Organic coolant in a 328

You will need to be more specific. OAT or HOAT coolant. There are additives like 2-EHA that are know to attack solder on older style radiators.
Organic Acid Technology - TechWiki (seloc.org)

 

Coolant additives are reactive to the materials the radiator, water pump, and engine are made of.

You should always use the recommended type of coolant.

 

Stick with the green stuff, Ethylene glycol. It has worked for the last 36 years without incident.

 

Yep, worrying about another solution (NPI) for which there is no problem.

 

When I took apart my 328 water pump, thermostat there was this jelly like material. I assumed it was because someone had either let the coolant sit for a VERY long time and or mixed different coolant types. I am kind of worried about nooks and crannies in the coolant system of this jelly stuff. How do you flush everything out? I remember a shop putting tide laundry detergent into my coolant system after my Porsche 944 had oil mix with coolant. What is the best way to flush everything out including the heater cores?

 

There are several products/kits specifically designed to flush cooling systems. Just pick one up at the parts store that is suitable for Aluminum engines and follow the directions.

The gel could be caused by mixing incompatible coolants, by a head gasket leak, OR by leaving some types of coolant system flush in the system for an extended period. So again, if you buy a flush product, follow the directions!

 

Not so simple anymore, the old style green coolant by Prestone has been reformulated as a type of hoat coolant. I have not had much luck confirming if the new green remains best for our old radiators, head gaskets and such. Prestone just repeats claims their universal coolant is fine for everything, with no explanation of the chemistry.

 

I have never questioned the labels - if they say they are OK for AL, I take them at their word. I suppose if you are looking for the best possible AF for long-term use with long-interval changing, the formulation may be important. But with the typical routine changes that Ferrari recommended and that most people here seem to follow, Prestone Green seems as good as anything else. As far as being OK for AL, although I haven't read all the labels, I suspect that most, if not all AFs on the shelf are OK with AL since AL is so common nowadays in engines.

Along with switching to changing oil cold, I also recently changed my antifreeze method from buying concentrate and mixing 50/50 with distilled water to buying premixed AF. With plenty of on-line water arguments about distilled vs tap vs de-mineralized, vs ionized, I decided the AF manufacturers knew better than I (or any internet boffins) did about what sort of water to use.

 

It is not the aluminum, it is the brass and solder in the old radiators. There is also a brass impeller on the OEM water pump. I don't think modern cars use any brass, copper or solders, hence the formulations have changed.

Good old plain green original formula is probably still available from truck suppliers. Might still be available from the main brands, but not stocked at retail the way it used to be.

 

OK, I can understand that - it was a common concern in Marine cooling/antifreeze. Penray, as well as several others was a common AF for marine use. They talked about the PH as being the big issue. If below 8.5 it was hard on ferrous metals, AL, copper and brass. If above 11 it was hard on AL and solder. So testing the coolant for PH was a common thing and adding additives as necessary to maintain the PH. I suppose it would be the same with these engines.

 

Exactly.

Still baffling that most auto manufacturers have their own blends of antifreeze, with quite large differences in ph, you see the make specific brands in the main stores. Yet why would eg. Honda with an all aluminum engines and cooling sytems differ from eg. Porsche which is also all aluminum? Why would these manufacturers want the added complexities?

And further confusing is the all makes/models coolants, that implies there must not be material differences in the blends.

I think the "consensus" on other threads that the modern hoat chemistry GO5 is the "correct" one for our cars. The original green is usually recommended as that was the OEM spec at the time. But my understanding (good luck confirming the trade secret) is the new Prestone All Makes (Green, the colours have no meaning anymore) is in fact a hoat similar to the GO5, so that is proably the lowest cost option that still seems compatible with the cars.

The old green used inorganic acid chemistry, so the newer blends have changed the acids but must still have figured out the metals compatability. The newer blends do all advertise the 5 year life, the old green would be changed out every two years or so. The change in chemistry probably has to do with increasing the fluid change interval for cheaper service while eg. a car is on lease, and perhaps less anitfreeze waste being dumped every two years.