Coolant that congeals

The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.

SUMMER2

Member
Joined
Sep 17, 2013
Messages
10
Location
CANADA
Vessel Name
SUMMER II
Vessel Make
34 MAINSHIP
I recently pulled the end cap off the heat exchanger on my Perkins 6.354. It appears the coolant has congealed? Slimy looking stuff around the tubes. Has anyone experienced this and what is the cause?
 
Sounds like the coolant has not been changed for about 30 years. I change mine about every three years. You need to flush the system and replace the coolant.
 
for lack of a better explanation....I agree with Boatpoker.

Someone may have added radiator stop leak or equivalent to stop an annoying or prevent a system failure...time to drain, clean, pressure check and see what you have....
 
Someone could have mixed different kinds of antifreeze that was not compatible with each other.
 
I recently pulled the end cap off the heat exchanger on my Perkins 6.354. It appears the coolant has congealed? Slimy looking stuff around the tubes. Has anyone experienced this and what is the cause?

I have seen congealed antifreeze in expansion tanks and don't really know what causes it. But usually the antifreeze is 4 or 5 years old and worn out.

Is this a Perkins Range 4 engine? Or the older 6.354, with the brass end cap, with a single brass bolt in the center, that covers the end of the tube bundle housing? Depending on which 6.354 version you have, they do have different coolers. On the older 6.354's, the brass end cap covers the seawater side of the system. I pulled one of these off on a boat that sat more than it ran and found small mollusks growing in it.
 
I remember hearing that if you don't use anti-freeze specific for Diesel engines, that it may congeal. Something to do with the nature of the greater cylinder force as a result of higher compression, all of this kinda fuzzy, but when I cleaned out my freshwater cooling side of the system, I specifically used anti-freeze designed for diesel engines.
 
Do you have zincs in front of the heat exchangers? The zinc residue can collect in the front of the tubes. How does the back of the heat exchanger look? Just thinking.
 
I remember hearing that if you don't use anti-freeze specific for Diesel engines, that it may congeal. Something to do with the nature of the greater cylinder force as a result of higher compression, all of this kinda fuzzy, but when I cleaned out my freshwater cooling side of the system, I specifically used anti-freeze designed for diesel engines.

American Diesel recommended plain old green antifreeze for Lehmans...

Some diesels are more subject to cavitation to the cylinder liners such as the 7.3L Ford of yesteryear and you have to monitor the silicate balance closely to reduce cavitation next to the cylinders (high compression bubble cavitation) but low enough you don't eat up moving parts like the bearings in your fresh water pump.

I have never seen "congealed" antifreeze even in blocks that have been sitting in junk yards. Something must have reacted with the antifreeze at some point. Not saying that it doesn't happen...but in my world it's rare and who knows what POs have done to sell boats or thought something they read was correct.
 
I recently pulled the end cap off the heat exchanger on my Perkins 6.354. It appears the coolant has congealed? Slimy looking stuff around the tubes. Has anyone experienced this and what is the cause?

What color gel are you seeing? I lost a head gasket on dozer engine several years ago that was letting small amount of oil migrate to the coolant....I noticed brown gel in radiator tank. The oil is at greater pressure than your coolant system and a pinhole leak may not allow coolant back into the oil for you to see milky oil during changes or on dipstick.
 
Last edited:
What color gel are you seeing? I lost a head gasket on dozer engine several years ago that was letting small amount of oil migrate to the coolant....I noticed brown gel in radiator tank. The oil is at greater pressure than your coolant system and a pinhole leak may not allow coolant back into the oil for you to see milky oil during changes or on dipstick.


This!!

I have no "diesel" experience with this but have seen first hand oil and antifreeze mix and congeal in gas engines. And 1 of the engines was running normally when the problem was found. Removing the oil pan upside down on the motor stand looked like something from a jello mold.

Have also heard of this happening when pink and green antifreeze where inadvertently mixed together in a friends Nissan. Jelled in the cooling system and was cleaned by thoroughly flushing with no lasting damage.
 
Some antifreeze types if blended will congeal. Always use the same stuff as was in there, if in doubt top up with distilled water, it mixes fine with any type coolant (except Evans). If old coolant, drain and flush multiple times with fresh water, then refill with your flavor of choice. If in doubt, do not mix types. Autostore stuff that claims "compatible with all coolants".... They are not. Not always. Crazy thing to put on a label.

Once you put coolant in your engine, cut the label off the bottle and zip tie it to the engine somewhere.
 
Thanks guys, I did top up the coolant last fall with the new purple antifreeze adding to the old green stuff not thinking of any reaction.
 
Coolant/antifreeze sold here is usually marked "Do not use with any other brand of coolant" I thought it was largely to promote sales by getting you to refill the whole system instead of topping up, but had an inkling you could get gelling if 2 specific types were mixed. Reminds me, got to flush the port motor.
 
Bruce, penrite do one that is 350,000klm or 6 year rated. It's pink and about $50 for 5ltrs. I dumped 30ltrs into my engine and heat exchangers but they were new items as you know.

Obviously we don't count klms but after reading what it had I could go past it.


Sent from my iPad using Trawler Forum
 
Last edited:
ImageUploadedByTrawler Forum1404828650.658430.jpg

ImageUploadedByTrawler Forum1404828698.141494.jpg


Sent from my iPad using Trawler Forum
 
If the a/f is brown or tan and looks like chocolate pudding, it is probably oil contamination from head gasket or oil cooler. I had that happen on a tug I worked on. After fixing the leak we ran water mixed with Calgon dishwasher detergent through the cooling system to get the gunk out. The calgon is designed to dissolve grease and doesn't foam like laundry detergent would. Worked great. Took several times to get it all out. Good luck.
 
Back
Top Bottom