coolant age/viability

As we are getting ready to take the boat to the Bahamas from Norfolk, VA, I am going over the engines with a fine tooth comb.

My question concerns coolant. I have no record from the previous owner of coolant being changed. The mechanic who adjusted the valves told me that the boat's blue coolant was extended life, which was good for 10 years. I question how he knows that. The boat has 1250 hours and was commissioned in 2003. The engines are Cummins 6BTA5.9.

How do I tell if the coolant is still good, or whether I need to change? Obviously not changing coolant would save some work and mess. I can by test strips but am unsure what numbers I should be looking for.

Thanks in advance,
Gordon

Gordon J said:

As we are getting ready to take the boat to the Bahamas from Norfolk, VA, I am going over the engines with a fine tooth comb.

My question concerns coolant. I have no record from the previous owner of coolant being changed. The mechanic who adjusted the valves told me that the boat's blue coolant was extended life, which was good for 10 years. I question how he knows that. The boat has 1250 hours and was commissioned in 2003. The engines are Cummins 6BTA5.9.

How do I tell if the coolant is still good, or whether I need to change? Obviously not changing coolant would save some work and mess. I can by test strips but am unsure what numbers I should be looking for.

Thanks in advance,
Gordon

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If it were me, I would change it out and then you know the age of the coolant. It isn't a big of a job to do.

Yup that is an option, however sticking a test strip in coolant and reading the results is even easier, if that is a viable option.

Penrite make test strips for all coolants including long life types. They test for concentration, pH, and alkalinity. Instructions are fairly simple and included with the kit.

Penrite Oil | COOLANT TEST STRIPS

Would anyone consider looking in the engine manual for a coolant change interval? Nobody knows what the engine needs better than the manufacturer and trying to save the few dollars a coolant change costs is foolish if you are risking a $25K (or more) engine.

My coolant is supposed to be changed every two years so that's what I do.

WesK said:

Would anyone consider looking in the engine manual for a coolant change interval? Nobody knows what the engine needs better than the manufacturer and trying to save the few dollars a coolant change costs is foolish if you are risking a $25K (or more) engine.

My coolant is supposed to be changed every two years so that's what I do.

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The certified Cummins mechanic told me that in my year engine that the company was using extended life coolant. Two years is how long you get off the green stuff. Current extended life coolant in stores claims to be good in cars for 120K miles or five years. I used to own a trucking company and learned to change fluids when the fluids were worn down/diluted or had some other issue. Testing can point you in the right direction.

While in the Army, we regularly tested oil in all diesel engines. Sometimes trucks would only get a couple thousand miles a year on them and with testing, we would learn that we could go often for years without changing.

I test oil now, but still change at the 250-hour interval as stated in the manual.

Gordon

AusCan said:

Penrite make test strips for all coolants including long life types. They test for concentration, pH, and alkalinity. Instructions are fairly simple and included with the kit.

Penrite Oil | COOLANT TEST STRIPS

Click to expand...

AUSCAN,

Thanks. It appears the strips are only sold in California. I am sure I can find an American version somewhere. The instructions were much clearer than I seen on another product.

gordon

Gordon J said:

The certified Cummins mechanic told me that in my year engine that the company was using extended life coolant. Two years is how long you get off the green stuff. Current extended life coolant in stores claims to be good in cars for 120K miles or five years. I used to own a trucking company and learned to change fluids when the fluids were worn down/diluted or had some other issue. Testing can point you in the right direction.

While in the Army, we regularly tested oil in all diesel engines. Sometimes trucks would only get a couple thousand miles a year on them and with testing, we would learn that we could go often for years without changing.

I test oil now, but still change at the 250-hour interval as stated in the manual.

Gordon

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The difference between land based engine applications and marine is that the marine engine coolants can easily be contaminated by raw water leaks within the X-changer over time.
Even longer life coolants are not recommended for the same duration of service in marine diesels.
Please consult a Cummins engine manual and or take a look over at sbmar(dot)com.

How about Cummins Coolant Test Strips? They might work pretty well in Cummins diesels

Using a certified Cummins (or any brand) mechanic is fine but he is a mechanic who went to factory school, not one of the engineers who designed the engine. There will be a factory specification or maintenance interval for coolant type and change intervals.

The cost of coolant changes is minor compared to the potential for engine damage.

If you ask the right questions and understand what the engine requires for coolant....it isnt complicated.

Yes if you are using a specified coolant per instructions and test it using certified test strips...you can feel safe your engine is protected.

Except in a few instances, coolant is not one of those things that will kill an engine quickly.

WesK said:

Would anyone consider looking in the engine manual for a coolant change interval? Nobody knows what the engine needs better than the manufacturer and trying to save the few dollars a coolant change costs is foolish if you are risking a $25K (or more) engine.

My coolant is supposed to be changed every two years so that's what I do.

Click to expand...

Gordon,

A bit of drift towards WesK's point - I have a crankcase breather on my Volvo Penta. It costs around $125, and VP now recommends a 100-hour interval, reduced from 200-hours when the manual was printed. Replacement of the engine is in the neighborhood of $40,000 for the block, plus labor. One can find pages and pages of internet discussion about how to clean and reuse this $125 crankcase breather, which is amusing to me. I once read some advice like WesK offers - that the crankcase breather is darn cheap compared to an engine replacement because a clogged oil nozzle allowed a catastrophic failure. I choose to follow this advice. There is a cost to run these machines properly. When I sell this boat, the fact that the 5000-hour engine has been maintained meticulously will add value. When I buy our next boat, proper maintenance wil be a primary consideration.

I suspect you would not regret renewing the coolant, as well as anything else in question, prior to your offshore voyage.

I just changed my green coolant last week. VP calls for a 2-year renewal interval.

Best Wishes,

Jeff

I use what LarryM suggested.. only way to know for sure.

All the large diesel engine manufacturers have test strips and coolant change intervals and other good guidance. No voodoo or opinions, just read the manuals.

smitty477 said:

The difference between land based engine applications and marine is that the marine engine coolants can easily be contaminated by raw water leaks within the X-changer over time.
Even longer life coolants are not recommended for the same duration of service in marine diesels.
Please consult a Cummins engine manual and or take a look over at sbmar(dot)com.

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Wouldn't leaks in a heat exchanger show up when testing the coolant? I actually looked at SBmar.com and did not see anything on coolants. Maybe I missed it.

psneeld said:

If you ask the right questions and understand what the engine requires for coolant....it isnt complicated.

Yes if you are using a specified coolant per instructions and test it using certified test strips...you can feel safe your engine is protected.

Except in a few instances, coolant is not one of those things that will kill an engine quickly.

Click to expand...

Changing coolant every couple of years is essential for any engine, especially marine engines due to the fact that many boat engine rooms run hotter than they should due to poor or even no engine room ventilation and it all adds up to degradation earlier than later,

For the doubting few below is from a Volvo exhaust manifold sitting for two years only (in a hot engine room in a hot climate, you can clearly see where the seal area's have been eaten away (Two years!!) as i fitted this manifold brand new so know the history,

Cheers Steve

CaptSteve53 said:

For the doubting few below is from a Volvo exhaust manifold.....

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Volvo?
That says it all doesn't it?

I tend to agree (known as the Green Death for just that!), but in this case Aluminium is Aluminum and new Aluminium as that, the coolant by the way was the newer (Long Lasting Type) color red from memory,(NOT GREEN)

Many of the modern engines need SCA , to prevent the cylinders from being holed by cavitation.

Be sure the test strips will test for acid , not just SCA levels.

FF said:

Many of the modern engines need SCA , to prevent the cylinders from being holed by cavitation.

Be sure the test strips will test for acid , not just SCA levels.

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Before you may ask SCA is :
QUOTE:
Supplemental Coolant Additives are vital for the health and longevity of any diesel engine. Diesels, particularly the Ford Power-stroke, are prone to a problem called cavitation (or liner pitting). Both cavitation and corrosion can result in shorter engine life if the SCA level of your coolant is not monitored and maintained. The proper level of a chemical concentration of 1.5 - 3.0 UPG (Units Per Gallon) should be maintained in your cooling system at all times. For maximum protection be sure you begin with high quality make-up water (test with the ACU5050 CTS-5 Cool Check water test) and then check your SCA level every four months using Acustrip CTS-3 or CTS-4 test strips.

It's based on the principal the pistons in your engine move up and down about 2,000 times a minute. While they move vertically, the crankshaft is performing a completely different movement by rotating horizontally. These contradictory movements will cause your engine's liners in some cases to vibrate a lot. Although the outer wall of the liner is surrounded by cooling fluid, its inertia creates tiny vacuum pockets, causing bubbles of vapor to form on the liner wall. When the liner vibrates back, these bubbles collapse under an enormous pressure and take small chunks out of the liner. Eventually you may have a liner/ block failure,

Saying all that in 100's of strip and rebuilds I personally have only ever seen a handful cases, but when it does happen it looks like borer have attacked a portion of the liner (normally small in diameter) and if I didn't know better would have said a poor quality casting!, as above for what ever reason some engines are more prone than others?

In some engines it shows up as tiny bubbles in the fresh water system which is commonly miss-diagnosed as a leaking head gasket,the small (tiny) hole allows air into the water but not big enough (at first) to let water into the liner,

Cheers Steve

Coolant for modern diesel engines is actually more complicated than it would seem, even if you ask questions. Volvo has published papers on the subject (I lost the link) talking about the cavitation and other issues. They caution that once a particular type of coolant has been used, an engine can never be flushed well enough to switch to another type (in the case of Volvo coolant, from green to orange).

In my experience and opinion, proper maintenance (as based on factory specifications) is a very minor part of the total cost of boating. I do what is supposed to be done, the way it is supposed to be done and when it is supposed to be done.

The bottom line is; Do you believe what the manufacturer says or what some stranger on the Internet says?

It's your boat and your checkbook.

For a fun exercise, pull a pint or so of coolant and compare it side by side in a glass jar to new coolant. Then pour it through a coffee filter. The visual comparison and entrained residue is a good guide for harmful effects of increased viscosity and decreasing heat transfer capability.

As previously mentioned, not a bad idea to change it out per the book. Both calendar time and hours are stated in the owner's manuals I have read over the years. Test strips are not necessarily indicative of all coolant effectiveness criteria according to the engine builders I've talked with for off road applications. We found aggressive coolant changes quite helpful at high altitudes and in desert climates.

Changing it based on engine manufactures suggestions may be not as applicable as the coolant manufactures recommendations.

Normal life, extended life, extended life with charged coolant filters.....etc

They have engineers also working hard on product performance.

Sure, dont be a pioneer in guessing with new formulations but if I followed Lehman manual recommendations, I would be searching antique auto stores for recommended coolants and oils.

If you have a new engine and dont mind paying OEM prices then its easy and why even ask on the forum?
But in that tween world where things change faster than what manufacturers can keep up with....understanding your engines needs and product perfomance in my mind shows intelligence over cattle behavior.

Who do you think found and responded to Ford's cavitaion issue? Plus I think Caterpillar had found it even earlier? Yep, plenty of local mechanics as well as after marketeers.

S41 said:

If it were me, I would change it out and then you know the age of the coolant. It isn't a big of a job to do.

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It's probably $120 an engine for 5.5 gal gallons of Fleetguard coolant per engine. For piece of mind I used Fleetguard Restore Cleaner/Flush before the change out. The blue Fleetguard specs for ES-PS and ES-EG is 150,000 miles or 4000 hrs.

I dont know how the 4000 hrs applies to low use marine application. Maybe you could call Fleetguard. If it applies then maybe the test strips are all you need. Be aware the test strips have a a shelf life.

If it were me I would do the change out knowing I didn't have to do it again.

Just a thought regarding the coolant and the effects of cavitation on sleeved cylinders as relates to the OP's question about his Cummins 6BT.
Since the 6BT isn't a sleeved cylinder, they're not prone to cavitation, and as a result the coolant requirements for the 6BT aren't nearly as fussy as with other diesels. As others said, the cost of the coolant in comparison to engine repairs is minimal. However, temper that with the 6BT's coolant spec. If your coolant is extended life and well exceeds the spec, the case for change out might not be as strong. You can always send a sample of the coolant out to have it tested, that would be relatively inexpensive and give you a more conclusive assessment.

Gordon J said:

As we are getting ready to take the boat to the Bahamas from Norfolk, VA, I am going over the engines with a fine tooth comb.

My question concerns coolant. I have no record from the previous owner of coolant being changed. The mechanic who adjusted the valves told me that the boat's blue coolant was extended life, which was good for 10 years. I question how he knows that. The boat has 1250 hours and was commissioned in 2003. The engines are Cummins 6BTA5.9.

How do I tell if the coolant is still good, or whether I need to change? Obviously not changing coolant would save some work and mess. I can by test strips but am unsure what numbers I should be looking for.

Thanks in advance,
Gordon

Click to expand...

My rules are change when the owners manual says or sooner if indicated by test strips or otherwise. Since you don't know when it was last done then you can't just based on time. I would get test strips, but I would change the coolant now, if convenient, as a conservative measure and to establish a time line for going forward.

Be careful with judging coolant by color. There are different coolant chemistries out there and one needs to use coolant chemistry the engine maker specifies. Color is not a indicator of the chemistry.

For instance, my Ford diesel uses a GOLD colored coolant from Ford which is an extended lifetime coolant. Ford also has a GREEN coolant that can be used in my engine but it has a limited lifetime compared to the GOLD coolant.

My JD tractor, which has a Yanmar engine, uses a GREEN colored coolant. JD's GREEN COOLANT is the same chemistry as the Ford GOLD coolant.

I have used the JD coolant for years in the Ford and in the JD/Yanmar.

The JD GREEN coolant is not the same as the Ford GREEN coolant and neither is even close to the Prestone gas engine GREEN coolant.

Later,
Dan

dannc said:

Be careful with judging coolant by color. There are different coolant chemistries out there and one needs to use coolant chemistry the engine maker specifies. Color is not a indicator of the chemistry.

For instance, my Ford diesel uses a GOLD colored coolant from Ford which is an extended lifetime coolant. Ford also has a GREEN coolant that can be used in my engine but it has a limited lifetime compared to the GOLD coolant.

My JD tractor, which has a Yanmar engine, uses a GREEN colored coolant. JD's GREEN COOLANT is the same chemistry as the Ford GOLD coolant.

I have used the JD coolant for years in the Ford and in the JD/Yanmar.

The JD GREEN coolant is not the same as the Ford GREEN coolant and neither is even close to the Prestone gas engine GREEN coolant.

Later,
Dan

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In the case of the OP, we are talking Fleetguard. It is blue.

Does it really matter to coolant?

fryedaze said:

It's probably $120 an engine for 5.5 gal gallons of Fleetguard coolant per engine. For piece of mind I used Fleetguard Restore Cleaner/Flush before the change out. The blue Fleetguard specs for ES-PS and ES-EG is 150,000 miles or 4000 hrs.

I dont know how the 4000 hrs applies to low use marine application. Maybe you could call Fleetguard. If it applies then maybe the test strips are all you need. Be aware the test strips have a a shelf life.

If it were me I would do the change out knowing I didn't have to do it again.

Click to expand...

I have read all of Tony's articles about marine life versus non-marine life. However, it seems to me that the cooling system is a sealed system, and barring any leaks in heat exchangers, it would seem that the stress on coolant would be the same on a Marine diesel as on an over the road diesel.

Someone earlier in this thread suggested that it would be good to change the coolant because there might have been, or is a leak in one of the heat exchangers. I would posit that if I have a leaky heat exchanger new coolant is the least of my worries.

Still, just for the sake of edification, it might not be a bad idea to call fleet guard and query them about the need for changing the coolant when it it has only 1000 hours on it versus the recommended 4000 hours.

Feedback

I just wanted to get back to everybody and let you know what I did. I bought fleet guard test strips, which test for all the vital elements in the coolant. When I first looked at these online it was not clear that they test for SCA.

As it turns out they test for freezing point, molybdate and nitrite. Where molybdate and nitrate intersect on their chart gives one the level of SCA. In my case I am good to go. This is one less task for me to undertake before heading south.

Gordon