Coolers on yanmar

[SILENTKNIGHT]

I have a 6LY 370. I wanted to open the end caps on all the coolers to give a quick peek to see if any zinc are at the bottom and clean. will antifreeze pour out when i open the cooler end caps? We havent did any winterization yet.

I have alot of extra gaskets to reapply when i close it up? and will reinsert new zinc as well

 

[Dougcole]

No, antifreeze will not pour out when you open the end cap, those tubes you see behind the end caps are where the raw water passes through.


In my experience you don't have to replace the gaskets every time you open the cap, but if the gaskets have not been replaced in awhile or seem stiff, it's a good idea to replace them.


Look for little pieces of zinc that broke off and fell into the cooler when you have the caps off.


Doug

 

[SILENTKNIGHT]

Thank you for that response I am going to open them up take a look and even use a small wire brush if there is any corrosion..

 

[porman]

After 17 years the seals on our 6LY Yanmars were starting to drip in a few places. Replace them all. They aren't that expensive.

 

[Comodave]

I would have new seals on hand when you open it up. It may never have been opened up and the current seals may be really hard.

 

[Derek]

Just pulled the end cap on new to me Mainship 430. Have the heat exchangers off to the radiator shop for acid bath and pressure test.

 

[jimdavi]

Geez! Good that you checked. Overheat waiting to happen.

 

[DavidM]

When you replace zincs, tighten them up with pliers on the zinc and a wrench on the brass nut. This will minimize chances of the zinc falling off inside in the future.

Also try to replace the zincs before they get more than half wasted, preferably one third.

On that engine I kept a mental log of intervals to replace. It went something like this:

Main heat exchanger, after cooler- 6 months.
Transmission and engine lube oil cooler- about 12 months.

YMMV.

David

David

 

[Derek]

Before and after.

 

[firehoser75]

Derek,
Good job! This illustrates why I opine about the need for "regular" full off engine servicing rather than the "Barnacle Buster" type of band-aid fix. Often there are anode pieces, impeller pieces, and other sea debris that can lead to a very costly engine overheat. By the time that the standard overheat alarm goes off, damage can already have occurred. Also very important, we want to KEEP the various fluids where they are supposed to be, and not leaking into areas where damage can occur (like seawater in your tranny, engine oil, antifreeze, etc.). The only way this can be reliably done (minimizing risk) is by pressure testing!! Again, can't be done just by using BB. As part of a full off engine service, it is always a good idea to at least consider replacing all seals, O rings, etc. as they do have a "service life" and as such don't last forever. and usually they are not that expensive.
I also recommend installing 2 additional alarms related to overheating. A Borel exhaust temp alarm and a raw water flow alarm. The flow alarm will even provide warning to avoid impeller damage (in many circumstances), and the very first place an overheat will be detectable is on the exhaust hose, providing an early warning of a pending overheat prior to costly engine damage occurring. JMHO.

 

[rgano]

Makes you wonder how much else was ignored on your new boat. Hoses, belts (including timing), and ALL fluids should to eyeballed with probable replacement in mind. It would be wise to check every single alarm on the Yanmar. A recent overheating of a 6LPA happened with no audible alarm due to "messed up wiring" as quoted from the mechanic. Owner luckily heard some odd noises and noted unsatisfactory engine performance before shutting it down and luckily saving it. Also, thumbs up on adding the exhaust alarm.

 

[Derek]

Makes you wonder how much else was ignored on your new boat. Hoses, belts (including timing), and ALL fluids should to eyeballed with probable replacement in mind. It would be wise to check every single alarm on the Yanmar. A recent overheating of a 6LPA happened with no audible alarm due to "messed up wiring" as quoted from the mechanic. Owner luckily heard some odd noises and noted unsatisfactory engine performance before shutting it down and luckily saving it. Also, thumbs up on adding the exhaust alarm.

You have hit upon my worse case scenario. I did change impellers, oil, checked tranny, new zincs, new PSS dripless Shaft seals, new bow thruster, new sea strainers, put 2 gallons of distilled water in the batteries, replaced genny battery, checked all fluids In genny and will tighten belts tomorrow. Taking her out for a 2-3 hour shakeout tomorrow w fresh pads under the engines. If it’s an uneventful trip hoping to bid adieu to Atlantic yacht Basin on Friday and begin heading south. Fingers crossed y’all.

 

[PierreR]

That does it, I am going to look at both of mine.

 

[lipets]

How many hours are on that engine?

 

[Derek]

2300. Been 2 days and 80 miles. Temps much better and not a drop of anything under the engines so far.

 

[ssurabus]

The regular maintenance discussed in this thread is a must to keep coolers in good condition, but using traditional style anode pencils that un-thread and break upon removal often results in one step forward-two steps back - and coolers that can end up looking like the photos posted above. I've been using new anodes on my engines that solve the problem of zincs getting stuck in coolers. The anode plug acts as an anode puller that:

* prevents torque from being transferred to the rod so it gets pulled straight out along its strongest direction (with no breakage).

* prevents a stuck rod from un-threading from the plug and being left behind (there are no internal threads)

My twin engine 40T has 15 zincs between the Yanmar and the Kohler. Changing zincs is now easy, fast and frustration fee. The zincs come out every time with just the turn of a wrench. I've made them available because they've made such a difference for me and I've seen so many other people struggle with the needless hassle of zinc maintenance. I am the designer and happy to provide details upon request.

 

[Steve DAntonio]

Thank you for that response I am going to open them up take a look and even use a small wire brush if there is any corrosion..

Don't use a wire brush, it can leave behind traces of metal that can be galvanically incompatible with the cooler alloy. You non-metallic brush, ScotchBrite etc.

More here https://stevedmarineconsulting.com/heat-exchanger-tlc/