ISB Coolant Change

[chasfm11]

I typically refrain from placing a similar post in multiple forums but thought this one was worthy of making an exception.

Upfront: I'm an IT type guy and prone to over-analyzing everything. Please bear with me.

History:
The former owner of our coach had the local Freightliner dealer do work, some under warranty, to deal with overheating. Some of that work was the replacement of some hoses and the coolant in the radiator system. This happened just before we bought in 2004

In 2006, I paid a local shop $500 to replace the coolant. According to the invoice, they:
- brought then system to operating temperature then dumped it
- refilled it with water, brought to operating temp again then dumped agin.
- refilled with coolant to -27 degrees F level. (two gallons of coolant)

This week, I called Freightliner Custom Chassis about the total capacity of my system. While they claim ignorance about the heater hoses and the heater core, the tech agreed that the total system was about 10 gallons. That is consistent with reports from other ISB owners. The FCC tech, however, reported that he had personally drained ISBs and the best that he ever got out was 7 gallons. His recommended procedure was:
- bring the system to operating temperature,shut off the valve to the heater then dump it
- refill with 50/50 mix
He claimed that is what is done at the Gaffney center all of the time.

Here is what I think that I'm dealing with:
- the RV is now 8 years old and, upon examination, the hoses need to be replaced.
- based on what I now know, the system probably wasn't drained and flushed properly on any of the previous coolant service actions.

My plan is to:
- bring the system to operating temperature then dump it, leaving the heater valve open.
- refill/flush with plain water, bring it to oper. temperature and then dump it again, leaving the heater valve open and the heater switch in full operate position. Thrugh the flushing, I expect to get all of the existing coolant expelled.
- refill with distilled water, bring to oper. temperature and dump again, leaving the heater valve open.
- remove and replace all hoses.

Here is my dilemma. I'm not going to use 50/50. I know that the system capacity is about 10 gallons which means that when I start the refill process, if I believe that I've gotten the coolant out via the hose removals and flushing, I should start with 5 gallons of coolant before adding any more distilled water. I also know that I will likely be adding coolant on and off afterwards as the air works its way out of the system following the change. I plan to do as good a job of measuring the final dump of the system as possible before the hose replacement but suspect that it is going to be inexact. Since I will have flushed the system with water, however, I'm not sure that measurement makes any difference.

I'm doing all of this on the premise that it is time to do this job completely and correctly, not band aid it again.

Are there holes in my logic?

Thanks,

Charlie

[chasfm11]

I typically refrain from placing a similar post in multiple forums but thought this one was worthy of making an exception.

Upfront: I'm an IT type guy and prone to over-analyzing everything. Please bear with me.

History:
The former owner of our coach had the local Freightliner dealer do work, some under warranty, to deal with overheating. Some of that work was the replacement of some hoses and the coolant in the radiator system. This happened just before we bought in 2004

In 2006, I paid a local shop $500 to replace the coolant. According to the invoice, they:
- brought then system to operating temperature then dumped it
- refilled it with water, brought to operating temp again then dumped agin.
- refilled with coolant to -27 degrees F level. (two gallons of coolant)

This week, I called Freightliner Custom Chassis about the total capacity of my system. While they claim ignorance about the heater hoses and the heater core, the tech agreed that the total system was about 10 gallons. That is consistent with reports from other ISB owners. The FCC tech, however, reported that he had personally drained ISBs and the best that he ever got out was 7 gallons. His recommended procedure was:
- bring the system to operating temperature,shut off the valve to the heater then dump it
- refill with 50/50 mix
He claimed that is what is done at the Gaffney center all of the time.

Here is what I think that I'm dealing with:
- the RV is now 8 years old and, upon examination, the hoses need to be replaced.
- based on what I now know, the system probably wasn't drained and flushed properly on any of the previous coolant service actions.

My plan is to:
- bring the system to operating temperature then dump it, leaving the heater valve open.
- refill/flush with plain water, bring it to oper. temperature and then dump it again, leaving the heater valve open and the heater switch in full operate position. Thrugh the flushing, I expect to get all of the existing coolant expelled.
- refill with distilled water, bring to oper. temperature and dump again, leaving the heater valve open.
- remove and replace all hoses.

Here is my dilemma. I'm not going to use 50/50. I know that the system capacity is about 10 gallons which means that when I start the refill process, if I believe that I've gotten the coolant out via the hose removals and flushing, I should start with 5 gallons of coolant before adding any more distilled water. I also know that I will likely be adding coolant on and off afterwards as the air works its way out of the system following the change. I plan to do as good a job of measuring the final dump of the system as possible before the hose replacement but suspect that it is going to be inexact. Since I will have flushed the system with water, however, I'm not sure that measurement makes any difference.

I'm doing all of this on the premise that it is time to do this job completely and correctly, not band aid it again.

Are there holes in my logic?

Thanks,

Charlie

[Ecker]

My ISB was changed at Gaffney several times over six years and each time the amount used was 30 qts.

[GaryKD]

I just changed my coolant and followed the process mentioned in your OP. The only difference, and beware, it took me 9 flushes to get the color of the dump down to a very pale green. I had about 60 gallons of contaminated water, in the back of my truck, to take to the recycle station! . My situation may be different than yours. I have an ISC and was taking out the green and putting the red colored Final Charge. My cooling system is 10 to 12 gallons. When recharging I used concentrate of 6 gallons. Then filled with distilled water. I've had to add very little additional coolant. When needed, I added the 50/50 mix.

[chasfm11]

Thanks, Gary. I'm expecting to have about 40 gallons of contaminated fluid before I'm done (10 gallon system capacity).

I'm making several amendments to my procedure, based on other inputs:
1. Initial draining will be cold, not operating temperature.
2. The hoses will be replaced before the final distilled water flush.
3. I will be using a chemical cleaner for one of the tap water flushes.

I have 5 gallons of coolant to add. I tend to understand what Gaffney told me - that I'm not going to get everything out, even taking off the hoses. After the system is filled the first time, if I do add more, it will be 50/50.

Charlie

[chasfm11]

Leo, if my math is correct, your 30qts is 7.5 gallons - exactly what FCC told me what they drained out of ISBs. My concern remains that if the capacity of the system is 10 gallons - as they agreed that it is, that may still be about 3 gallons or almost 1/3 of the system's capacity as old fluid and whatever contaminants that it contains circulating in my system. Perhaps that isn't a problem, but I'd like to do a little better. Perhaps I can.

[Rapid Ray]

I'm not a diesel guy so inform me please. You mentioned you will refill with distilled water. Is this recommended for this type of system? I thought that "hungry" water might not be a good idea.

[GaryKD]

Hi Ray,
Diesel or gas, distilled water is the only water to add to a cooling system (and batteries). The 50/50 blend of the coolant of your choice should contain distilled water, for the water 50%. Tap water contains too many substances. Some may be bad for the cooling system parts.

[Ecker]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by chasfm11:
Leo, if my math is correct, your 30qts is 7.5 gallons - exactly what FCC told me what they drained out of ISBs. My concern remains that if the capacity of the system is 10 gallons - as they agreed that it is, that may still be about 3 gallons or almost 1/3 of the system's capacity as old fluid and whatever contaminants that it contains circulating in my system. Perhaps that isn't a problem, but I'd like to do a little better. Perhaps I can. </div></BLOCKQUOTE>
________________________________________________
I checked Cummins Quik-Serv database for my old ISB engine and the engine only coolant is 9.5qts. Therefore the balance of 20.5 has to be from all other points so it must be draining fairly well.however, I went back to an old web site I developed in 1999 for the Discovery motorhome, which contained contributions from FCCC as well as individuals and see that the person covering coolant change does say that one should have a receptacle capable of holding at least 10 gals when changing coolant.

[chasfm11]

The problem is today that I need to be able to have containers capable of holding 10 gallon each time I dump the system. I'm hoping for only 3 dumps but it could go more. At between 7 and 10 gallons per dump, that is a lot of fluid to recycle afterwards. Fortunately, I have access to a place that can do that.

[GaryKD]

I saved every gallon jug we brought into the house for over 1 year. It's amazing how many of those things a family uses.

[sparetire]

Just did my radiator on my DP. I got a 5 gallon bucket at Lowes and made 4 gallons of a 50/50 mix of anti-freeze and distilled water. My system Cummins 6CTA, 8.3L, takes 10 Gals total. After flushing and draining the block, I used 2, 4 gallon batches of mix. Thereafter I fiqured I'd just mix up the remaining 2 or so gallons a gallon at a time (1/2 antifreeze bottle and 1/2 gal of distilled water). I got about 3/4 of the next 1 gallon mix in and it was full. After driving about 25 miles, it needed the remaining 1/4 gallon to top it off. Guess I had a gallon of water in the system or better, the 10 gallons is a nice round number for the coach builder. Either way I'm happy with the results.

Take care,
Sparetire

[chasfm11]

I just finished the job today.

The good news:
1. I bought parts from FCC in Gaffney rather than the local dealers. The upper radiator hose was $189 from the Dallas Freightliner and $73 from Gaffney
2. The hoses were easier to put on than most cars. The surge tank end of upper radiator hose and the hose from the "y" below the block were the most difficult. I don't have two hours effort in all of the hose removals and replacements.
3. I'm glad I did it myself. I could never have paid a professional to do what I ended up doing. I figure that I have 6 hours labor in the total job and about $250 in parts and supplies.
4. My town had a recycling day today and I was able to recycle the anti-freeze from this change and the oil and transmission fluid from the power steering, transmission and differential work that I just finished, too.
The bad news:
1. I used the Cummins recommended cleaner and thought I'd never get it out of the system. The old coolant dumped in 3 tries. I have 5 cycles on trying to remove the cleaner. I finally flushed the system, just allowing fresh water to run from a hose into the top of the radiator and out the heater petcock. I'm glad that I used it because there was crude in the system but it sure is a pain to deal with.

Only time will tell if I got all of the air bubbles out of the system so that it doesn't start needing more coolant mix periodically. I also cleaned the radiator/charge air cooler throughly while I was doing the coolant change. I should be good to go now.

[speed racer]

Remove the block drains and you will only have to flush it once.