Thread sealant on engine anodes?

[No Ice]

Should I use it and if so which is recommended. I don’t want to use thread lock just a thread seal to stop them leaking without over tightening.

No Ice. [emoji1160]

[a64pilot]

You won’t need it.
If you think you do use just a little bit of Teflon tape. You need to keep electrical contact of course, but I don’t think Teflon tape will isolate it, you could check with a multi meter if you were concerned

[boatpoker]

Break or interfere with the electrical connection between the heat exchanger housing and the anode, and your anode will have reduced effectiveness or be completely useless.

There must be 0.0ohms between the anode and the heat exchanger body.

The only way to test that is to install it, remove the end cap and then measure resistance between anode and exchanger...... more trouble than it's worth.

[model 10]

Dielectric grease is used in all kinds of connectors these days. It doesn't seem to cause any problems in some really complicated electrical systems.

[a64pilot]

Why can’t you measure resistance between the cap and the heat ex?
I’ve never bothered but bets it’s 0 ohms

[model 10]

I think you would need a Megohmmeter to measure any resistance. The typical meter on a boat doesn't come close to that.

[a64pilot]

I don’t think it’s that critical, at all.
A lot of anodes if not most are held on and connected with SS bolts, and SS is an extremely poor conductor of electricity.
Take this thing for example, they work, but the whole cable is SS, the clamp is SS, and nobody who wants a decent electrical connection relies on a clamp, but they are also most often connected to the boats grounding system, by clamping to the SS rigging.
They work, and if an extremely resistance free connection was required, they wouldn’t

https://www.boatzincs.com/hanging_anode_zinc.html

[Bill Seal]

Originally Posted by Ecos

I think you would need a Megohmmeter to measure any resistance. The typical meter on a boat doesn't come close to that.

Megohmmeter, as in Megger, used to measure Millions of Ohms of insulation resistance ???
Even a cheap Harbor Freight multimeter measures tenths of an ohm, enough to ensure contact,

[boatpoker]

Originally Posted by a64pilot

Why can’t you measure resistance between the cap and the heat ex?
I’ve never bothered but bets it’s 0 ohms

No you need to measure from the anode to the exchanger.
You can have 0.0ohms from the cap to the exchanger and still have and O.L. from the anode.

[boatpoker]

Originally Posted by Ecos

I think you would need a Megohmmeter to measure any resistance. The typical meter on a boat doesn't come close to that.

No, megohmeters are for measuring large volumes of resistance not small or zero resistance. There is no need for a megohmeter on a cruising boat.

[model 10]

That was my point, you would need a megohmmeter to find any resistance.

[boatpoker]

Originally Posted by Ecos

That was my point, you would need a megohmmeter to find any resistance.

No. you've got it backwards. An ohmeter is quite capable of finding resistance in the ranges we are talking about. i.e. 0.0 ohms is ideal but anything less than 1.0ohm is acceptable. There is absolutely nothing on a boat that requires readings in the megohm range. Even AC ground leakage (potentially fatal) testing requires nothing higher than the kilohm range which is also within the capabilities of a $20 meter.

[S/V Illusion]

Originally Posted by Ecos

That was my point, you would need a megohmmeter to find any resistance.

High resistance is of interest only in determining highly resistive circuits such as insulators. Any cheap multimeter works in this application

[a64pilot]

Originally Posted by boatpoker

No you need to measure from the anode to the exchanger.

You can have 0.0ohms from the cap to the exchanger and still have and O.L. from the anode.

If your talking pencil zincs you can only measure from the cap to the anode before installation and the cap to the metal it’s installed in after.
However I’ve never done that not even once, never heard of anyone doing it.

[model 10]

If the thread sealant causes any resistance you would need a meter that reads less than 1 ohm. The usual onboard meter does not go below 1 ohm, it only goes up from 1 ohm.