Originally Posted by DIGGERS CREW
In april of this year we purchased our first motorhome,a 36' 2006 Winnebago Journey with a Cat C7 350hp Diesel engine and a Frieghtliner chassis,from a RV dealership in Iowa. We live in west central Illinois and over the first several months we took several trips close to home to get the hang of things. We purchased a car tow dolly also. In July we took a trip to Omaha and things went great. We then decided to take a trip to the east coast the first week in August. Not knowing for sure about the maintenance schedule of the coach I made an appointment with the RV dealership to have it serviced. We take off on the trip and stop the first day right before we have to drive through the mountains. On the second day we are going up a mountain grade and the coach starts to over heat(threshold 216 degrees) so I pull over and let it cool down and then we're able to finish to the top. The temperature gauge rose several more times during the drive through the mountains. Once we arrived at our destination I went to unhook my toad and found it covered in oil along with the tow dolly.Worried that something bad had happened I made several calls and found some info on the net on what might be the problem. When we returned home I checked my maintenance record and the RV dealership had put 26 qts of oil in the engine plus the filter. From my research on IRV2 this was to much. I will be calling Freightliner on Monday to check oil capacity. I'm also wondering if the engine being overfilled would have caused the engine over heating issue? Because now just driving on normal roads the engine temperature will fluctuate from 197 to 212 degrees. Any thoughts on my problem would great.
Well Sir, first off, YESSSSSSSS that is tooooooo much oil. About 99.999999% of the C-7 engines out there use 19 quarts. But, this is based on what size oil pan you have. And, like I stated, about 99.9% of them have what's called the "small" oil pan. With all that being said, during an oil change, all the oil is drained and, even with a two-quart filter, you put a grand total of 19 quarts in it, PERIOD! But do make sure which pan you have.
Now, you also have what's called a "blow-by" tube. That's a tube that comes off the top of the engine and, vents all internal pressures built up during engine running processes. And, it's been determined by Freightliner and others that, most of those blow-by tubes, exhausted the blow-by gasses at a mid point of the length of the engine. When that happens, any oil mist fumes, get sucked up by the volume of air movement created by the direct drive engine fan.
And, since that fan is BLOWING on the CAC and radiator to keep things cool, it's also blowing that oil mist onto the fins of those two units. So, when that happens, it's (the fan) also picking up dirt, debris, dust, cigarette butts, and more, and depositing it right into and onto, those oil soaked fins.
When that happens, pretty soon (or, over a length of time and mileage) you have NO AIR being able to go through the fins, to help cool the coolant down because of blocked fins. This, most of the time, doesn't present a problem while cruising down the flat road. But, enter a grade and, present some nice warm outside temps and, you now have a rising temp in the engine due to no or, less air flowing through the fins.
This is a common occurrence with many, many diesel pushers with rear radiators. Now, here's some solutions.
1. Due make sure that, you only have 19 quarts in that engine, based on your oil pan size. If more than 19, that engines operations picks up the extra oil and slings it about and, some of it get's thrown into the blow by tube. So, make sure you have the correct amount.
2. Make sure that blow-by tube, has been extended to the rear of the coach. That will ensure that, ANY fumes and oil mist which, should be a minimum or, none, if the engine has the right amount of oil in it are dispursed beyond the fins of the radiator and the CAC.
3. Check those fins out carefully. Get an inspection camera or, take the bed apart or, do what ever it takes, get a close look at those CAC and radiator fins, from the FAN SIDE and see if they are clogged and dirty.
4. If they are, this can be a pain and costly. There's many answers to this issue. A. Do what it takes to get them clean
B. Pay the RV service center to do it.
C. Some cut an "Access Panel" in the top of the radiator shroud to access the CAC and radiator from inside the coach, and clean it that way.
5. Make sure your coolant is up to the correct level and, your engine fan is in good condition. Some have had the blades disintegrate due to age and heat and, didn't know it.
6. Make sure your fan belt (serpentine) is in good shape and tight. It has a spring loaded tensioner to keep it at the correct tension but, it doesn't hurt to get in there and check for sure.
Well l hope I've given you some info to get started with. Good luck.
P.S. One more thing. When ascending grades, and, your engine starts to climb in temp, make sure you down shift at the correct speed etc. to keep that engine running at a bit higher RPM which, ensures the fan is pushing max amount of air through those two units and, you're not lugging it. The trans will, at a pre-determined time and speed, downshift on its own but, sometimes, that's a bit late and, the temp has already started to rise. So, to head off the heat or, at least make an attempt at it, judge when it's time to down shift so you can help avert the higher operating temps. Good luck.