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Fan test & question

Yahoo Message Number: 62931
With a digital tach I measured the fan speed as follows: Engine on, AC & vents off 972.4 RPM Engine on, AC on 972.4 RPM

Engine in neutral for both, engine cold.
I presume this to be low RPM. What should high RPM read? Should it have gone to high RPM with AC on? Lyle Wetherholt

04 Intrigue 11740, ISL 400

Re: Fan test & question

Reply #2 –
Yahoo Message Number: 62947
Lyle, don't know if this will help you or not, but these are the test spec's for your engine.

Thanks, Mike 03 Allure 1st Ave #30898

Cummins   ISL400-03 ECM Controlled Fan Fan speed   Engine R.P.M.   Range
Min   Idle      0-500
Med      Idle      800-1300

Med/Engine   2.1K      1300-1800
Fast      Idle      700+

Fast/Engine   2.1K      2.3+

Cummins   External Thermostat Controlled Fan Fan speed   Engine R.P.M.   Range
Min   Idle      0-500
Med      Idle      800-1300
Fast      Idle      2K+

Fast Engine   2.1K      2.6K-3K+

Re: Fan test & question

Reply #3 –
Yahoo Message Number: 62949
Mike

do you have the specs. for a Cummins ISC 325 HP ? Greg

Re: Fan test & question

Reply #4 –
Yahoo Message Number: 62952
Greg, No I don't have those spec's but I believe they are not applicable. I assume you have an ISC 330 which Country Coach used a Thermostatic Wax Fan Controller...as the wax got hotter the fan ran faster and vice versa.
I do not know who made the controller but you could call Specialty Logistics @ 541-515-6651 ask for Tim or call Country Boys RV - Doug Beaudry Owner @ 541-935-0848 or 541-2252169. I do know they often failed and therefore the fan defaults at Full RPM to make sure the engine is cooled, uses more HP and lowers fuel milage.

Thanks, Mike 03 Allure 1st Ave. #30898

Re: Fan test & question

Reply #5 –
Yahoo Message Number: 62961
Quote
Quote from: allure012000"
Mike,

Thanks for the info. I will add it to my coach info file. My issue is that the fan does not go to high speed with the AC on as many have said it should. So, I don't really know if it ever goes to high, even with high coolant temps. Further, what is high temp as regards the fan; 190, 200, 220?? Sure will be difficult to tach it at high temp.
Lyle Wetherholt
04 Intrigue 11740
> Lyle, don't know if this will help you or not, but these are the test spec's for your engine.

Thanks, Mike 03 Allure 1st Ave #30898 >

Cummins   ISL400-03 ECM Controlled Fan > Fan speed   Engine R.P.M.   Range
Min   Idle      0-500
Med      Idle      800-1300

Med/Engine   2.1K      1300-1800
Fast      Idle      700+

Fast/Engine   2.1K      2.3+

Cummins   External Thermostat Controlled Fan > Fan speed   Engine R.P.M.   Range
Min   Idle      0-500
Med      Idle      800-1300
Fast      Idle      2K+

Fast Engine   2.1K      2.6K-3K+

Quote from: Lyle"

>

> With a digital tach I measured the fan speed as follows: > > Engine on, AC & vents off 972.4 RPM > > Engine on, AC on 972.4 RPM

> Engine in neutral for both, engine cold.
> I presume this to be low RPM. What should high RPM read? > > Should it have gone to high RPM with AC on? > > Lyle Wetherholt

> 04 Intrigue 11740, ISL 400
>

Re: Fan test & question

Reply #6 –
Yahoo Message Number: 62964
Lyle,

My fan has never gone to high speed when the dash ac is on. Of course that doesn't mean that is isn't supposed to. I believe that I have read in posts in the past where it may have to be on in a certain configuration of the controls but not sure.
My fan will come to full speed at 204 and drops out around 190. Climbing a long grade 6% + it will cycle the temp between those two points and I can clearly hear the fan come up and drop back if I have the driver's window open. It is even more obvious if the coach is in the left lane next to guard rails or Jersey barriers. Sometimes on really hot days it will stay on high all the way up but I can hear it drop back once over the top. The fan makes a lot more noise when being driven at full speed.
I have installed a switch on my dash in series with the fan controller fuse in the bay under the driver's window. That allows me to force the fan to high speed anytime I wish.

Don Seager

2004 Allure 31046
370 Cummins ISL

Quote from: "Lyle"

>

> With a digital tach I

measured the fan speed as follows:

Quote
Engine on, AC & vents off

972.4 RPM

Quote
Engine on, AC on 972.4 RPM
> Engine in neutral

for both, engine cold.

Quote
I presume this to be low RPM. What should

high RPM read?

Quote
Should it have gone to high RPM with AC on?
 > Lyle Wetherholt

> 04 Intrigue 11740, ISL 400
 >

Re: Fan test & question

Reply #7 –
Yahoo Message Number: 62965
Lyle, my suggestiong is to bring your coach to full temp driving without dash A/C on, stop and pull the 2 wire power connector from the Fan Controller which will set the Controller to the Default and should then send your fan to FULL HIGH RPM. Note if there was a change in RPM of fan when you pulled the 2 wire power connector versus when you first stopped to do this.
Regarding with the A/C Dash on, I believe the ambient temperature and Trinary Switch - High Pressure/Low Pressure are a part of determining fan speed.
I know when going down the road at say 83 degrees ambient temp. and A/C on, the engine coolant temp may range around 196 degrees whereas when its 96 degrees ambient my coolant temp with A/C on ranges around 188-191.

Good luck on your search.

Mike 03 Allure 1st Ave. #30898
 

Re: Fan test & question

Reply #9 –
Yahoo Message Number: 62978
Lyle, the A/C being on does not make the fan go to high on my coach or probably on yours. With the A/C on and the trinary switch sensing high head pressure the fan will go to high.
I can tell you quite precisely how the Sauer Danfoss 1090409 controller manages fan speed as related to coolant temperature.
First, assume that the only fan speed control device is the coolant temp.
Also assume that your engine coolant thermostat is operating correctly which means that it starts to open at 185 and is fully open at 195.
With your coolant temp below about 193 the fan will be turning at its' slowest speed.
As the temp rises through 193 the fan speed will begin to ramp up continuously variably.
If the temp continues past about 198 (as it will more often than not) or for more than 30 seconds the speed will have ramped up to full speed.
The temp may rise as high as 202 or 204 depending on the heat causing variables such as speed, ambient temp, grade, throttle position, weight......
Then the temp will drop under high fan to about 191 or 192 where the fan speed will ramp down to low speed.

While the fan speed is ramping down the temp may drop to 188 or so

The cycle begins again.

However, coolant temp is not the only controlling variable. Also is the A/C high side pressure as mentioned and charge air cooler temperature.
As to whether your controller is taking your fan to high speed or not. If you are not over heating while driving in the summer your fan is spending time on high speed.

George in Birmingham
'04 Allure 31038
George in Birmingham
2003 Magna 6298