At My Witts End

[markortega]

I am reaching out to all you RV Veterans because my RV keeps overheating. I have a 2008 Fleetwood Discovery 39R with only 20k miles. The RV is currently at Freighliner. This is the second time since November it has been there. First they replaced the Engine Harness and the Temp Sensor, this took two weeks to complete. On this visit they have replaced the Thermostat. Monday will be another two weeks they have had it. After speaking with their foreman today, they say it does fine on flat surface but overheats on any grade. Any ideas? I'm at the end of my rope and checkbook?

[islandvagabonds]

Slober tube directs the blowby gases from the crankcase down to the underside of the chassis. On many Freightliners the tube is too short resulting in oil sludge building up on the radiator.
Best solution to this is to extend the tube and hang a small plastic bottle at the end to catch the sludge before it gets blown out all over your toad.

Been there done that with my Discovery

Bob

[TomB_]

Please forgive my ignorance, but WTH is a "slobber tube"? What does it do?

[wolfe10]

I would suggest that if the temperature gauge moves above its normal position except under extreme condition (long, steep grades, particularly with high ambient temperatures) it bears looking into.

Certainly a close inspection of the front of the CAC.

If, indeed it does have a clutched fan, then the "normal" will be a small range-- with thermostatically controlled temperature on the lower end and fan cut in/high speed on the upper end.

[Passin_Thru]

I'd put in a new digital gauge and you never said how hot it got. 230 degrees is not overheating. Above that YUP! My 3406 CAT runs normal T 206-220 and runs 230F up Needles or any other hard pull in hot weather. CAT said run it so I do. Gauges can be notoriously inaccurate.

[2bzy2c]

Thank you for the update. Let us know if your problem is solved.

Good luck!

[mtrumpet]

markortega wrote:
Here is the update. Freightliner said we need to replace the Clutch Fan and Air Dryer. I appreciate everyone responses. I really needed to vent. The engine is a 350 Cummins.

Air Dryer?? I'd like to know what the Air Dryer has to do with the cooling system?? :h

[gatorcq]

Seems, that some people have missed the point about the Freightliner Shop. I would have first called the 24/7 hot line, then from there called Mike Cody, the Freightliner instructor for RV's. Enlist there help and then communicate between the all 3.

It seems the shop is shotgunning which is not uncommon

[BigRabbitMan]

I highly doubt that you have a clutched fan drive as rear engined, rear radiators do NOT have an air flow pattern to activate a clutch. As Wolfe10 says, verify that you HAVE a clutched fan. If not, you know what to do - find a better shop as they let the secret out! Rear radiators must be cleaned, cleaned, cleaned, cleaned. As said above, it would be best if you can do it, but if not have a qualified person do it and MONITOR that they do it properly.

[wolfe10]

markortega wrote:
Here is the update. Freightliner said we need to replace the Clutch Fan and Air Dryer. I appreciate everyone responses. I really needed to vent. The engine is a 350 Cummins.

Fan clutch makes sense (assuming your is not direct drive).

Air dryer service is just routing maintenance and not connected with an overheating condition.

As most have already posted, YOU need to take a strong flashlight and look at the front of the CAC to verify that it is clean. You will be looking inside the fan shroud/between the fan blades. Pay particular attention to the lower perimeter, as that is where debris starts accumulating). While there (access from bedroom or closed) you can verify that you do have a clutched fan, not a direct drive fan.

[jwmII]

After reading all the replies I have to say you are getting some good advice regarding dirty radiator fins (external). This is part of having a rear facing radiator. The Simple Green Extreme is a good start. Not distorting the radiator fins is a must.
Getting in there to get things cleaned up gives new meaning to getting into your work. If you are capable it is better if you do this yourself. If you pay most shops the big bucks to do it you will be going back all the time. It is not a fun job and a lot of people assigned the job are not going to apply the needed effort to do it well. It is also a job you might as well put on your yearly maintenance list of things to do. Be aware there are more than 1 set of fins there. Radiator, charge air cooler, ac condenser and maybe an engine oil cooler. All making the job a bit more involved.

[markortega]

Here is the update. Freightliner said we need to replace the Clutch Fan and Air Dryer. I appreciate everyone responses. I really needed to vent. The engine is a 350 Cummins.

[Helmsey]

Can you let us know what motor you have in it?

[wolfe10]

On a rear radiator DP, I doubt there are electric fans for the cooling package.

Though it is possible it has a clutched fan, the vast majority are direct drive.

As suggested by many, take a flashlight and check the front of the CAC for blockage (from the bedroom).

If Caterpillar engine, check belt tension for the separate V belt that runs the water pump.

[artillery6]

Have the tech check the computer software that governs the temperature where your electric fan kicks in to cool your engine. Mine was not set correctly and the fan did not come on at the right temp. The tech reset the correct temp and everything was ok.