Cracks in coolant hose

Earlier this week as I was working on the anodes, I noticed this on the underside of a coolant hose which returns engine coolant from the hot water heater heat exchanger to the underside of the coolant return junction tube.


It looks pretty bad and I get the impression that it may be leaking coolant. Here is where it is located on my Cummins QSB 5.9L engine.

So I need to replace these (likely original) coolant hoses. So that means draining all the coolant from the engine tracing, removing, replacing two 20' runs of coolant hose. The second hose is that other black hose to the left of the return hose circled. It exits the side of the exhaust manifold.

I feel there should have been a valve on those hoses at both ends of those hoses. With such a long run, if there was any rupture to either the supply or return hose the engine would lose all coolant with no quick way to resolve the problem. If there were valves at either end of the hose then heater circuit could be isolated from the coolant system and the engine would be functional again with just the addition of coolant.



So I have a few questions;
1. Any tips on draining and disposing of the coolant?

2. Any suggestions for fittings to add a valve to the hose at the engine and water heater side?

3. What may I have failed to consider so far?

Not meant to be snarky but don't overthink it. Replace in kind, new hose, new marine full ss clamps, and enjoy another 10 years or so. Couple of drain pans and buckets. Most marinas have a disposal tank. IMO would not suggest valves. Too easy to accidentally shut something and cause a problem.
It's actually good that you can see it. Some applications have braided cover which looks fine but the hose underneath looks like this.

Greetings,
Mr. d. Must the coolant be replaced or can it be pumped into drums and re-used?
Valves IMO would be a good idea. Others (smarter members) may see the fallacy in that.
Use better (AWAB type) clamps. Good job for spotting that.

First acquired 5 or more empty gallon jugs. Then find an easy controlled point to drain the coolant. After you have easily drained as much coolant as possible cut the hose at about the mid point and drain into a bucket.

No need to add valves. You won’t be doing this job again.

My 6CTAs have a drain petcock. I drain it into as large a pan as will fit in the area. I have a 12 volt pump that I transfer it from the pan into a 5 gallon Jerry can. Agree on the AWAB or ABA clamps. I also agree on no valves, they can fracture from the vibrations of the engine. Just use a good quality hose. When I changed my coolant I went with Cummins Lifetime coolant.

Thanks the the quick replies. No coolant or oil disposal at my marina so I will need to take it to the closest hazmat collection site. That will mean putting it all in empty jugs. Since I don't have any, I may use a couple 5 gallon buckets then use the empty coolant jugs from the new coolant.

This engine was installed by Cummins to replace the original engine they broke. They used Cummins coolant at the time. Not sure if I can reuse it or not. I will check to see what the lifespan is supposed to be on. They left me a couple gallons at the time.

I see mine is a minority opinion on the isolation valves. I will reconsider that idea.

Think about not draining. You will loose the coolant in the hoses to the water heater heat exchanger, no way around that. Rough in the hoses no connections yet at water heater or engine. Leave them a bit long. Clamp the existing hoses near the engine. Vice grips, C clamps anything that will pinch it shut. Break the hoses loose at the water heater. Attach the new to the water heater. Secure the run as needed. Mark the engine end for length. Cut it. Remove the stub and pop the new on. With luck you won't loose much. Top off and burp the cooling system and all should be good. Worth a try.

I like the idea of repurposing the coolant. On the other hand your local auto repair shop can take your coolant for you. They might charge you a handling fee but will save you time and fuel.

I put shutoff valves (90 degree ball valves)on mine when I did my repower with the 6 BTA.. Drilled a hole in the handle and used a wire tie to keep them from accidentally closing.

I have no idea if the hose is a quality hose or not, but its origin leaves me with doubts.

If I was to replace it, I would install at least one set of valves near the engine and use a very high quality hose.

Route the hose carefully and provide chafe guards and restraint as required.

If it ever fails, do you think your high coolant alarm/gauge will alert you in time to save major engine damage?

Check for your local area, but in many places it's permitted to dispose of coolant down the toilet. Ethylene glycol biodegrades so it breaks down fine in most sewage treatment plants.

I don't know your engine, mine is the V555M, now old and with 32 litres of coolant..
Take a good solid look at the engine for any signs of drain petcocks. THere should
be some at various places
Carefully examine the engine, both sides, for drain petcocks. There will be some on manifolds , the block , heat exchangers. They will likely need a funnel with a hose attached.

You might ask a Cummins dealer.

Start with the HIGHEST drain cocks. Use some funnels and REMOVE THE TOP MOST DRAIN COCKS into the funnel which leads the coolant to a bucket. If need be work and clamp a hose onto the funnel so the hose leads to the bucket.
Have two collection buckets ready as there may be more than the two gal that want to come out.

On my much older engine, I use a 2 gal to drain collection and then empty that into 2x5 gal buckets out on the dock. When the 5 gals are filled I then bang the lids on. The lids can be removed when you get to the collection depot.
Never spilled yet.

I suggest though that you find and ask the collection depot what they require. The last time I went they wanted the used AF in 2 gal jugs for their handling. Find out first.
Actually the same for used oil.

Be ready with some , I suggest the Scot Blue, paper shop towels for clean up of spills.


After my first time, dumped into the bilge, I rigged small, LOCKING handle type, ball valves and nipples to each petcock location with a hose that lead to a bucket. for collection.
The Petcocks were discarded. I initially used FORGED brass fittings to adapt the ball valves and a drain nipple to the petcock locations.. After reading that even forged brass is subject to vibration breakage I changed those to steel hydraulic fitting still useing the locking ball valves. The steel hydraulic ftgs. are much stronger than brass, even forged brass.
If you can secure your ball valves straight into the petcock openings with no elbows or extensions then that should be good. I could not, I needed a 90o elbow and some nipples to extend the drains.

Brass done 1985/86, change to steel about 2000.

For what it is worth I offer my experience.

I installed valves on my 2 Cummins and one John Deere engines.

Friend of mine had the heat exchanger fail in the water heater. The 40 PSI domestic water pressure pushed all the coolant out of the engine, pressure tested his hoses, and all the coolant and 20 gallons of domestic water through the radiator cap and overflow bottle.

If nothing else, I'd like to isolate the problem and be able to get back underway.

Ted

Mine hold about 6 or 7 gallons each engine. I opened the petcock and drained it into a pan and as the pan would get full I would turn on the transfer pump and pump it out of the pan and into a Jerry can. Fairly easy but took 2 people to do it. An auto repair shop charged me $1 per gallon to dispose of the old coolant. Cummins has 2 versions of coolant. The standard has to be tested for the SCA level. The extended life is good for the life of the engine per Cummins and doesn’t need to be tested for SCA level. They both cost the same so it was a no brainer as to going with the extended life coolant. I just filled the engines with coolant and ran them until they got hot, let them cool down and topped off the coolant, didn’t need much more though.

When I replaced my water heater I also replace a reroute hoses. I also though about putting in valves but did not. Would introduce another breaking point for a low risk issue. I mean if you regularly check your hose, like when doing your oil change, and if using good quality hose, risk of failure is pretty low, no very high pressure there.
About coolant, I drained it in a jug and reused it, no waste except few drops.
Also before reconnecting hoses, I hold them high (well my wife did) and filled them with coolant to avoid large empty/air section. Closed the hose with my thumb and quickly reconnected it.

L

The coolant that Cummins used in my reman engine was the "Lifetime" coolant so I may be able to save and reuse it.

Does your engine have a coolant filter? Mine do so the coolant stays cleaner.

Comodave said:

Does your engine have a coolant filter? Mine do so the coolant stays cleaner.

Click to expand...

I don't think so.

I wasn’t sure if the 5.9 had a filter or not.

I would replace with different hose - either Trident or Shields wet exhaust hose. I suspect that cracking is an incompatibility with ethylene glycol, or it's just junk hose.

I would definitely add shutoffs. If a leak should ever develop in the heater loop, you want to be able to shut it off and continue to use the engine.

And I would definitely reuse the coolant unless there is something obviously wrong with it. Draining it out and pouring it back in won't change it.

Once you have the engine drained and the hoses disconnected at the engine, use a shop vac to blow through one hose with the other hose in a bucket. That will blow the residual coolant out of the hoses and hot water tank. There will likely be a fair amount of coolant still in there.

Turtle Blues said:

Not meant to be snarky but don't overthink it. Replace in kind, new hose, new marine full ss clamps, and enjoy another 10 years or so. Couple of drain pans and buckets. Most marinas have a disposal tank. IMO would not suggest valves. Too easy to accidentally shut something and cause a problem.
It's actually good that you can see it. Some applications have braided cover which looks fine but the hose underneath looks like this.

Click to expand...

I fully agree, the only problem with the hoses is that they are too long new. Whoever does your maintainence needs an interview without coffee !

Irish Rambler said:

I fully agree, the only problem with the hoses is that they are too long new. Whoever does your maintainence needs an interview without coffee !

Click to expand...

I can arrange that. I talk to myself all the time.

twistedtree said:

I would replace with different hose - either Trident or Shields wet exhaust hose. I suspect that cracking is an incompatibility with ethylene glycol, or it's just junk hose.

I would definitely add shutoffs. If a leak should ever develop in the heater loop, you want to be able to shut it off and continue to use the engine.

And I would definitely reuse the coolant unless there is something obviously wrong with it. Draining it out and pouring it back in won't change it.

Once you have the engine drained and the hoses disconnected at the engine, use a shop vac to blow through one hose with the other hose in a bucket. That will blow the residual coolant out of the hoses and hot water tank. There will likely be a fair amount of coolant still in there.

Click to expand...

Good suggestions. I have decided to put in valves. My initial reason was as you describe, a way to deal with a possible leak in the 30' of hose in the heater circuit.

Another reason is that it would allow me to get the boat running much sooner. I can drain the coolant, install the valves, and refill the coolant and have the boat running again. Then I can replace the hoses to the water heater over time.

dhays said:

I can arrange that. I talk to myself all the time.

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I guess you'll be drinkinking tea instead of coffee now
Seriously, I keep a file and register every detail however small regarding the whole boat with a section dedicated for the engine and note the usual time/date/quantities etc but also the type/length/date of hoses that are replaced along with all part no's. In the autumn and I carry out a minute detailed inspection of all thing like hoses, its easier done then when the admirals not on board as I can get full access to every part.
I know I'm a bit obsessive but touch wood I've never broken down.

dhays said:

Good suggestions. I have decided to put in valves. My initial reason was as you describe, a way to deal with a possible leak in the 30' of hose in the heater circuit.

Another reason is that it would allow me to get the boat running much sooner. I can drain the coolant, install the valves, and refill the coolant and have the boat running again. Then I can replace the hoses to the water heater over time.

Click to expand...

If I may risk one advice, changing the hose should be the first step. Even if you have valves in place, I would not take the risk to blow one, meaning that you will need to clean a big mess and if you don't notice it immediately you could also damaged your engine.
Just my 2 cents.

L

dhays said:

... I talk to myself all the time.

Click to expand...

Best way to an intelligent conversation by far. That offending hose is just aged, few things last forever, though the manufacture location may be relevant.

Greetings,
Mr. dh. Just had a thought...How about mounting any valve OFF the engine. Meaning: Engine-hose-valve-rest of the hose run. The valve might be hard mounted to a stringer or bracket. Any destructive vibration should be insulated by the rubber hose betwixt engine and valve. You would lose some coolant but still less if no valve.

dhays said:

I talk to myself all the time.

Click to expand...

This makes total sense. There are many times when one is in need of expert opinion.

Lou_tribal said:

If I may risk one advice, changing the hose should be the first step. Even if you have valves in place, I would not take the risk to blow one, meaning that you will need to clean a big mess and if you don't notice it immediately you could also damaged your engine.
Just my 2 cents.

Click to expand...

Great advice Lou, but my thought was that I can drain the coolant, install the valves, and then close them. The heater supply circuit will be empty and unused then until I can replace the hoses, to avoid the risk you mentioned while still being able to use the boat.

It will mean that there will be no hot water via the engine heat or the furnace. I'll only have hot water via the electric element until I get the hoses replaced and refilled. That make sense?

RT Firefly said:

Greetings,
Mr. dh. Just had a thought...How about mounting any valve OFF the engine. Meaning: Engine-hose-valve-rest of the hose run. The valve might be hard mounted to a stringer or bracket. Any destructive vibration should be insulated by the rubber hose betwixt engine and valve. You would lose some coolant but still less if no valve.

Click to expand...

Another good suggestion. However, Tony Athens (Seaboard Marine) uses them on the Cummins engines all the time so I don't think that the vibrations will be an issue. At least that is my thought.