to do that as it slid in and out on the tray. If they are original hoses, I would recommend changing at your earliest convenience.
I have the same generator on mine. It was the fan, was not going on like it is supposed to do. Make sure it is on. If the fan is blowing well, look at the antifreeze, make sure full, I had an issue with the bracket holding the metal support that protected the belt mechanism. I had to take off and took to a welder to reweld the bracket as it was eating the belts. Another issue I thought may have been a problem was I was concerned about the rubber coolant hoses, I changed all of them as mine were about 15 years old. It may not be significant but I was concerned about the hoses kinking when I slid the genset in and out. I put another larger hose over where I thought the kink would occur and this rounded out the bend so there was no kink. Since that time all is A-OK. You may consider changing oil if it overheated too. I think a good idea.
Unfortunately, no fault lights that I can find anywhere on my genny. :-(
All, thanks so much for the suggestions. I was tied up with the coolant change on the Cummins and had to get that done before dark otherwise I'd have been stuck in front of my buddies house! I don't KNOW FOR SURE that it's overheating, but that is my guess given the steam from the petcock on top of the thermostat and radiator cap. I have a few questions WRT to your feedback...
1. The pic I posted of the petcock and what I'm assuming is the thermostat housing (correct?), is that hose the supply to engine or return to the radiator? It was hot to touch and the hose coming out of the bottom of the radiator wasn't even warm. Depending on the direction of water flow, that could possibly tell me something.
2. I'm a little confused on the radiator fan, belt, etc. It seems some of you imply that if the belt is slipping the radiator fan might not be cooling? My radiator is housed in a separate compartment and there is what looks to be an electric fan in that compartment that is for cooling the radiator. I can tell you that, that fan is kicking on.
3. So, what does the genny belt turn? Just the water pump or is there another fan behind that big shield?
4. How do I pull the shield off the side of the generator. I took a brief look and only saw two bolts, one looks to be part of the thermostat housing and the other is on a bracket. Is that it or is there one hiding behind?
5. I would also like to note, that the radiator hoses seem to be in good shape and fairly new. Don't look to be 15 years old IMHO.
"A stuck thermostat will eventually make the bottom hose very hot too, why thinking fan issue." - I was thinking about this. The first time I started it, it may have run for 10 minutes. The next time only 5 min. If the thermostat is stuck close but the cooling fan is running properly, I would think it would take some time to heat the water at the opposite end? I'm a newbie at this so feel free to poke holes in this logic also, it really depends on the coolant flow direction which I'm not sure how it flows.
I still suspect the fuel lines. If you start the genset tomorrow and it runs for 10 mins. then cuts off. Try to start it in 5 minis and see hoe long it runs. Once the fuel in the lines gets consummed, you start to get air into the fuel being injected to the cylinders. Try the fuel supply from a bucket with a hose from the suction side of the fuel pump. This way you can definitely rule out the fuel supply.
Peter, I'm only hesitant to do this because there was some serious steam coming out of the petcock when I opened it and the coolant expanded enough to start flowing out of the overflow. If it was a fuel problem, I wouldn't think the coolant would get hot enough to create that kind of steam since it should only be about 190 degrees?
I don't mind trying this to see if its the issue, but I'm also concerned about running the engine too much if the problem is overheating. Can't be too good for it. Thinking I may try changing the thermostat, check/tighten the belt, then bleed the radiator first. If that doesn't fix the problem, move on to fuel as that is the lesser of two evils.
I agree. If the engine overheats in just 10 minutes, then there is no coolant flow through the radiator. Then it's pump, thermostar, belt (if applicable). The board & temp. sensor seem okay it it's cutting-off fuel supply on overheat detection.
I was thinking about some of this last night as I was going to bed. I was on a slight incline on the street, in fact I tried leveling and the HWH gave me an excessive slope warning. I guess its possible that an air pocket could have formed causing the pump to cavitate. Anyone know about the following...
1. The pic I posted of the petcock and what I'm assuming is the thermostat housing (correct?), is that hose the supply to engine or return to the radiator? It was hot to touch and the hose coming out of the bottom of the radiator wasn't even warm. Depending on the direction of water flow, that could possibly tell me something.
2. I'm a little confused on the radiator fan, belt, etc. It seems some of you imply that if the belt is slipping the radiator fan might not be cooling? My radiator is housed in a separate compartment and there is what looks to be an electric fan in that compartment that is for cooling the radiator. I can tell you that, that fan is kicking on.
3. So, what does the genny belt turn? Just the water pump or is there another fan behind that big shield?
4. How do I pull the shield off the side of the generator. I took a brief look and only saw two bolts, one looks to be part of the thermostat housing and the other is on a bracket. Is that it or is there one hiding behind?
Is this an Isuzu engine?
Kubota
Best Regards,
Benjie
Benjie Zeller
(512) 587-4628
Not familiar with the Kubota, so not sure about the set up. Mine is a PT 8 KW with Isuzu, and the radiator is mounted with the engine along the sliding tray. Not a great set up due to vibration.
We have the 10K PowerTech with Kubota engine. The radiator fan is electric and is located in the small bay below the drivers seat. The fan blows air through the radiator at the rear of the bay and it is exhausted out the back of the bay near the driver side tire. The air is deflected away from the tire toward the passenger side.
One time I turned a switch off at the control box on the generator to see what would happen. The generator shut down in about five minutes. The switch controlled the electric fan. If the fan is not blowing copious amounts of air through the radiator and exhausting it under the coach, the generator will shut down quickly.
Benjie,
You have not confirmed that the generator is indeed making AC power. Is it? Also, have you bled the petcock at the top of the generator radiator?
Yes, making power. Headed to purchase a thermostat and new belt. Then to storage to bleed the radiator. Will advise progress!
Best Regards,
Benjie
Benjie Zeller
(512) 587-4628
Changed thermostat and belt. Also flushed and replaced coolant. It ran solid under load for 10 min. Unfortunately had to get home so hope to get an opportunity to run it longer this weekend!
Check to make sure the Fan is running. It needs power from the generator to run. If no fan, generator shuts done on overheat. Mine did that and the problem was the voltage regulator.
Benjie, you access the belt by pulling the generator out on the slides then crawling underneath and then schootching up behind it! You'll be able to see the belt and tensioner then. Good luck. If it's overheating then I wouldn't think it would be a fuel problem.
A few years ago I was getting ready to go on a 2 week trip. I fired up generator and let it run for about 10 minutes with both AC and then let it cool and shut down. Left early in morning on trip. Mid day started getting warm so fired up generator. After 15 minutes generator shut down. Restarted and only ran a minute. Next stop found out the electric fan had blown the circuit breaker. Stopped at autoparts and found parts to rig up a new fuse. After getting done the fan would still not run even thou it had power. Motor was a multi speed motor so figured I would try a different speed. Fan started but was a lower speed. Figured I then could use generator if I did not load up. Fan worked for about 15 minutes before it died again. Ended up finishing up trip without generator. Once back home had to replace complete fan & motor assembly.
I got to the belt, but I just pulled the genny out, then loosened the two bolts I could see (one on the thermostat, the other towards the bottom of the motor) on the shield. Tried pulling it off and discovered the third bolt was also the bottom of the tensioner pulley. Was able to get tools and hands in to just loosen that and then took the old belt off and replaced it with a new one. FYI, the Gates 7360 was too small, had to go all the way up to a 7370. Even that didn't fit until I fully removed the top bolt of the pulley and slid it past the guide!
I'll have to look again, but I'm almost positive my generator bay has no opening underneath, even when slid out. In fact, my buddy even commented on it asking me how you get back there if needed. I'm sure you can remove the cover, but since I didn't need to get behind it never really dug into it.
Thanks,
Benjie
The mechanic that replaced my oil pressure sending unit was small enough to climb in back, don't think I could ever have gotten back there.
On a 295 I am familiar with you can gain access to the back of the front mounted genny by removing the guard under the front of the coach, four bolts if I remember right. I had to do this to get to oil pressure switch.
Gary B
YEE HAW!!! Genny ran under load today for over an hour! Looks like thermostat, belt, or coolant was the contributing factor!