[Sirrotica]

I was just thinking today about how many Pontiac owners experience O/H problems and I thought about a certain condition that I ran into with a customer car back in the late 1970s that may pertain to at least a few Pontiac O/H problems.

Chrysler at the time was making their infamous line of K cars. At that time in some of the cars they were using an iron block 1.7 L VW gas engine with an aluminum cylinder head bought from another competitor. They also were using a brass radiator in their cars. This formula of dissimilar metals could be easily duplicated by some people on this board. I.E. iron block, aluminum aftermarket heads, and a brass radiator.

I had a customer that had a K car that had the 1.7 engine and was O/H on the highway. I went through all my usual troubleshooting methods to try to find out why this car would O/H and was stumped. I sought out some help from an old timer that was second generation owner of a local radiator shop that was in my opinion a really good radiator man and was quite knowledgeable.

He asked me to bring the car down to him after talking to him on the phone and after doing some preliminary info gathering informed me that the radiator was to blame. I was puzzled how a low mileage 3 year old car could have a bad radiator already. He looks through some bulletins he has and digs one out and hands it to me and tells me to read over it. In essence the bulletin said that Chrysler had hit on just the right combination of metals that set up a electrolysis process that actually plated the inside of the radiator insulating it so it couldn't dissipate heat.

Looking at the inside of the radiator you wouldn't have a clue that there was any problem with the radiator whatsoever, no visual clues. I asked if he can clean out the radiator to save the customer some money, the reply was there is no compound that will remove the insulating layer from the brass radiator, Okay I said lets get a new radiator and try it. Upon installing the new radiator the problem disappeared. If memory serves there was a grounding system that would stop this electrolysis from ruining another radiator, but I can't remember all the details any longer. There was no antifreeze or additive at the time to reverse or stop the process either.

So if you've had this combination of dissimilar metals for a few years, it may be the problem and it gets worse over time. Just throwing this out so that maybe someone on this site can figure out their O/H problem. I hope this at least helps out one person solve their problems.

[dataway]

I think many people underestimate the engineering that goes into materials used in automotive engine. Take any system, dissimilar metals, add heat, add a corrosive environment and there will be a limited lifespan. In the Navy we spent a HUGE amount of time doing constant preventative maintenance of heat exchangers. In the big picture I would consider a radiator as a regular service replacement part.

Think about it... $400 every ten years or so to replace the radiator and maintain decent cooling efficiency is not really that high a price to pay.

[ponchjoe]

I wonder if the Evans waterless coolant would help with this situation or if it would make it worse...

[mchell]

I use two of these..... one in the intake crossover and one in the radiator drain petcock to ensure I won’t have corrosion isuues with aluminum and iron( mainly the aluminum pitting)......Not exactly the issue you are describing, but a sacrificial anode may help with that as well.

https://www.rotometals.com/flex-a-li...-4-npt-x-1-3-4

[dataway]

Good idea .... electric water heaters have them, they wouldn't last five years without the consumable anodes.

[Cardo]

Ames has them in the catalog now too. I believe they are charging $12.