pencil zincs on a 120 lehman

Ahoy Mates,

Anyone know how many pencil zincs on a 120 Lehman?

And their locations?

Thanks!

Tom

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Mine has 3. One on the top left of the main heat exchanger, one on the left end of the transmission oil cooler and one on the input to the main oil cooler.

3 on mine too - one on each oil cooler and one on the engine heat exchanger.

Ditto here, and just had replaced.

Not all replacement oil and trans coolers have pencil zincs on them. I know I shouldn't tell you that until you spend an hour or so searching for them, but some don't. I've never seen a main heat exchanger that didn't have one though.

Ken

I must confess great envy. Having a 3126 Caterpillar, I must change no less than eleven pencil zincs. This includes the transmission cooler.*

"Not all replacement oil and trans coolers have pencil zincs on them"

True. Mine don't have them.

Thanks Guys,

I will be searching for them and replacing shortly!

Tom

Carl, If you unscrewed the bronze plug that holds the zinc pencil and the zinc remains in the exchanger you have two issues.

1) How to get the zinc out of the exchanger?* I would remove the bolt in the center of the end cap and take off the cap. you can than remove anything that remains from the zinc. You may or maynot need a new rubber gasket to replace the cap (if some green corrosion is building up along where the cap meets the exchanger housing you might want a new gasket on the end cap.

2) How to get the old zinc out of the bronze plug (clear the threads)?* I would buy a new one, only because I have tried in the past to melt the zinc out, or drill the zinc out, and it is too much trouble IMHO.

3) In the don't fix it if it is not broke catagory you could.* Take both end caps off the heat exchanger and flush it out (make sure it is not clogged) and replace both caps with new gaskets.*

#3 is optional.

JohnP

Old Stone wrote:
"*real close to the end of the exchanger (within 2 inches)"

Click to expand...

***********Carl,* Good plan to change the gaskets, if the green spot is 2" from the end on the top of the port side of the heat exchanger, you may have a drip from the exhaust elbow, check the raw water hose and fitting,and the bottom of the elbow for signs of trouble.

******** JohnP

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-- Edited by JohnP on Friday 15th of April 2011 06:53:27 AM

Old Stone wrote:
OK - Some help needed. After reading this thread, I checked my heat exchangers yesterday. Unscrewed the pencil head, and off came the head, no pencil. That is very happily sitting in the slot. Figured I would just drill down the center of the zinc and try to pull it out, but figured I'd

Click to expand...

*IMHO there isn't a prayer of a chance that you can drill a zinc in this situation.* However if it really is there then you should be able to grab the threads with a needle nose pliers or forceps and pull it out.*

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Ahoy Mates,

Just finished my zinc hunting. My CHB 35' is a 1981. I found only 1 pencil zing on the port side of the main exchanger. Does that sound right?

My situation is pretty much like Carl's. When I pulled the plug out the zinc was stuck in the hole. It was really like mush, maybe the consistency of rubbing compound. I poked and scraped the hole clean and bought a replacement. I also had some surface rust on the exhaust elbow and some green goop on the heat exchanger with some pitting there too. I "flossed" the gap between the elbow and the cooler with a rag and inspected. Both areas seem pretty solid.

A few questions:

1 - Do I need to remove the end cap, replace the gasket, flush out the cooler? I think I know the answer

2 - What is inside the exchanger? i.e. how does it work?

3 - What causes the green goop?

Would any remnants of the zinc "pass through" and out the exhaust if I don't disassembe/flush out?

Thanks!

Tom

1 pencil zinc, port side is exactly what I have. Sounds normal. Mushy consistancy is a sign that you got all the use out of that zinc, and IMHO you should replace the zinc sooner, when there is still a little bit of hard zinc left. I take the caps off and clean the main heat exchanger every 3-4 years. I change that zinc every 4-5 months. There is generally a small pile of goop right at the zinc spot. It has never seemed to cause me a problem.

Ken

Can you tell me what size the pencil zincs are? Thanks

CME#1 at West Marine or any Camp Zinc source....can be ordered with or without brass plug so be careful if online ordering.. I always keep a spare brass plug or 2 if the zinc threads break off.

But can't swear they will work in every heat exchanger...may want to take the brass plug with you.