Heat exchanger ??????

[Ken Cross]

Hi everyone. I've removed the end cap from my heat exchanger on my Yanmar 2GM20F and the photo shows one tube is completely blocked, but none of the others seem to have anything in them. Having said that I have only opened one end. I think I know, but i'll ask anyway. Is that normal?

Also at the output side between the exchanger and the mixing elbow is this goofy plastic thing. What's this?

Inquiring minds didn't really want to know, but ......

Ken

 

[Stu Jackson]

1. Rydlyme

2. Vented loop (Google it, saves a lot of retyping)

 

[Charles Erwin]

Ken

Others will comment on the exchanger. Most would recommend take it apart "rod" it out (clean out the tubes with a small bore rifle cleaning brush.)

As to photo 2, since the circuit is "between the exchanger and the mixing elbow" the device is a siphon brake/vented loop. This device breaks a possible siphon of seawater which could happen in the seawater to the mixing elbow path when the motor is at rest - thus protecting the exhaust manifold from siphoned sewater and in turn protecting the exhaust valves from back flooding by seawater.

Charles

 

[Mark Maulden]

I don't know Yannies but take the other cap off and see if the same tube is blocked. It might be capped off from a previous repair of a leak....

 

[petersea]

Yes it appear one tube is blocked but do as other have suggested clear with a gun tube brush. Both ends must be removed to clean properly. Looks like the o ring also has a nick in it so I suggest new o rings also when putting back together. I guess my real question is what made you pull it off to check it ? Is there a problem ?? Overheating ?? One blocked tube should not cause major problem. I would be surprised if it even increased the operating temp at all. If it is just general maintance my hat is off to you for your good maintance. If you ever had a impeller break up it could be no more then a piece of it that clogged the single tube, that will then get blocked with debris or deposits. In an extreme case you can remove the core and have a radiator shop boil it out and clean both sides of the core (does not look like this is needed from your pictures )
The "goofy plastic thing" aka "vented loop" is very important. There is a air vent on it and I suggest you check occasionally to verity it is not clogged. Keep us updated !

Check out this you tube video of vented loop explanation from Jamestown Distributors, while not your brand (you have a vetus)same principle applies https://www.youtube.com/watch?v=_GCWtUvRTLY

 

[Ken Cross]

Thanks all for the3 help.

I replaced the impeller. The impeller hub was separated from the rubber causing an overheat.

After the impeller change I noticed steam from the exhaust. When I disconnected the water tube from the missing elbow then restarted I saw no water flow. I disconnected the input to the heat exchanger and had flow there just with the starter motor. My plan is to rod out the HX and the mixing elbow. I'm just trying to figure out if the blocked tube should be left alone or if I should clear it.

Ken

 

[woodster]

if it was blocked by someone repairing it i would leave it alone as one tube will not cause you any harm as you have only lost about 6% of the cooling capacity in that segment and if you go messing with that tube you may open up a can of worms and that part of the exchanger can cost as much as $700.00 depending where you purchase it

 

[Chris Patterson]

Ken, on that Yanmar, I'm gonna bet your riser elbow is clogged.

 

[Ken Cross]

Ken, on that Yanmar, I'm gonna bet your riser elbow is clogged.

Thanks Chris. I also intend to clean out the elbow, but the restricted water flow was before the elbow as that's where I disconnected the line to check for flow.
Ken