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Topic: 2004 U320 ISM doesn't warm up (Read 3294 times) previous topic - next topic

2004 U320 ISM doesn't warm up

I'm having some issues with my 2004. I took it out last weekend and went to New Symrna Beach in Florida. Temperature was 20°F ish when we left Atlanta and didn't warm up much till we were well into Florida. The coolant temperature never got warm. I was cruising on the interstate at 75 mph, with a toad and the engine temp was barely 100°F. I also had very little heat from the dash. The transmission temperature was also very cold. The gauges, and two digital displays all matched temperatures. On the way back, I had ~175°F coolant temperature for half the trip, then it dropped for the second half.
So I figured the thermostat was stuck and I'd replace it when I got home.
I just replaced it today and it's still having the same issue. The original thermostat was not stuck, I checked it with some hot water and it worked fine. I did a stall test and held the engine at full power against the brakes and the engine warmed up very slowly then cooled back down.
The radiator hose coming out of the thermostat housing is warm, and I wasn't expecting that to have coolant flowing until it warmed up.
Does anyone have a diagram of how this is plumbed up? Or any suggestions? Is there another valve somewhere that should be closing? Thanks.

Re: 2004 U320 ISM doesn't warm up

Reply #1 –
If you have an IR gun, use it to check temperature at the thermostat housing.

That will help you determine if this is a temperature or gauge issue.

Re: 2004 U320 ISM doesn't warm up

Reply #2 –
They match.

Quote from: wolfe10 –
If you have an IR gun, use it to check temperature at the thermostat housing.

That will help you determine if this is a temperature or gauge issue.

Re: 2004 U320 ISM doesn't warm up

Reply #3 –
So curious. Are the radiator fans running hiwhen cold. If you disconnect the plug on the controller they should ramp up to max speed cold

Hydraulic fan controller DIY

Re: 2004 U320 ISM doesn't warm up

Reply #5 –
While I completely agree that running the fan on high is not desirable from a HP, MPG, noise and dust standpoint, unless the thermostat (or alternate plumbing) sends coolant to the radiator, the amount of air passing through the radiator should not be a big factor in coolant temperature in the engine.

Re: 2004 U320 ISM doesn't warm up

Reply #6 –
4k
Quote from: wolfe10 –
While I completely agree that running the fan on high is not desirable from a HP, MPG, noise and dust standpoint, unless the thermostat (or alternate plumbing) sends coolant to the radiator, the amount of air passing through the radiator should not be a big factor in coolant temperature in the engine.

That was my thought too. Sensors measured 4k ohm at 45°F, which is about right according to the chart,

Re: 2004 U320 ISM doesn't warm up

Reply #7 –
Yes, another way to look at cooling through the radiator:

Engine temperature should be the same with fan on high or low (unless under high load when it may rise somewhat).

Engine temperature should be the same if 20 degrees F or 100 degrees F (unless high load when it may rise somewhat).

Fan speed and ambient temperatures should not impact coolant temperature.  Extreme example is Ice Road Truckers who often drove in -20 degrees F.  Their engine temperatures were as they should be.

Re: 2004 U320 ISM doesn't warm up

Reply #8 –
Look for other sources of heat loss from the engine. Start with the interior heating system and the hydronic heating system. Be sure that there is not flow from the heating loop into the water tank. A pump running that shouldn't or one of the systems check valves.
Is there a combination of engine coolant and the external oil cooler for the transmission? I'm still trying to figure this out on mine. I am finding it amazing that the transmission always gets close to engine temperature even at low speeds and low outside temps. There is likely a thermostat or other flow control for the external cooler. 
I will suggest that this is a priority to get resolved. Operating the engine in this manner can be damaging. There is often mention of wanting service records and stuff for the value of a used coach or a purchase decision. Events like this often happen and quickly make how often the oil was changed meaningless. Rare is the engine or transmission that has not suffered a trauma. 

Re: 2004 U320 ISM doesn't warm up

Reply #9 –
Fan controller is bad. It turns off the fan for about 10 seconds if you unplug it and plug it back in, but then the driver starts to fail and the fan turns back on. I tested it on my bench.  It worked once for a bit, then went back to failing.  With the fan not running it does warm up, but drops as soon as I turned the fan on. I'll put a different controller on, I have multiple on my bench from my job.

Where is the coolant sensor on this engine? I can't seem to find it.

Re: 2004 U320 ISM doesn't warm up

Reply #10 –
The fan may also be turned on for some speed with the AC compressor. AC should also be called for with defrost. 

Re: 2004 U320 ISM doesn't warm up

Reply #11 –
Quote from: Dennis H –
The fan may also be turned on for some speed with the AC compressor. AC should also be called for with defrost.

The A/C condenser is on the other side and has it's own fan. The controller is monitoring coolant and intake temperature.

Re: 2004 U320 ISM doesn't warm up

Reply #12 –
Quote from: kgrover –
The A/C condenser is on the other side and has it's own fan. The controller is monitoring coolant and intake temperature.

Forgot about the AC condenser being separate. My 08 has it in front of the charger air cooler alongside the transmission cooler.

Re: 2004 U320 ISM doesn't warm up

Reply #13 –
Quote from: wolfe10 –
Yes, another way to look at cooling through the radiator:

Engine temperature should be the same with fan on high or low (unless under high load when it may rise somewhat).

Engine temperature should be the same if 20 degrees F or 100 degrees F (unless high load when it may rise somewhat).

Fan speed and ambient temperatures should not impact coolant temperature.  Extreme example is Ice Road Truckers who often drove in -20 degrees F.  Their engine temperatures were as they should be.
So why do they cover the radiator?

Re: 2004 U320 ISM doesn't warm up

Reply #14 –
Quote from: dsd –
So why do they cover the radiator?

Even with no fan -20 degrees F over the engine (front engine/front radiator, so at 50 MPH> 50 MPH wind through the engine room) can over-cool it even with no or little cooling in the radiator.

Re: 2004 U320 ISM doesn't warm up

Reply #15 –
As Kgrover has found through his own diagnoses those fans are able to shed allot of heat away from the engine. You can take a look at the wax valve conversion a few of us on here have done. I have set mine up so that I can run either one. Jim.

Re: 2004 U320 ISM doesn't warm up

Reply #16 –
I setup a new fan controller to replace the Sauer-Danfoss FDCA controller that failed. The fans are working great now. I set the fan on/off temperatures to the chart in The selected media item is not currently available., page 483.

The first chart is where I was loading the engine up by holding the brakes with it in gear to get some heat into it. The green line is the temperature from the engine ECM, the blue line is from the fan controller. The sensor for the fan controller is farther back in the side of the block. The engine ECM reads the temperature at the thermostat housing. 100% fan, means the command is 100% and the fan is off since the solenoid is normally open, it needs current to close and stop the fan.

Second chart is at high idle with the A/C running to get a little more load on the engine. You can see the temperature climb and the fan ramp up and down to match it. It looks like it's working pretty well.

Last picture is the controller installed where the original one was. I need to work on the mounting bracket a little more, but it worked for testing.

This with the new thermostat should fix my over cooling issue.

There is also a TSB from Cummins on the over cooling issue where the thermostats can stick open.
QuickServe Online

Re: 2004 U320 ISM doesn't warm up

Reply #17 –
Awesome write up  ^.^d

I've attached the TSB from the above link

Re: 2004 U320 ISM doesn't warm up

Reply #18 –
Did you go to something different to the Sauer-Danfoss?

Quote from: kgrover –
I setup a new fan controller to replace the Sauer-Danfoss FDCA controller that failed. The fans are working great now. I set the fan on/off temperatures to the chart in The selected media item is not currently available., page 483.

The first chart is where I was loading the engine up by holding the brakes with it in gear to get some heat into it. The green line is the temperature from the engine ECM, the blue line is from the fan controller. The sensor for the fan controller is farther back in the side of the block. The engine ECM reads the temperature at the thermostat housing. 100% fan, means the command is 100% and the fan is off since the solenoid is normally open, it needs current to close and stop the fan.

Second chart is at high idle with the A/C running to get a little more load on the engine. You can see the temperature climb and the fan ramp up and down to match it. It looks like it's working pretty well.

Last picture is the controller installed where the original one was. I need to work on the mounting bracket a little more, but it worked for testing.

This with the new thermostat should fix my over cooling issue.

There is also a TSB from Cummins on the over cooling issue where the thermostats can stick open.
QuickServe Online

Re: 2004 U320 ISM doesn't warm up

Reply #19 –
Parker IQAN MC41

I used an IQAN MC41 controller mainly because I have them and the software to program it. I'm the Application engineer for Mobile electronics for Parker-Hannifin for the South East. So I had one on my bench and it's really easy to setup. It's got more I/O than is needed for just a fan controller, but it works great. I used the existing sensors and control valve. I also tied it into the CAN network for the coach so it can send error messages up to the Bluefire display if anything goes wrong.