When was the last time you......

ccxnola wrote:
...did a drain, flush and refill the cooling system???

I'm planning our trip for later this year and just for grins to pass the time on this 4th of July weekend, I dug out the owners manual to go thru the maintenance checklist.

YES, I am very disciplined about the oil and filter change as recommended, and I check tire pressures before every trip and at least every day of travel. But the antifreeze?? when the engine is cold, I just look at the level to be sure it is OK. BUT, I think the last time the rig was drained, flushed and refilled was about 2006 - right after our escape from Katrina trip to Northern LA.

The owners manual for my Cummins C6 recommends a cooling system flush and refill every two (Yes - 2) years!!! Just one more little thing to be done in preparation for our fall trip!!!

I have it done every 24-mos. I use Vehicle Manager to track and remind me of maintenance.

There is no "here is how often to change coolants" based on engine. Engine makers do not spec or install coolant. And if they did, for your Cummins 8.3 liter, the recommendations would likely be based on experiences for OTR trucks-- irrelevant for RV use.

The chassis maker and/or owner choose the type of coolant-- there is a wide range in coolant life:

Older generation/less expensive: "Low silicate for diesel with added SCA/DCA. Normal life 3 years with annual testing and replenishing of SCA/DCA which is used up to protect the cylinder liners.

Newer generation/more expensive originally but less expensive over the life of the coolant: OAT-based coolants. 6 year maintenance free (unless you drive over 300,000 miles, then add a "booster".

SOOOO, what coolant do you have in there? If the "old" kind, when was it last tested? Test strips are available to check: SCA concentration, freeze point and pH.

Here are the test strips we use at all Diesel RV Club Rallies, and I also have at the FMCA Conventions (at the Caterpillar Engine Maintenance Seminar):http://www.wixfilters.com/Lookup/PartDetails.aspx?Part=22873

The only bad news with the test strips is that they come in boxes of 12 four packs and have less than a year shelf life. DO NOT USE AN EXPIRED STRIP, RESULTS CAN BE ERRONEOUS. So buying a box makes sense if you will be getting together with other DP owners.

wolfe10 wrote:
There is no "here is how often to change coolants" based on engine. Engine makers do not spec or install coolant. And if they did, for your Cummins 8.3 liter, the recommendations would likely be based on experiences for OTR trucks-- irrelevant for RV use.

Wolfe - My reference for the two year time-frame is the Cummins publication #3605963 (4/95) Quick Reference Guide - "RV Maintenance and Operation"

The information there also includes use of the test strips and specific measurements of minerals in the coolant.

So that you do not over-spend, you might also check on the coolant change recommendation from your chassis maker and/or coolant manufacturer. I think you will find that 3 years is a more common recommendation for "regular" coolant, 6 years for the OAT-based coolant.

Agree that changing every two years will only harm your pocket book.

Were I in a quandary about what to do, I would test the coolant. If SCA, freeze point and pH test in-line, I would not discard it.

I have a GM "Lifetime coolant" system.. Till it tells me otherwise it should not be drained and flushed.

Sadly it will in about 2 years.. but that's another story.

Ours will be done the first time this fall with the oil change. Rig is three years old. Had it tested last fall and it was good. The engine is under warranty for another 2 years. Rather be safe than sorry and void any repairs if something happens. I'll have the thermostat changed then too.