Community Forums

Full-Timers · 09-07-2017, 08:43 PM

Quote:

Originally Posted by AKIQPilot

So the two electric fans aren't really there to cool the engine. One is the AC condenser fan and the other is the transmission cooler fan. They are wired together and should come on together.
.

From the Workhorse Chassis Guide:
The electric condenser fan(s) also assists with engine cooling.

Also since both fans are side by side in front of the Transmission cooler which is in front of the AC Condenser, One can't be for the Transmission cooler while the other being for the AC Condenser. Both do the same job.

AKIQPilot · 09-07-2017, 09:31 PM

Quote:

Originally Posted by Full-Timers

From the Workhorse Chassis Guide:

The electric condenser fan(s) also assists with engine cooling.

Also since both fans are side by side in front of the Transmission cooler which is in front of the AC Condenser, One can't be for the Transmission cooler while the other being for the AC Condenser. Both do the same job.

Thanks for the clarification.

Full-Timers · 09-11-2017, 08:53 PM

Have you found a reason for the power loss yet?

RV Poppy · 09-11-2017, 10:53 PM

Ok. If one fan is for the A/C and the other for the transmission than why would they come on together. If I turn the A/C on it does not automatically mean that the transmission needs cooling but it is a given that as soon as I run the A/C one of the fans comes on. Even if the fan is for the transmission and not the engine could you loose power because the transmission is hot???

AKIQPilot · 09-12-2017, 12:07 AM

Quote:

Originally Posted by RV Poppy

Ok. If one fan is for the A/C and the other for the transmission than why would they come on together. If I turn the A/C on it does not automatically mean that the transmission needs cooling but it is a given that as soon as I run the A/C one of the fans comes on. Even if the fan is for the transmission and not the engine could you loose power because the transmission is hot???

Full-timer clarified how the fans work. I believe the ac condenser and trans cooler are stacked one behind the other. Both are in front of the radiator for sure. When the ac is turned on both fans should kick on. I believe the fans also kick on when the engine coolant reaches a certain temperature. I dont believe the transmission temperature ever turns the fans on.

I misspoke when i said one is for the ac and one is for the trans cooler.

The transmission never gets all that hot. Ive been monitoring my trans temp all summer. Pulling fairly heavy loads up some pretty steep hills. I never see over 150f without towing and over 170 while towing.

If youre transmission is getting hot, like over 250f, then something is likely wrong. I work the heck out of my Itasca giving it no mercy ever and the trans never goes above 200. Not even once.

Are you still having issues with losing power? Have you ever heard the big fan on the front of the engine kick on?

RV Poppy · 09-12-2017, 10:12 AM

I have waited to hear back from the original garage to ensure that they indeed change the fuel filter and they ensured me that they did. So for now I am ruling out O2 sensors, MAF, and fuel filter. I am pretty sure the big fan on the engine runs constantly. Since both fans run together in front of the radiator I now know that one must be bad. I am not sure that this is the issue because my temp gauge has never gone above normal. On the other hand, from previous posts, it seems that this is not always an accurate method to determine temp. Will work on the fan issue and go from there folks. Appreciate all your support and going to keep going at it.

AKIQPilot · 09-12-2017, 10:39 AM

Quote:

Originally Posted by RV Poppy

I have waited to hear back from the original garage to ensure that they indeed change the fuel filter and they ensured me that they did. So for now I am ruling out O2 sensors, MAF, and fuel filter. I am pretty sure the big fan on the engine runs constantly. Since both fans run together in front of the radiator I now know that one must be bad. I am not sure that this is the issue because my temp gauge has never gone above normal. On the other hand, from previous posts, it seems that this is not always an accurate method to determine temp. Will work on the fan issue and go from there folks. Appreciate all your support and going to keep going at it.

A couple of observations.
1. If you don't hear an obnoxiously loud roar from the engine fan then it's not coming on. When it first kicks in you can hear it mildly like your defrost fans on high. When going up a hill and it needs additional cooling the fan roars above all other noise in the entire motorhome. It's not possible to miss it. If your engine fan is on all the time (which I highly doubt or you would have started another thread here already about the loud noise under the hood) then it has a problem.

2. Your in-dash temp gauge is never reliable. From about 140f to 230f the gauge will read basically the same, right in the middle or slightly under. Some people have reported that their engine completely over heated and boiled coolant out and the in-dash gauge never went above normal.

3. You seem reluctant to get yourself a Scan Gauge or some other OBD2 compliant gauge so that you can monitor your engine and transmission parameters. This thread is a few weeks old now and you could have had a scangauge to your door in 3 days. A scangauge isn't going to do what a high quality Scan Tool (in the hands of a trained technician) does but it will give you lots of things to look at and you may be able to rule out things that are not your problem.

And lastly. Are you still losing power after just a few miles or minutes of driving and going up hills? I thought earlier you said things were better after the tech reset the CEL codes?

RV Poppy · 09-12-2017, 11:09 AM

I have already stated that the CE light did not come back on since the last time I had it read and reset by a "qualified technician". I also stated that although it ran much better it still seemed to bog down here and there going up the mountains. The fan may have came on but I may have mistaken the roar for that of the engine or transmission. I have no problem getting a gauge but if more than one "qualified technician" has not figured it out than I doubt I can. I started this thread to try and get some troubleshooting advice from both those with more mechanical knowledge and more RV experience. I dont get a chance to mess with it every day and didnt know there was an expiration date for threads. I have already put 2000.00 into this thing this year and it has been in the shop for 2 1/2 months this camping season. I was just trying to take in all suggestions and hoped to avoid another high price ticket. Anyway, I do appreciate all advice but following this thread or replying to it is ones own choice. Thanks

AKIQPilot · 09-12-2017, 12:42 PM

Quote:

Originally Posted by RV Poppy

I have already stated that the CE light did not come back on since the last time I had it read and reset by a "qualified technician". I also stated that although it ran much better it still seemed to bog down here and there going up the mountains. The fan may have came on but I may have mistaken the roar for that of the engine or transmission. I have no problem getting a gauge but if more than one "qualified technician" has not figured it out than I doubt I can. I started this thread to try and get some troubleshooting advice from both those with more mechanical knowledge and more RV experience. I dont get a chance to mess with it every day and didnt know there was an expiration date for threads. I have already put 2000.00 into this thing this year and it has been in the shop for 2 1/2 months this camping season. I was just trying to take in all suggestions and hoped to avoid another high price ticket. Anyway, I do appreciate all advice but following this thread or replying to it is ones own choice. Thanks

Of course there is no expiration date on a thread and I didn't mean to come off as an a$$ Sorry.

A Scangauge will tell you things that a service tech will never see because you ECM does not record those parameters as they occur. Unless he is riding along with you with his scan tool plugged in when the problem occurs he isnt going to be able to tell you what the coolant temp was when your issue exposed itself. He won't be able to tell you if you were in open or closed loop. He won't be able to read your fuel trim or Mass Air Flow or see your manifold pressure. He won't be able to see your intake air temp or you O2 readings when the problem occurs. Unless he is riding along with you your service tech will only be able to diagnose a problem that locks in and sets off the CEL.

With a scangauge you can program every single parameter the ECM is monitoring into the gauge. You can monitor the parameters 4 at a time. When the issue comes up you can glance at your scangauge and see if you detect something out of the ordinary. If you weren't monitoring the parameter that caused the trouble you can select 4 different parameters and try to duplicate the problem again.

With a fuel pressure gauge and a Scangauge you will have a lot more information at your fingertips to help you determine the potential issue. So for about $200 or 10% of what you've spent already you will have tools that will help you for the rest of the time that you own the motorhome. No one expects you to be able to look at the scangauge and determine the problem all by yourself. Thats what this forum is for.

On top of your current issue, a scangauge will help you detect lean and rich conditions in the fuel system. These conditions, if not detected early, can cause catastrophic engine damage. I can't put an exact price on an engine replacement in your area but it's a safe bet that it will be in excess of $8000 if you can't do the work yourself. We are driving around in 15 year old coaches with old gaskets and seals and injectors and everything else. If we don't detect problems as they begin it can turn into a big money repair in a hurry.

Again, I apologize for coming off as an A$$.

LETMGROW · 09-12-2017, 07:11 PM

I wish you would go back and read my post #22 once again.
Pulling the codes from your system is only a starting point in an actual diagnosis of your runability issue. They can be helpful but not always conclusive. You said the unit seemed to run better after the codes were cleared. It's possible the code reader operator also reset the system adaptives to factory settings. They will eventually change as the vehicle is driven and the computer runs the diagnostic executives (monitors). This is of course if the code reader had that capability.
A road test trying to duplicate the conditions you are under when the performance problem shows up with a good quality (expensive) scan tool is the only way you will get to the bottom of the issue.
You could and probably should also have a fuel pressure gauge and a vacuum gauge hooked up at the same time.
Not because the scan tool if used to it's full ability can't detect low fuel pressure or vacuum decay but it saves the scan tool operator from changing data screens continuously perhaps missing something else going on.
For example: If the tool operator is watching fuel trims and the scan tool shows the ECM is adding fuel at a rapid rate it could indicate low fuel pressure starving the system of fuel. This can be verified with a drop in fuel pressure on a gauge not feeding the fuel rails properly. Unfortunately no scan tool I am familiar with monitors fuel pressure. The OBD connector doesn't have the capacity to do this.
You have said you have looked for a qualified shop to help you.
Where have you looked? Chevrolet and GMC offered the 8.1 engine in 1 ton trucks from 2001 to 2006.
Workhorse was bought out by Navistar. (International) There are dealers all over the nation. Have you contacted any of these service departments to see if they have anyone who is familiar with this engine?
Most, if not all, the 6.0 engines shared the same engine control systems with the 8.1. Freightliner has built thousands of delivery trucks using the 6.0 engine. I'm sure there are others too.
In my particular case I don't work on trucks larger than 1 ton. I don't have room in my shop to work on them. I don't have the heavy duty software installed in my scan tool to program the large trucks in. It's additional cost. (IE: Workhorse)
What I do is lie to my scan tool and program in a 2002 Chevrolet 3500 series pickup. The tool doesn't know the difference and I can retrieve all the codes and data I want.
There is a big difference between a $49.95 code reader and a professional diagnostic tool approaching $10,000 which has to be updated 2 to 3 times a year at the tune of $750 for each update. Beyond that is hiring qualified techs at a premium price and trying to keep them happy.
The training seminars we continually attend to stay up with the evolving technology isn't free either.
Guessing is only going to cost money and may never solve your problem. You could try to buy every part available for your vehicle but if you missed only one it would be the troubled part anyway. At some time this unit is going to stop running entirely and then you will be faced with having towing costs and being dragged to an off the wall shop which will charge a large price just to say, "I don't know".
I'm not trying to belittle you. I'm just trying to bring you into reality.
Regards,
Lynn

RV Poppy · 09-12-2017, 07:25 PM

Thank you AKIQPilot and understanding that the scan gauge will help me better than the quick scan at the garage will definitely put me in pursuit of one.

As for the big fan on my motor I am attaching a picture and it indeed does run continually with the motor as soon as you start it. Unless there is another I do not see. I had the cover off watching it.

Took her out for 60 miles today and seemed to do well. I did discover that my dual fans in the front work but there is a short in the wiring somewhere. As I jiggled all the wires around them the second started humming. Still have only seen them run with A/C on though.

So for now I will get my fans looked at and look into that scan gauge.

vettenuts · 09-12-2017, 08:00 PM

I think you will see the big fan rotate when the engine is running but it may not actually be "engaged". Does it spin freely by hand with the engine off?

AKIQPilot · 09-12-2017, 08:25 PM

Thanks Lynn for another well written informative post. We all seem to learn a thing or two when you post on the forum.

Like vette said the fan on the front of the motor will always turn when the motor is running. The viscous coupling has just enough friction to make the fan spin although it's spinning slower than the water pump speed. As the engine revs up the fan also speeds up but not at the same rate or RPM. The fans speed is just a component of the viscous coupling friction until the temperature element in the fan allows the fluid in the coupling to engage the hub mechanism and cause the fan to spin at a 1 to 1 ratio with the water pump. Once the temperature element in the fan is satisfied the fluid in the viscous coupling returns to the reservoir and disengages the hub and the fan no longer spins at a 1 to 1 ratio with the waterpump.

A couple quick ways to determine if the fan coupling is bad. 1. With the engine off, if the fan spins freely and will travel more than 1 revolution when you spin it by hand then it very likely has a problem. 2. If the fan does not turn at all by hand and seems to be locked to the water pump shaft then it definitely has a problem. 3. If the coil spring mechanism on the front center of the fan hub is missing then it definitely has a problem.

I've owned several Workhorse chassis motorhomes since 1988. I currently have 2 with 8.1 vortex motors. When the coolant temp reaches about 204f the viscous coupling in the fan engages and you can definitely hear the fan begin to sing. It's not loud but you can hear it. If the coolant temp exceeds about 210f then the viscous coupling is fuly engaged and the fan is roaring. It's not possible to miss the fans sound even with road noise and music. Once the coolant temp is back down to about 198f the viscous coupling disengages and the fan becomes silent again.

Even in Alaska on a 50f day the engine fan will kick on periodically and cool the motor down. If I'm in a steep pull the fan will engage to full roar. It may only last 30-40-60 seconds but there is no question the fan has engaged and is doing it's job.

cfowler55 · 09-12-2017, 08:27 PM

As Lynn has stated throwing parts is usually expensive and frustrating. The only real diagnostic data I see is the DTC's for O2 sensor low voltage. This is an indicator of an extended lean run condition. The ecm/pcm will add fuel til a programmed threshold is reached ( generally in the low 20%range) before turning on the cel. If long term fuel trim is close to there ,even without a cel , I would be looking at fuel delivery and intake air leaks. Goes back to either getting a fuel gauge and monitoring it and scan tool or finding a shop. Friends recommendations and Yelp reviews may point you in the right direction if you opt for a shop. Hope you reach a good conclusion.