Community Forums

timjet · 10-21-2021, 05:14 AM

I suspect the fan on my '06 400 HP ISL is not operating property resulting in increased coolant and tranny temps.
I would previously see coolant temps in the low 180's during the hot summer months in FL with tranny temps in the 150 range. Yesterday in traffic near Atlanta with air temps in the low 80's I was getting 195 coolant temps and tranny temps at 204. This is a big increase.

So where do I start to diagnose a fan issue or am I going down the wrong rabbit hole?

dwkerch · 10-21-2021, 07:45 AM

You state that temps in FL were lower, but you don't say if temps in FL were lower while in traffic, but that temps in Atlanta were higher "in traffic". Driving in traffic, with numerous starts and stops, will raise both engine and tranny temps.

timjet · 10-21-2021, 08:16 AM

My concern is that this a new issue. I've had this coach for almost 5 years driving in varying conditions including hot FL summers in stop and go traffic and until recently I never saw coolant temps above 185, never.
Now that has changed with both coolant and tranny temps much higher. I know that the engine and tranny temps are still within operating parameters but this is not normal for this engine and tranny.

I called Spartan and to test the hydraulic fan the tech suggested I start the cold engine and note the fan speed. Then stop the engine and pull the fan electrical connection, there is only one, start the engine and note the fan speed with the electrical plug disconnected. I did and though the fan speed did increase it did not go to the speed I would have expected. The tech said it's like a hurricane with the fan speed at high, but as I said that is not what I got.

So wondering where to go now. I guess I need to verify that the fan speed is not going to high. Not sure how to do that. It just doesn't seem to be moving the air that I would expect.

RVThere · 10-21-2021, 08:49 AM

Do you have a rear radiator?

If so, it is a magnet for road debris. On my 2007 Tour, I tried to clean it, spray it with air and water, etc.

I finally had to have it replaced at about 90,000 miles. The mechanic said it looked like a blackboard.

While it was off, I had them replace every pulley, hoses, etc. that were easy to access with the radiator off.

Big bill, but it runs cool for the last 30,000 miles!

timjet · 10-21-2021, 08:51 AM

I have a side radiator and it is clean.

wolfe10 · 10-21-2021, 08:55 AM

Wouldn't hurt to do some normal "routine maintenance" on the hydraulic system.

Change filters and fluid. At the least, it is good PM. At the most, restricted fluid flow can slow fan speed.

Do you have a spin on filter or the large black canister with stacked filters?

Ljwt330 · 10-21-2021, 08:57 AM

Couple of thoughts.

You may have a wax valve in the cooling circuit as well as the electrical connection the mechanic asked you to disconnect. If so, both work together to regulate fan speed with the wax valve needing to be heated by coolant to fully function. Possibly you did not get maximum speed from the fan because the coolant wasn't hot enough. I would try it again after driving and getting the engine up to temp.

timjet · 10-21-2021, 08:59 AM

Side radiator with hydraulic motor that spins the fan. Both the internal hyd filter and external filter and fluid were changed in May and it has 3000 miles on these new filters and fluid.

In talking to Spartan the tech said that indeed restricted fluid flow to the fan motor may prevent it from spinning at high speed but since I have normal steering the tech didn't feel a fluid restriction is the problem.

wolfe10 · 10-21-2021, 09:03 AM

Quote:

Originally Posted by timjet

Side radiator with hydraulic motor that spins the fan. Both the internal hyd filter and external filter and fluid were changed in May and it has 3000 miles on these new filters and fluid.

Glad you have eliminated on of the easy ones.

BTW, your new hotter temperatures are still not out of line.

Contact Cummins with your engine serial number and ask for proper operating temperature.

Another "easy" one is replace the thermostat.

And, are you sure this is not a gauge issue-- could the gauge just be reading high or has it been confirmed by alternate source such as Scan Gauge D, Silverleaf, etc?

timjet · 10-21-2021, 09:07 AM

Quote:

Originally Posted by Ljwt330

Couple of thoughts.

You may have a wax valve in the cooling circuit as well as the electrical connection the mechanic asked you to disconnect. If so, both work together to regulate fan speed with the wax valve needing to be heated by coolant to fully open. Possibly you did not get maximum speed from the fan because the coolant wasn't hot enough. I would try it again after driving and getting the engine up to temp.

The Spartan tech said the fan should go to high speed with the electrical connection to the fan motor disconnected. I asked him again that even if the engine is cold and with that electrical connection removed the fan would go to high speed, his answer is that is the only control and it will go to high speed regardless of engine temp.

It's my understanding after talking to him that the fan has 2 speeds. The engine ECM determines what the fan speed should be based on inputs from the thermostat and possibly from other inputs. If the ECM determines the fan speed should be high it sends no voltage to the fan solenoid thus forcing the fan to high speed. If fan speed needs to be low the ECM sends 12 volts to the solenoid and it reduces fan speed.

timjet · 10-21-2021, 09:19 AM

Quote:

Originally Posted by wolfe10

Glad you have eliminated on of the easy ones.

BTW, your new hotter temperatures are still not out of line.

Contact Cummins with your engine serial number and ask for proper operating temperature.

Another "easy" one is replace the thermostat.

And, are you sure this is not a gauge issue-- could the gauge just be reading high or has it been confirmed by alternate source such as Scan Gauge D, Silverleaf, etc?

Everyone is telling me the engine temp is within normal parameters. The OEM gauges read normal and I am not getting a tranny idiot light. The temps I'm using are from a silver leaf system I installed and I'm reading the temps from my computer.

BUT the temps are higher than they have ever been. I verified tranny temps with an IR gun when I was chasing this problem back in May. AND I'm pretty sure but am not positive yet that the fan is not going to high speed. As I mentioned above, when I pull the fan control plug the fan speed increased but not to the speed I would expect.

There is only one electrical connection to the fan so the Spartan tech is correct when he said that. Since I see no other electrical connection, I would expect he is right that when pulling that plug the fan should go to high. That would be consistent with the temps I'm reading if the fan is indeed not going to high. I don't think the fan is going to high when the plug is pulled, but the fan speed is increasing.

Ljwt330 · 10-21-2021, 09:42 AM

Quote:

Originally Posted by timjet

Everyone is telling me the engine temp is within normal parameters. The OEM gauges read normal and I am not getting a tranny idiot light. The temps I'm using are from a silver leaf system I installed and I'm reading the temps from my computer.

BUT the temps are higher than they have ever been. I verified tranny temps with an IR gun when I was chasing this problem back in May. AND I'm pretty sure but am not positive yet that the fan is not going to high speed. As I mentioned above, when I pull the fan control plug the fan speed increased but not to the speed I would expect.

There is only one electrical connection to the fan so the Spartan tech is correct when he said that. Since I see no other electrical connection, I would expect he is right that when pulling that plug the fan should go to high. That would be consistent with the temps I'm reading if the fan is indeed not going to high. I don't think the fan is going to high when the plug is pulled, but the fan speed is increasing.

First, as an aside, let me say that your rapid and detailed feedback is greatly appreciated. Every area of concern has been responded to, directly, and things are moving forward quickly.

The fan speed seems to be the issue, but you cannot know for certain without a way to measure and compare the rpm of the fan with the specs. Since your chassis has an electrical controller only, then yes, it should default to the highest rpm if the electrical power is removed. I would suggest you get a way to measure the rpm of your fan with the wire disconnected and compare that with Spartan information. It may just be a perception issue.

timjet · 10-21-2021, 10:05 AM

Quote:

Originally Posted by Ljwt330

Snip
I would suggest you get a way to measure the rpm of your fan with the wire disconnected and compare that with Spartan information. It may just be a perception issue.

Yes I agree I need to determine fan speed. I'm not sure how to do that but will figure out a way. I just seem to remember in the past that when the fan speed is high there was no doubt. Today when I unplugged the fan connection while the engine was running I had to listen carefully to determine an increase in fan speed. Yes it increased but not much.

Ljwt330 · 10-21-2021, 10:16 AM

Quote:

Originally Posted by timjet

Yes I agree I need to determine fan speed. I'm not sure how to do that but will figure out a way. I just seem to remember in the past that when the fan speed is high there was no doubt. Today when I unplugged the fan connection while the engine was running I had to listen carefully to determine an increase in fan speed. Yes it increased but not much.

I think this observation alone suggests the rpm is not up to spec. Fans that are running full speed with the coach at rest are easily recognized by the sound and the force of the air coming from under the coach. There is no way one would miss a fan at high speed. If you had to listen carefully, something is amiss.

I am not familiar with the hydraulic circuit on fans that only have electric controllers so I am going to sit back and simply follow along. Logic says, however, that the valve controlled by the solenoid must be failing to fully close, preventing the fan from going to full speed. Since that valve solenoid is controlled by the ECM, regardless of the message sent by the computer, the valve itself is failing to respond correctly and the fan never reaches full rpm when called upon.

Certainly, Spartan will know if it's possible for the valve to get stuck or otherwise fail to allow complete function of the fan.