gummy substance on engine following coolant flush

[thinwater]

I’m with dj - that doesn’t sound legit at all. The coolant is mostly just ethylene glycol in water. There’s nothing there to create a voltage potential at all.

Actually ...

It is not impossible to have a voltage due to a wiring error (nothing to do with coolant condition dirrectly). I've seen this when electric fans on cars are replaced, for example. It will cause MASSIVE corrosion in very short order and may any coolant turn orange with rust.

If your coolant gets rusty after electrical work, something to check. Not common, but sometimes disastrous.

I wonder if the internet wizard had a coolant disaster related to a wiring problem and completely misunderstood what was happening.

 

[Ralph Johnstone]

It is not impossible to have a voltage due to a wiring error

So you're saying a wiring error where a battery is accidentally plugged into the circuit where none is meant to be ?

Now THAT'S a serious mistake which would likely result in a bad, if not complete short to ground. I would expect other aspects of this faulty wiring to rear their ugly heads before the corrosion started to appear.

It is not impossible to have a voltage due to a wiring error (nothing to do with coolant condition dirrectly).

In addition, there would still not be any evidence of a voltage (even with the battery accidentally in there) if both electrodes of the multimeter were submerged in the coolant without touching any of the surrounding metal as outlined in post #15.

Just baseless internet rambling without the entertainment value as far as I'm concerned. I much prefer the internet ramblings about the nearby comet CI/Atlas which we're told may contain beautiful 6 ft. alien female amazons who are here to propogate their species using earth's males. Now THAT'S interesting .

 

[dLj]

The measurement is taken between the engine block and the coolant, sorry about the typo.

That's a totally different situation...

I'm guessing that as the coolant deteriorates and the ph rises it becomes more alkaline and this causes a potential difference between the coolant itself and the metal of the engine. I was wondering if @thinwater could explain.

OK - I'll keep my mouth shut...

Also ph test strips are actually very cheap and that is a really quick test.

Just a FYI - this is far better/easier than trying to measure corrosion potentials via a mutlimeter...

dj

 

[Johnb]

OK - I'll keep my mouth shut...

Without your comments I would not have found my typo.

 

[thinwater]

So you're saying a wiring error where a battery is accidentally plugged into the circuit where none is meant to be ?

Now THAT'S a serious mistake which would likely result in a bad, if not complete short to ground....

Not necessarily. I was not the mechanic. But ...

My understanding is that the radiator was only connected to the engine with hoses. The radiator was mounted to the frame with isolators or a plastic subframe. Thus it is possible to have the two units at different potentials with only the coolant completing the circuit. Not enough conductivity to make a short, but enough to do a LOT of damamge.

The engine and the radiator should have both been grounded. But if the wire polarity is reversed somewhere bad things happen. I have also seen this happen in industry with control circuit (DC) wiring.

Sudden corrosion many places on a boat can be associated with a wiring error.

 

[Ralph Johnstone]

My understanding is that the radiator was only connected to the engine with hoses.

I didn't see that statement from the OP but then again, maybe I'm just going blind.

How or why any engine mfg. would want to electrically insulate the radiator (heat exchanger in this case) from the block beats me. When I worked on my hex. on a Yanmar 2GM20F, it was bloody heavy with all of the brass tubing and heads. You would have to do a lot of fooling around to bolt the hex. to the block (or some other structure) without making an electrical connection.

The engine and the radiator should have both been grounded.

Yes, lets just agree to say say "No, it was not insulated from the block, it was grounded to the block."

This whole discussion of electrical conductivity indicating the condition of the coolant has been one whacko internut fairy-tale from the get go. I can well imagine you've got much better things to do than discuss this crap and I've got bulbs by the sack load which need planting before the first freeze hits. Let's save our time for something a little more worthy of debate.

 

[thinwater]

This is NOT internut ranting. Search the subject. There are both galvanic and stray current possibilities.

Coolant conductivity and consequences have long been and active subject of discussion among coolant experts with OEMs and coolant manufacturers. It is one of the reasons distilled water is used. Make sure you have good, low resistance grounds.

 

[Ralph Johnstone]

There are both galvanic and stray current possibilities.

OK, we're on a little more solid ground here looking for stray voltage, although it's very unlikely you've got galvanic current in there as the shell of the hex. is usually of the same material as the tubes to avoid galvanic corrosion and its associated current.

It is one of the reasons distilled water is used. Make sure you have good, low resistance grounds.

Maybe I'm not correctly following you here but everything around the hex. is well grounded even if the coolant is drained from he hex. I'm going to presume the bolts holding the hex. to the block are the major conductors for grounding the hex.

As far as using distilled water in the 50/50 coolant, using distilled water will actually decrease (however slightly) the conductivity of the coolant due to the LACK of total dissolved solids (TDS) as compared to tap water. And this of course doesn't amount to a hill of beans because the hex. is well grounded. Distilled water is preferred because it lacks the TDS such as Mg and Ca which tap water contains and precipitate out on the heat exchange surfaces over time.

As you previously pointed out, the only time you would expect to see V in a hex. is when you accidentally touch a (+) wire to the casing.

It is not impossible to have a voltage due to a wiring error (nothing to do with coolant condition dirrectly). I've seen this when electric fans on cars are replaced, for example.

The only reason I can see for what looks like oxide around his hex. connections is that once you have an external leak, metal is going to corrode as there is an endless supply of O2 to overcome the reducing chemicals in the coolant. Corrosion guaranteed.

So, after all this, I have yet to see what could possibly induce a stray current in the hex. of a PROPERLY constructed engine without glaring electrical problems. PROPERLY being the key word here. There are an unlimited number of elecrical problems you could introduce here to cause a stray current problem.