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wsmcycle · 10-17-2017, 06:49 PM

cat 3136b. How does your engine respond at 2200 rpm. perhaps you have never hit it. my problem can occur at 1500.... Anywhere that you can hit high enough power to starve the fuel flow

wsmcycle · 10-17-2017, 06:52 PM

oops 3126b

jpsageusa · 11-19-2017, 09:56 PM

We just came south over the grapevine in SoCal and my 2500 hunted. This our first long outing with a toad. My lsb 5.9 300hp likes to climb at 40 mph in 3rd gear. I used the arrow key to select 3 and it stayed in 4th. I was monitoring the temp on my Silverleaf and it climbed towards 220. Years of traveling in a Ford 6.9 4-speed taught me the techniques you guys have been talking about here. But the computer seems to be the boss.

On the next hill I will try getting off the throttle earlier and getting into 3rd and see if it stays. Am I missing something?

Thanks for any incites.

Oh my toad, a Chevy Spark, is less than 2400 lbs.

Bigd9 · 11-20-2017, 06:52 AM

The way it is supposed to work, if you select 3rd gear, and the computer agrees that the engine will not go over the maximum RPM, then it should shift to that gear.

If the computer says "if I go to 3rd gear the engine will go over the maximum RPM", then it won't down shift and it will go to the lowest safe gear even though you may have selected a lower gear.

My own feelings are, I let the engine/transmission computer do all the shifting for me, and I never touch the transmission panel. I just put her in "D" and never give it another thought. She shifts ups, she shifts down all on her own matching the power needed with the proper gear to get the performance expected. If the transmission is hunting on that rare perfect grade where the computer can't make up its mind, I may hold the transmission in the lower gear until the road grade either steepens or flattens out.

Problem #2
Now, if you are seeing engine temperatures approaching 220 degrees, you have a serious problem other than what engine RPM you are running. If I were you, I would check the TWO radiators (CAC and Engine Coolant) for dirt and external clogging. Your coach has a engine breather tube (slobber tube) that will dump fumes into the air just before the two radiators. These fumes will attract dirt that will externally clog the radiators. If you overfill the engine with oil, the matter is a lot worse because excess oil will be pushed out the slobber tube and coat the radiators attracting dirt.

Have you even cleaned the radiators? I clean mine once a year using a aluminum safe form of Simple Green and plenty of water. I have a set procedure I use if interested.

jpsageusa · 11-20-2017, 07:36 AM

Yes I would like your procedures. Either here or pm. I am always ready to learn as well as doing my own work.

Bigd9 · 11-21-2017, 06:00 PM

Quote:

Originally Posted by jpsageusa

Yes I would like your procedures. Either here or pm. I am always ready to learn as well as doing my own work.

The topic of cleaning the radiators comes up often on this and other forums. I'm going to post my method here just in case others have missed it need the information. I invite anyone to add comments or make corrections to my narrative as you feel is needed.

Cleaning the Radiators

Here is how I do it with my rear mounted radiator/CAC. I start the engine and warm the engine coolant. My opinion is anything that gets oily seems to get cleaned better if it is warm.

First and most important, make sure all vehicles, like your wife's brand new SUV are nowhere near the rear of the coach.

From the inside of the coach, I remove the floor to gain access to the engine side of the radiator. In my coach, that radiator you see with the floor removed is the charged or compressed air cooler.

I use a garden sprayer and mix a 50/50% of Simple Green HD or Extreme and warm water.

I spray the solution on and all around the CAC. Then I start the engine and let the spinning fan blades driving the solution through the radiators. Normally I spray some more while the engine is running being very careful of the spinning blades. You should see Simple Green bubbles exiting the radiator from the outside as the fan pushes the solution through. Shut the engine down and go get a cold or hot drink of your choice.

After I finish my drink, start the engine, and from the inside of the coach I spray an abundance of water all around the CAC letting the engine push the water all the way through. If you have access to hot water to use all the better. After a few minutes of spraying water I shut the engine down and drag the hose to the rear outside of the radiator and spray from the rear of the coach forcing water through the radiator toward the engine making sure I cover 100% of the exposed radiator area.

The first time I did this I had a large "under the bed plastic storage container" located under the radiators and I was shocked at the amount of sludge that came out and accumulated inside the box!

Repeat the process as many times as needed to get the entire area clean. It might take 3 or more times for stubborn cases. Some owners use a air measuring device to see what the airflow is coming out of all parts of the radiator. This will pin point any really clogged spots.

Notes:

There are many variations other use to my method. This is not the definitive or only way. It just is my way, and the way that makes the most sense to me.

It is important to extend the slobber or blow-by tube so it exits below the radiators, or even better so it exits to the rear of the radiators. This will keep the fan from sucking the fumes or actual oil droplets and blowing them right through the radiators making them a sticky mess. Once that blow-by tube is tactically placed, you should have little oily gunk accumulating on the radiator in the future.

Since you have the floor removed, now is an excellent time to change the secondary fuel filter, and to lubricate the Pacbrake according to the manufacturer instructions, if you engine/coach has one.

CountryB · 11-23-2017, 04:49 AM

Quote:

Originally Posted by Bigd9

I spray the solution on and all around the CAC. Then I start the engine and let the spinning fan blades driving the solution through the radiators. Normally I spray some more while the engine is running being very careful of the spinning blades. You should see Simple Green bubbles exiting the radiator from the outside as the fan pushes the solution through.

Doesn't the fan "pull" air through the radiator?

On my PU one way to test the fan clutch is working is to put a piece of paper on the outside of radiator/grill and see if the paper is sucked (held) against the radiator by the fan pulling air in.

Of course on my pickup the radiator in the front - so maybe the air flow is reversed when the radiator is in the rear.

Learn something new every day.

Bigd9 · 11-23-2017, 05:24 AM

Quote:

Originally Posted by CountryB

Doesn't the fan "pull" air through the radiator?

On my PU one way to test the fan clutch is working is to put a piece of paper on the outside of radiator/grill and see if the paper is sucked (held) against the radiator by the fan pulling air in.

Of course on my pickup the radiator in the front - so maybe the air flow is reversed when the radiator is in the rear.

Learn something new every day.

Thanks for the question and you are absolutely correct on your pickup. It does pull the air through. BUT, in diesel pusher motorhomes, the engine and transmission are actually mounted "backwards" from the way the automobile or pickup trucks are. Because of this, the fan....and it is a BIG fan.... actually pushes the air through the two radiators. This picture came from the internet.

jpsageusa · 11-23-2017, 10:58 PM

I will definitely clean the radiator(s) as soon as I get somewhere to do it.

But...

If the crud is coming into the radiator from the engine side, wouldn't you apply the cleaner and then spray water from the other side? That would allow the crud to be pushed out the way it came instead of pushing it the rest of the way through the radiator(s).

And...

It really grips me that the first thing I did was to take the motorhome into a service center and asked for a complete inspection/service. Now a year later I realize that they just changed the oil and lubed the chassis. A long time ago I learned that I couldn't trust automobile service centers with my cars. Now I had to learn the same lesson with a DP and they are a lot more complex. As the wise man said, "Would you like some cheese with that wine?"

I hope that everyone had a great Thanksgiving. And 90 degrees in SoCal was much better than 56 in NW Washington.

Thanks, John.

Bigd9 · 11-24-2017, 06:45 AM

Quote:

Originally Posted by jpsageusa

I will definitely clean the radiator(s) as soon as I get somewhere to do it.

But...

If the crud is coming into the radiator from the engine side, wouldn't you apply the cleaner and then spray water from the other side? That would allow the crud to be pushed out the way it came instead of pushing it the rest of the way through the radiator(s).

And...

It really grips me that the first thing I did was to take the motorhome into a service center and asked for a complete inspection/service. Now a year later I realize that they just changed the oil and lubed the chassis. A long time ago I learned that I couldn't trust automobile service centers with my cars. Now I had to learn the same lesson with a DP and they are a lot more complex. As the wise man said, "Would you like some cheese with that wine?"

I hope that everyone had a great Thanksgiving. And 90 degrees in SoCal was much better than 56 in NW Washington.

Thanks, John.

Excellent question John! All I can say is what my Appalachian Hillbilly thinking is telling me. You are correct about the way the dirt gets in the radiators, and there is nothing terribly wrong with spraying the cleaner and water from the other side.

But remember, there are TWO radiators stacked with one in front of the other separated by about 1 or 2 inches of space. By trying to spray from the outside it will be difficult to get the cleaner through the outside radiator, pass that space and into the inner radiator. The method I described uses the diesel engine to push the cleaner and water through both of them. You can see if it is working by looking at the outside radiator when the engine is running as see the cleaner bubbles foaming all over the radiator. You should see the bubbles uniformly all over the surface. Here is a picture of what one owners radiator looked like after he removed the radiators for cleaning. The dirt was really stuck between the two cores.

If you just bought your coach used, do you know ...

age of your tires?
age of your batteries?
has the antifreeze been changed?
has the compressed air dryer filter been changed? This is very important!
air filter been changed within the last 3 years?
are the fuel filters the correct ones? You have either one or two fuel filters. Diesels demand clean fuel and the incorrect filter could allow unacceptable particles to pass.
from underneath the coach, can you see the brake shoes, and do you see any fluid leaking down from the brake shoes and onto the tires? (bad axle seal)