Community Forums

smlranger · 02-20-2016, 08:44 AM

About 18 months ago, I had my local Cummins Coach Care drain, flush and refill my system with Fleet ES OAT coolant. Within 500 miles the coolant lost its red color and turned amber. Fleetguard's answer to that was they had some weak dye lots and the coolant should be fine. I sent a sample to the lab and the test results were questionable and the lab's recommendation was to replace it.

So, my Coach Care dealer did another drain and refill with new OAT coolant (I only paid for the coolant and they did not charge me for the labor). The used a combination of ES OAT premix and topped off with two gallons of concentrate to get the correct mix. The coolant in my sight glass was deep pink, light red.

Now, 3,000 miles later, the fluid in the sight glass is clear.... looks like water. I am perplexed and would like to test the coolant. However, my research reveals that the normal coolant refractometers will not test OAT.

Any suggestions??

DAJO · 02-20-2016, 02:04 PM

https://www.cumminsfiltration.com/ht...pleat/oat.html

Also when JG lubricants sent my OAT coolant to the lab they use they tested it as standard antifreeze and told me it was in need of change. After I changed it I realized what had happened and that I had wasted my money. I am sure I told them what it was but they either did not know what OAT was did not even look at information sent with test sample. I have used Global OAT in two engines and it seems to stay pink/red.

smlranger · 02-20-2016, 03:40 PM

I am in Tucson now and called the local Freightliner shop and they said they had test strips for OAT coolant. However, when I got there they only had bottles of 50 strips and wanted $45 for them. No single strips.

I had taken a sample with me so went to their service department and they agreed to test the sample with a strip. It tested to -60F, no nitrites (expected for OAT) and the final color on the strip tested OK for OAT.

Strange though, the sample I pulled from my coolant expansion tank was deep pink even though the fluid showing in the sight glass is clear... no color at all. Now I wonder if the sight glass is stopped up.

barmcd · 02-22-2016, 12:04 PM

Quote:

Originally Posted by smlranger

I am in Tucson now and called the local Freightliner shop and they said they had test strips for OAT coolant. However, when I got there they only had bottles of 50 strips and wanted $45 for them. No single strips.

I had taken a sample with me so went to their service department and they agreed to test the sample with a strip. It tested to -60F, no nitrites (expected for OAT) and the final color on the strip tested OK for OAT.

Strange though, the sample I pulled from my coolant expansion tank was deep pink even though the fluid showing in the sight glass is clear... no color at all. Now I wonder if the sight glass is stopped up.

I think it's probably normal. If you were to pour out a little antifreeze on a flat surface, it would look clear. Put it in a tall glass and it'd appear red. You are probably not seeing enough of a sample in the sight glass for the true color to be apparent.

**CountryFit** · 02-22-2016, 06:35 PM

my fluid is global final charge oat. the color is dark pinkish, like sedona clay (assuming you have been to sedona, az

).

the fact your sight glass being clear is probably that your fluid level is too low, there is no liquid in the sight glass tube; what you see is air

. add distilled water to the neck, start engine and check.

to take sample, i remember i read somewhere, do not take it from the expansion tank, rather, take it from where the coolant is actively flowing when engine is running. last time i did it by loosening the big hose clamp at lower left corner between the radiator and engine (if you stand facing the radiator).

smlranger · 02-22-2016, 07:18 PM

There is definitely liquid in the sight glass. Mine is about 6" tall and I can see the top of the column with a blob of goo at the top of the column. I can also look directly into the expansion tank with the cap off and see the level.... it is full to the bottom of the neck of the fill opening.

**CountryFit** · 02-22-2016, 08:35 PM

what color of the coolant do you see from the top? it shouldn't be clear.

replacement of a sight glass looks like an easy job... see here
http://www.irv2.com/forums/f278/chan...ce-237731.html

smlranger · 02-23-2016, 07:17 AM

Quote:

Originally Posted by CountryFit

what color of the coolant do you see from the top? it shouldn't be clear.

replacement of a sight glass looks like an easy job... see here
http://www.irv2.com/forums/f278/chan...ce-237731.html

Liquid showing in the sight glass is clear but what I pull out of the recovery tank is deep pink.

My sight glass is nothing like the one in the Entegra thread. Mine is like a flowmeter....about a 6" vertical glass tube with two attachments to the tank. When Cummins shop changed my coolant the second time, fluid in sight glass tube was deep pink and has only changed to a clear color in the past 1,000 miles or so. I think the tube is partially blocked and that is why I would like to get it apart and try to clean it.

I will see if Kevin knows how to disassemble or remove this one. If I can get it off the tank, I would plug the bottom hole and put one of the smaller sight glasses in the top hole.

Both my coolant recovery tank and hydraulic reservoir sight glasses are similar:

http://www.irv2.com/photopost/showph...49&ppuser=1549

MnTom · 02-23-2016, 08:11 AM

If your sight glass is like the ones pictured, then all you need to do is remove both the bolts (top and bottom). I don't know how you would get a sight glass to read correctly with just the top hole in use. You should be able to clean everything up and put it back on quite easily.

**CountryFit** · 02-23-2016, 09:38 PM

Quote:

Originally Posted by smlranger

Liquid showing in the sight glass is clear but what I pull out of the recovery tank is deep pink.

My sight glass is nothing like the one in the Entegra thread. Mine is like a flowmeter....about a 6" vertical glass tube with two attachments to the tank. When Cummins shop changed my coolant the second time, fluid in sight glass tube was deep pink and has only changed to a clear color in the past 1,000 miles or so. I think the tube is partially blocked and that is why I would like to get it apart and try to clean it.

I will see if Kevin knows how to disassemble or remove this one. If I can get it off the tank, I would plug the bottom hole and put one of the smaller sight glasses in the top hole.

Both my coolant recovery tank and hydraulic reservoir sight glasses are similar:

hydraulic fluid tank - iRV2.com RV Photo Gallery

a picture worth a thousand words. now i have the whole picture in mind.
it should be easy to take the tube out and clean, shouldn't it?

1) siphon out the fluid and save it for reuse. one or two gallon-size clean water jugs will do.
2) take out the lower bolt first. notice a hole in the center of the bolt and 2 or 4 holes in the middle of the thread. use a needle to probe the holes and clean. also notice there should be either a crush washer or rubber-oring.
3) if you see the hole(s) are blocked, after clean, you don't need to do the top one. otherwise do the same for the top one.
4) reverse the steps to put the tube back on, with new washer(s)/o-ring(s).
5) pour the fluid back in.
6) test for leak and color of the fluid inside the tube.

good luck.