I'm aware of electrolysis problems on the new generation engines , so many different materials , different liquids and so many electric and electronic components on the engine . Is there anyway to prevent , had anybody had the problem and how to troubleshoot ?
I think the biggest electrolysis prevention feature I can think of, is to make sure your aluminum radiator core is grounded to the engine bock and the coolant stays ph neutral.
The first time I came across electrolysis was about 15 years ago on a 3406C (I think). Long before Tier 3 was even a gleam in the EPA's eye ......... Also I'd suggest that the cylinder head has to be grounded to the block and the block to the chassis using separate ground cables for each one. if the engine has a spacer plate between the head and the block then I would ground the head to the spacer plate, then the spacer plate to the block, and finally the block to the chassis. in these days of alloy rather than brass/copper radiators it's also imperative to have the radiator grounded. Not sure about coolant PH, I always thought coolant was by design just to the alkaline side of PH neutral. Either way good quality coolant monitored correctly for condition on a regular basis is also a must.
I never considered the spacer plate, But I would think all those head bolts would ground the head. I do know most newer radiators are mounted with rubber mounts, and some have a frame ground... some. I prefer connecting them directly to the block just to make sure. And Nige, I think you are right about coolant being slightly to the alkaline side. IIRC that does help heat transfer and prevent some cavitation. Myself, Im a big believer in Cat or Texaco ELC. Anymore the labor involved in just mixing Anti-freeze and water is ridiculous, And if its not done properly... Its even more costly. I have seen that one happen. Very ugly.
I'm also a convinced fan of "proper" ELC. To me it's an absolute must. The electrolysis issue I came across with the 3406 engines (a fleet of 30 or so identical Kenworth tractors IIRC, it's a long time ago) was directly related to the fact the spacer plate was not grounded, or at least I choose to believe so. Certainly the problem went away on every truck just as soon as we grounded the spacer plate.
What are you defining as electrolysis? Are you speaking of liner pitting or something else?
John, this issue (or at least the first time I came across it) goes back to the late 90's on a fleet of Kentworth tractors equipped with 3176B engines. It goes back to long before the issue of Tier 3 was even a gleam in the EPA's eye...... Initially the problem was diagnosed as pitting and a lot of time and effort was put into looking at coolant (ELC was just coming on to the market), its condition, thermostats, engine operating temperatures, etc, etc - even intake & exhaust systems ...... however nothing we did made any difference. Nobody made a connection that every time an engine blew a head gasket or suffered a water leak or whatever type of failure it had that the spacer plate had to be replaced because of "pitting" along with all the other parts during the repair. The key to everything was when one day someone looked at the "pit marks" in a spacer plate under a loupe, then under a microscope. The bottom of each pit was a deep blue colour, some were even purple. We dug up a load of spacer plates from previous repairs and every one without exception showed the same characteristics, so we came to the conclusion that electrolysis was taking place between the liners and the spacer plate using the coolant as an electrolyte. The original factory engine installation used a single 4/0 ground cable from the cylinder block to a ground stud on the chassis. We added 2 additional ground cables, one from the cylinder head and one from the spacer plate to the same stud and the problem went away.
That is interesting Nige. Thanks for the advice.
This post got me thinking, Then I had one of those "midnight revelations". I didnt consider the fact that the spacer has a gasket above and below with minimal metal to metal contact, if any. Bingo, aluminum spacer becomes the "sacrificial anode" in the system. Even with the best in coolant management thats going to be the eventual outcome.
I need to correct something. The engine were in fact 3176B's as per post #7. When I originally wrote post #3 I thought they were 3406 but then I went back and looked at my notes.....sad sack that I am I still have them - it was 1998.....!! Although TBH I would imagine any engine with a spacer plate would perform the same way. Personally I wouldn't bank on the cylinder head bolts being a good enough ground for the head and the spacer plate.
That is interesting. I have never worked on that series engine so wasn't familiar with that problem. I have seen plenty of liner pitting on engines as old as early sixties. Basically everything with a liner was subject to that which included Cummins, Komatsu, Case and so on. I had not seen pitting on the D8K and D9H spacer plates so wasn't aware that it became prevalent on other motors. Back then liner pitting was thought to be a chemical and mechanical process and no one related it to an electrical issue. I have seen plenty of aluminum radiators and never had a corrosion problem as long as the proper coolant was used and changed at the manufacturer's recommendation. So going back to the original post, what are we looking for now days that indicate an issue on a machine we might be looking to purchase?
Liner pitting is a different thing entirely AFAIK. It's generally caused by cavitation resulting from localized boiling of the coolant. Usual culprits are poor quality coolant or poor coolant flow round the engine, especially around the liners. That's why the first time I came across electrolysis it didn't immediately register what was actually going on inside the engine.
Why would there be coolant between the liners and the spacer plate? I would think the locator dowels would ground the head and the spacer plate to the block. Bob
Because the liners run right through the spacer plate and also all the coolant passages between the block and the cylinder head run through the same spacer plate. So there is coolant everywhere within the spacer plate itself, some of which is going to find its way to the liner/spacer plate interface. We thought the same as you that there was enough "steel to steel" contact with the head bolts so that everything could be grounded via the cylinder block, apparently this was not the case. Maybe installing a separate ground cable on the cylinder head was a bit like overkill, but by the time we got to that point we were thoroughly sick of the problem. All I can say is that with the 2 additional ground cables the electrolysis issue disappeared and never came back.
One question that I hope is not to obvious. How did you connect the ground wire to the spacer plate? Just drill and tap a hole in the edge while engine was assembled? Has this "update" been made standard on newer engines? And would this be good idea to do to any engine that uses an aluminium spacer plate? Okay that was three questions , but who's counting!
We used a blank boss on the spacer plate. Because the engine was torn down (and we were fitting a new spacer plate anyway because the old one was "pitted") there was no problem drilling and tapping into the boss. We did make sure we didn't drill too deep then we Loctited a stud into the spacer plate. The cable terminal was held in position using a couple of brass washers and a Nyloc nut. Would I recommend it on any engine..? Not unless the symptoms of electrolysis were present. Has the engine been re-engineered..? Well if you count being discontinued as being re-engineered then yes. The replacement C-series engines don't have a spacer plate.
This is my problem on a C9.3 acert engine , year 2012 , 3300 hours , allways run on ELC coolant , big damages to the engine , we put new exhaust cooler , radiator , turbo , now it is running again , of course there is no reason the new cooler will last , what can i do to troubleshoot this ?
What is the engine installed in..?
Caterpillar 966k