Radiator question

[jhs1881]

Being a newbie with only one long trip under my wheels, (east coast to west coast and back) this will be my first of MANY questions regarding my MH. I have an '07 Newmar Ventana on a Spartan Chassis, 300 hp Cummins engine. My question is this: is it normal to have to add coolant periodically, or is this something I need to have checked out? The temp seems to go from the 180's to 210-ish before the fan kicks in and then drops right down. The only time my overheat alarm went on was when I lost a belt that drove the coolant pump, so I'm pretty sure I'm not over heating.
Thanks

[Martind4]

Our rig doesn't require adding coolant periodically. I can check the level visually thru the expansion tank. Ours is a rear radiator and it gets cleaned once a year to maintain good airflow.

[jhs1881]

That could be my issue....I don't believe I have an expansion tank....If I do, it'd not visable. I have the same rear radiator setup...I can see the rubber hose that runs from the radiator cap along the top of the radiator but it dissapears along the side.

[GaryKD]

Hi jhs1881,
My coach is a rear radiator Cummins ISC 330 HP. Once a year the radiator fins are blown out with high PSI air hose. My definition is about 150 PSI. My engine temp will increase depending on the outside temp and if I am going up hill.

When your temp increased what was the outside temp? Were you going up hill? Were you towing a car or trailer?

I do have an expansion tank. It is located inconveniently on the passenger side at the top of the engine compartment.

[HeapBigEngin]

Your Cummins should have an expansion tank somewhere, and, if it does, it is likely under pressure during normal operation. If the tank cap(s) are loose, you can lose coolant easily there. Has the system been flushed and the coolant replenished properly? If not, air could be trapped in the system and cause overheating issues which could lead to coolant loss. Any signs of coolant under the rear of the coach? One place also to look is up under the FRONT of the coach. It's likely that your dash heating system is like most, with coolant lines running from the engine up to the system's heater core and back. There are multiple hoses and connectors up at the front that can, over time, develop leaks....hoses can split and connectors can loosen. I recently addressed that very problem on my coach. Heater cores can also develop leaks. Any coolant drips under the front of the coach? Also look for dampness inside the coach on the floor in the driver/passenger areas. While some oil usage is normal, coolant usage is not. It is leaving for some reason. If you can't find it, you might want to visit your local Cummins dealer, bite the bullet and let the pro's find the reason....and they will. Maybe the actual fix will be something you can handle. Whatever it is, please let the rest of us know....thanks!

[jhs1881]

Hey all...thanks for your replies...It seems I need to do some more digging. Thinking back, when I blew that belt in Texas (that I was told ran the water pump) they had to add a lot of coolant; I'm now wondering if that is part of the problem. I'll be taking my MH to a pro to have it checked out If I can find one.
I called Cummins and they said it was a chassis issue; that they (Cummins) just supply the power plant to Spartan and Spartan is responsible for the cooling system, heater coils, etc. The dealer who sold the unit to me doesn't touch anything to do with the drive train (probably a good thing), won't even change the oil,..I'll be keeping everybody informed as I move along this sometimes frustrating road.

[HeapBigEngin]

Not sure what "a lot of coolant" is, but your bill shoud tell you how much they added. And that would be important to know. Big question.....did you have to add coolant BEFORE the belt problem, or after. If after, and they added a lot, perhaps air was/is still in your cooling system. Of course, ensuring that there are no external leaks would be my first priority and I sure wouldn't rule that out.

I looked over the Cummins Operation and Maintenance Manual for the 8.3 ISC in our Fleetwood m/home. The manual states that, after flushing/draining the cooling system, the "system must be filled properly to prevent air locks"; and that "during filling, air must be purged from the engine coolant passages". It also refers to the petcock on the aftercooler that must be used to purge aftercooled engines. It goes on to say that "The system is designed to use a specific quantity of coolant. If the coolant level is low, the engine will run hot. If frequent addition of coolant is necessary, the engine or systen has a leak. Find and repair the leak." That last sentence seems like a no brainer.....right?

This past summer, I had several repairs and maintenance issues adressed by my friendly Freightliner dealer. I also had the coolant flushed and changed. The tech I spoke to said that there is a definite process they follow to prevent coolant air locks, regardless of which diesel engine is in the unit. Been my experience with cars and light trucks that , most of the time, the vehicle will eventually purge air on its own....operating the heater would always help. Not sure about diesels. Maybe the coolant "loss" you are seeing is the result of air being purged after you've driven for awhile and then the m/h cools down. Not sure.

If you called the Cummins factory, I am not surprised at the answer. I would visit a local Cummins dealership that works on m/homes and talk to the Service Manager and/or a tech. Sure, they will want to see the unit; but they may be willing to share "an educated guess" or two. My local Cummins dealer works on a lot of m/homes, regardless of chasis, and the guys here have been very helpful. Just a thought. Good luck and please let us know what you find....thanks!

[jhs1881]

Thanks again for your helpful input....one of the main reasons I joined this forum was to be able to tap into other owners experience and knowledge.
Not sure as to the quantity of coolant ....they used one of those pumps that is powered by an electric drill...pumped the coolant out of a 5 gal bucket...not sure how much they put in. In any event, I'll be headed to the local Cummins shop and have the entire system flushed and fresh coolant added.... I'll let you know how I make out.
Thanks again.

[spike45]

Coolant replenishment is not uncommon in large vehicles like MHs and over the road trucks. In a sense your MH is a very comfortable OTR truck. Typical OTR trucks loose 12 gallons of coolant in around 16 months which equates to around 150,000 miles. Lots of coolant connections, use of silicon rubber coolant hose and incorrect hose clamp tightening are all contributors to coolant loss. Also, it you use the OAT coolants like CAT ELC or similar, those coolants leak faster than non-OAT HD coolants. If you are loosing a quart in a few thousand miles, pretty much normal for medium and HD service applications.

[sl29]

Spike 45 is correct....good post......I have the 8.3 and loose about 16oz-20oz every 4,000 miles.....I have checked and double checked for leaks.....had my oil checked for coolant...motor runs like a dream.....nothing......its just the nature of the BIG beast.....I'm sure the type of coolant and type of use contributes also.....mine was filled with the Cummings premix.

[Iron Man]

Cooling systems are a closed pressurized system. It is not normal to loose any coolant. If you are loosing coolant it has to go somewhere unless there is air in the system that is being "burped". They make pressure testers that can pressurize a cold engine and check for leaks or see if the pressure drops. If the pressure drops and there is no visible leaks then it is internal to the engine.

[wa8yxm]

Normal to have to add periodically.. Depends... There are some modern coolants that are designed to remain in the system for several years without changing coolant,,, You need to check more often but you should be able to go 5-10 years without adding..

Other coolants need to be changed at least every year, and you should never have to add save at coolant change.

[spike45]

Quote:

Originally Posted by Iron Man Cooling systems are a closed pressurized system. It is not normal to loose any coolant. If you are loosing coolant it has to go somewhere unless there is air in the system that is being "burped". They make pressure testers that can pressurize a cold engine and check for leaks or see if the pressure drops. If the pressure drops and there is no visible leaks then it is internal to the engine.

Systems that do not leak are atypical. Typical coolant loss occurs at silicon rubber hose to tube joints. Small leaks from water pump seals and osmotic separation of water from coolant through the walls of silicon rubber coolant hose. These are the standard leak points in large trucks (an RV is a large truck). Some systems leak little, most others do leak. The fact that a system is pressurized increases the leak rate. It is very advisable as stated above to use a pressure tester.....use a radiator cap pressure tester. Radiator caps from even reputable manufacturers are increasingly prone to not hold rated pressure or not be able to attain pressure rating. Bad pressure caps account for much coolant loss. It is not common for medium and heavy duty trucks (ISB - ISX motorhomes) to employ radiator overflow bottles like small LD cars and trucks. Too bad, it is a good idea but has never caught on with the OEM truck and chassis builders.

I have been in the maintenance business for 40 years. Leakage is all too common.

[spike45]

Quote:

Originally Posted by wa8yxm Normal to have to add periodically.. Depends... There are some modern coolants that are designed to remain in the system for several years without changing coolant,,, You need to check more often but you should be able to go 5-10 years without adding.. Other coolants need to be changed at least every year, and you should never have to add save at coolant change.

Those 'modern' coolants have been around for years. They were not always referred to as "long life" or "extended service" that is not until Texaco coined the long life term back in 1995 with the introduction of the HD OAT coolant for diesel engines. Then the industry all got on that band wagon and now call their products "long life".

I bet any who read this will think back when I say...did you change your coolant per the manufacturer's recommendations for your car or pickup? I bet not. You ran the coolant until the hose blew, radiator failed or water pump let go. Then you changed the coolant. You did that long before the introduction of Dexcool or the HD versions of 'long life' coolant.

So, you were using a long life coolant and did not realize it! It is still true only now you pay more for coolant with that label! Actually, the long life coolants now for MD and HD engines are far more robustly formulated for protection.

It is very uncommon to not have to add some coolant when you use your MH if you put on many miles. Cold leaks do happen. I refer you to the post immediately above where I listed silicon rubber hose a main culprit. You can identify most silicon rubber hose by its sky blue outer cover. The inner liner will be a dark orange color.

If you find leakage from silicon rubber hose to be too much to keep up with, switch to Gates Blue Stripe, EPDM coolant hose. It is a very good product and will stand up to cooling systems filled with Dexcool and similar HD OAT coolants such as Caterpillar ELC, Chevron Delo ELC, Shell Rotella ELC (not Shell Ultra).