Generator overheats/shuts down

[trendycat]

Just had a number of items done to our Bird by Tim at Suncoast in Byron, Ga and everything was terrific (more details and photos in another thread). Left there Saturday morning and were traveling down the road when we started the generator to run the roof airs.

Everything seemed fine for about 30 min. - we pulled into a rest area for lunch, had sat for about 15 min when the generator suddenly shut down. Checked the coolant temperature gauge and it was pegged at the highest setting. Went outside and there was coolant running in a steady stream from the compartment.

Decided to wait to check things out until we got to the Mid-South RV park in Tunica, MS. Rained steadily since we got here so didn't get a chance to look until this morning.

Refilled coolant, started generator. Ran fine for about five minutes then the temperature gauge shot up to the max and the generator shut off. Coolant then ran in a steady stream from the overflow bottle until the bottle was empty. The coolant running from the bottle was not even warm.

My guess is that the coolant is somehow not circulating through the engine causing the overheat/shut down. Is it possible that a water pump has failed or that there is some blockage in the radiator itself?

This is a Powertech generator that is original to the bird and has about 5300 hours on it.

Any and all suggestions are welcomed along with any ideas for a good service center somewhere in the Memphis area would be appreciated. (We can travel for service elsewhere, if necessary, it'll just be a hot trip without the ability to run the air.)

Thanks,
Bruce

[pgchd]

Utilizing the keep it simple process, is the fan belt bad and not turning the water pump???(under the shroud in the front of the generator, hard to see) Is the thermostat frozen closed???? Sounds like one of the 2 with the symptoms you provided.

[trendycat]

I think the fan belt was turning but I'll double check that. Do you know where the thermostat is located? I'll give it a whack (the tried and true repair method for sticky parts) if I know what to hit.

Bruce

[Bill Pape]

I am not familiar with your Power Tech, But sometimes it is difficult to just add coolant , and get all the air out of the system. This is more than something simply, is the cooling fan running???

[pgchd]

Yes, try the simple things first, then "ratchet up"....... check the belt, see if the water pump weep hole is wet, pulley ok, etc. On the top of the engine follow the hose, there is a "thermostat" housing with an air bleeder valve........if coolant is low, add fluid from the cap on top of the engine, not the overflow tank......open the bleeder valve and let it "weep"......most of the air will purge, it is gravity designed..........worse case pull the thermostat out and run without one as a "try"......... these things run very cool on this model.......
PS these things "drain" at the radiator spigot down at the lower roadside compartment where the radiator is but "fill" at the top of the engine at the radiator cap tank.....letting the air bleeder weep purges enough air to get you going..............then after a run cool down period usually takes a quart or so. From your description of puking cold fluid, air lock not withstanding sounds like a frozen thermostat in the closed position or a frozen busted impeller on the water pump as a SWAG>>>>>> as stated above make sure the cooling fan over the radiator is spinning as well....as you may now have different symptoms, meaning the cooling fan was broke, boiled the coolant out, now the themostat is frozen........etc

[trendycat]

I checked the squirrel cage cooling fan over the radiator and it was working fine. Can't really see the all pulleys behind the shield, but the belt seems to be spinning all the ones I can see. Refilled the coolant, allowed to bleed through the valve on top of the thermostat, gave the thermostat a couple of good whacks with a rubber mallet.

Been running for the past 15 minutes with no apparent problems. Perhaps air or a stuck thermostat were the issues. Will monitor over the next few usages of the generator and hope for no more problems.

Thanks for all of the suggestions - looks like this gremlin has left for now.

Bruce

[peteaeonix]

What you describe exactly matches the initial symptoms I had when the electric motor quit turning the squirrel cage fan. This is, by far, one of the most common issues with the generator at about the age of our coaches.

The fan (which runs on 220 VAC) does not kick in until the generator is putting out electricity. Starting from cold, the generator will run for about 1/2 hour, then the safety system shuts down the generator to "save" it from overheating. While hot, a restart (after a brief period) will usually only let the generator run for 5 minutes more or less until the shut down repeats.

The only difference (in you symptoms) is that you've had some (probably secondary) problems occur with the cooling system. Unless the water pump seized up (due to the overheating) it's uncommon for such cooling system troubles to occur due to the fan not running.

The easy way to check the fan is to start the generator (while cold), wait the couple minutes until the power kicks on, then look at the fan. If it is not turning, the motor is probably worn out.

I found a company that specialized in ventilating and air conditioning vents fans and motors (for large buildings) that was able to match the motor with a new one (the OEM unit is long out of production). Some folks have done the motor replacement themselves, but I removed the shroud and fan/motor assembly and let the vendor install the motor and rebalance the fan.

The generator safety system should have shut down the generator before there was any damage or even loss of coolant. But as with any such system, the sensor(s) may have allowed it to run longer than it should have, causing loss of coolant and some of the other issues you're having. Or, frequent attempts to restart may have boiled off coolant. (Assuming you didn't initially understand the potential for the loss of the fan.) Or, secondary damage might have occurred, such as a water pump failure.

As for the "hot trip" you have my sympathy. My generator fan failed while I was in central Oregon in late spring. I travelled from Grants Pass to the SF Bay Area (down I-5 through California's Central Valley) and I'm only thankful that it was 80s "spring" weather rather than the triple digit summer weather common in the valley.

Running the Kool-O-Matic fan and keeping the window by the driver open helped keep the temperature tolerable. Note, make sure you empty your holding tanks, and then put a double or triple dose of deodorant into the black tank (and a dose in the gray one, too) as open windows and vents can cause vent odors to be drawn back into the coach. (My experience wasn't bad, in that regard, but conditions can vary.)

PowerTech is located in Florida, but they have authorized service centers across the country. While PowerTech generators are uncommon in RVs, they're used in a wide variety of emergency response vehicles (e.g. fire trucks). The PowerTech generator line focuses on larger (<10kw) units, so most RVs use Onan and other brands that fall into the 3 to 10kw output range. Web site is http://www.powertech-gen.com

Clicking on the "Parts and Service" link (left side box under Information), there's a service provider in Memphis: Generator Power Systems, 292 E. Mallory Av, Memphis, TN 38119. Phone: 901-775-1204, contact Ivan (ivan@generatorpowersystems.com)

[trendycat]

Pete,

Thanks for the detailed reply. My squirrel cage fan appears to be running properly at this point, but I'll watch closely for the symptoms of failure that you described. They follow very closely my experience on Saturday (when I forgot to check and see if the fan was running.) I have checked today and it seemed to be running fine, but it is also much cooler and I'm not driving so temperature and vibration may play a role.

I'll keep a close eye on this and see if it crops up as a problem again. Your links to the PowerTech site and their list of service centers could be very useful if I have problems again.

Bruce

[LarryKehler]

From my experience with PowerTech service centers - I tried two when my new to me bird's generator was not working- I would highly recommend that if you have a major problem with a PowerTech generator, go to the factory in Florida.

One center told methat Powertech was a bad company and tried to sell me a different brand after 15 minutes of testing. The other center told me that they would not even check my unit because they did not have any manual or parts.

I went to the factory and they put in a new head and checked everything else and charged a reasonable cost. I told them about the service centers I had gone to and suggested that they should remove then from their list.
Their reply was they need them for sales.

While I was at the plant, I talked to several truckers that were there for service to their units and they said they always come to the plant for any service because they really know what is right for the units.

New motor idling laws require that truckers not idle engines for more than a few minutes so most over the road trucks now have generators to run air and heat. PowerTech has a big share of that business.

Next time I have any problem with my generator, I will head for Leesburg, Florida.
They also have hookups. I stayed around for an extra night to make sure all was running well before leaving.

[joe40king]

When I replaced several feet of radiator hose for leaks there was air in my system. I opened the petcock like Randy told me and even though it ran fine the first time I had to go in and pull one of the return hoses(which Randy also told me) and fill it too. I did this procedure three times if I remember to get the air out and primed right...It is a simple thing once you look in the right place. Thought I had a stuck thermostat and everything else under sun but ended up being air in lines....JOE sends