Community Forums

Ranger Smith · 02-17-2016, 04:22 AM

The only thing left is the fan controller and sensor. I would call Freightliner and and ask them for info on how to test the unit and explain the problem to them. Also was fan replaced maybe by someone other than you and are blades on correctly?? Air is not getting through that radiator sufficiently to cool that water. Are you sure there is a 50/50 mix in the cooling system?? Has the system been bleed for air?? An air pocket in the cooling system would cause this also. Even our little diesel motor in the generator will overheat if not bleed properly.

If it were mine . . . Radiator out and tested at radiator shop. Fresh antifreeze . . . Fan controller and sensor tested.

koda59 · 02-17-2016, 08:23 PM

On my Mandalay the controller is located on the back side of the radiator. If you lay down under and look at the fan the controller is on the back side. It is a 3X3 box with many wires. If I remember correctly there is one single black wire. This is the ground. Disconnect this wire and the fan should default to high fan speed.

Hitchin · 02-18-2016, 12:02 AM

Will check with Freightliner again but when I spoke to tech services some time ago and explained my problem no reference was made to the fan controller and sensor. I will post when I have spoken to them

Rich-n-Linda · 02-20-2016, 07:02 PM

I've been down this road in our 2006 Mandalay 40E.

The problem is that your cooling system is not providing enough cooling power. The fan control system consists of a temperature sensor, the fan controller, the hydraulic pump and the hydraulic motor on the fan. Failure of the pump and motor are very rare. Failures of the temp sensor and fan controller are very common. Testing the system by running the usual static tests with the computer did not show anything wrong on our coach, as your tests have shown. I don't think the "testing" procedure gives you a clear picture of the health of the system.

I faced overheating issues on grades, just as you are. Shifting down and keeping the revs up did not help. And, as you said, at 225 degrees the dash starts to look like a pinball machine.

Freightliner Factory Service in Gaffney, SC just replaced my fan controller. The temp sensor had already been replaced. My engine now runs at 200 degrees. On the big grades on I-26 (45 - 50 mph in 4th gear, wide open throttle for several miles) the temp rose to 205. Within 30 seconds of cresting the grade and getting out of the throttle, the temp was back to 200.

If it is at all possible, make an appointment with the Freightliner folks in Gaffney. They KNOW the system and will be able to fix it.

Rich-n-Linda · 02-20-2016, 09:20 PM

One more thing...the wiring and interconnect diagrams you asked about are available from Freightliner. Get set up with an Access Freightliner account and you can get everything you need on that chassis.

koda59 · 02-21-2016, 09:24 PM

A few years ago, I was attending the freightliner class and Mike started talking about the hydraulic fluid used in the steering and the cooling fan. I raised my hand ( back in school days lol) and I told him my system had 15w40 motor oil. He told me that is incorrect. He then said that there is a tag on the tank telling you to use hydraulic fluid. I told him that had been painted over with black paint and a new sticker said to use the engine oil. After our break for lunch Mike told the class I was right. For some reason certain rvs had to be switched because the hydraulic fluid could not handle the temperatures. When you talk to freightliner support you might ask them the number.

Rich-n-Linda · 02-29-2016, 09:39 PM

Hitchin' have you been able to solve this problem?

Hitchin · 03-06-2016, 09:55 AM

I spoke to Freighliner in Gafney and they want me to get a check done on the fan speed before I start changing parts. They gave me the name of a service Centre in Chino CA but on checking the comments on this shop I was unhappy with the remarks on service and attitude so I am going to check with a recommended Centre in Temicula CA. I have spoken to Freightliner in my home town but they are suggesting just changing parts without further action on fan speed. I noticed on another forum that several Mandalay owners had the same trouble one of whom published a test using a multimeter to check the resistances across the six pin plug to the fan controller this I will try myself BUT all correspondence points to the controller. The saga continues!

Hitchin · 03-08-2016, 11:11 PM

Quote:

Originally Posted by Rich-n-Linda

Hitchin' have you been able to solve this problem?

No the problem still exists, still working on it

Hitchin · 04-20-2016, 11:48 AM

Currently at Freighliner Las Vegas hoping for a solution to my problem but they seem to be all over the map with this problem. Will have some answers later today I hope!

Chuck48 · 04-20-2016, 04:03 PM

Good

Chuck48 · 04-20-2016, 04:05 PM

Sorry, that was a text to my wife that went haywire. Don't you hate it when you get old.

koda59 · 04-23-2016, 05:33 PM

Have they disconnected the ground wire to ensure that the fan defaults to high speed? I think this is the first thing I would do. My fan stayed on high all the time, so My temps were always low. My temps now run 197 to 199. That is according to my scan gauge d.

Rich-n-Linda · 04-24-2016, 03:11 PM

I just remembered something else which caused another overheat situation in our coach.

The clamp on the exhaust side of the turbocharger had failed. Some of the exhaust gasses were leaking past that joint. Those hot exhaust gasses blowing around back there disturbed the air flow from the fan, which is right next door, so speak. When that clamp was fixed, the overheating stopped. An induction leak in the hose between the CAC and the engine will cause the same symptoms. (Ask me how I know!!)

Make sure the techs check the entire induction and exhaust system for leaks. A leak on either side (intake or exhaust) will disturb the air flow from the fan, lowering the capacity of the system to cool the engine.

Good luck with your repair.