Silicates & water pump seal life.

[Renners]

Firstly, apologies for another post on the topic of silicates and their potential harm to water pump seals, especially OEM Japanese/asian type.


Does anyone have experience or information on this?

Are the mechanical seals different, are the Japanese using a soft/hard (carbon/ceramic) mechanical seal faces & the Europeans a hard/hard (silicon carbide/tungsten carbide) seal faces, at least industrially hard/hard mechanical seals are specced where abrasive media is expected to be encountered.

Where I work we overhaul (electrically driven) cooling water pumps that run 24/7 at 5 year intervals, most make it without failure, using either nitrite/borate treatment or Radicool SF, these are not silicated, however they are large open systems that are not be free from some abrasive particles.


@Gene K had the below to share, an appreciated post.

“Silicates definitely affect water pump life. A large trucking fleet (thousands of trucks) had water pump failures drop by something like 78% after 1 year of running EC-1 Coolant. After 2 years it dropped to almost none. I used to have to replace water pumps every 200,000-400,000 miles. I have had trucks with over a million miles on the water pumps since EC-1 came out. As a matter of fact since going EC-1 I havnt had to replace a single water pump.”

And @paulo57509 had this interesting Honda information.

FWIW, a copy of this was in with the paperwork I received when I get the Legend. While I don't use Honda branded coolant, I do use a non-silicate coolant.
View attachment 120209

Does anyone have any information or experience to add?

 

[Soft Cars]

It was rumored that silicones in the coolant for a waterpump lube had the potential to clog up radiator cores. One I guy I knew would never use Prestone for that reason. That rumor is about 30 years old though. Maybe coolants have gotten better since then.

 

[brianl703]

It was rumored that silicones in the coolant for a waterpump lube had the potential to clog up radiator cores. One I guy I knew would never use Prestone for that reason. That rumor is about 30 years old though. Maybe coolants have gotten better since then.

From what I found doing a patent search (because, oddly enough, it's impossible to find spec sheets for coolant from 40 years ago on the internet), typical coolant formulas in the 1980s could have as much as 750PPM of silica.

You won't usually find silicated coolant today that has over 250PPM, because one of the heavy-duty specs limits silicates to 250PPM. The lower amounts of silicate should reduce the chances of silicate drop-out.

 

[JohnnyG]

From what I've been told over the years, the issue is not confined to Japanese vehicles. This was a constant warning from a GM engineer back in 1999 or so. He was one of the GM engineers that "designed" (?) the Northstar engine. I have no idea of his exact roll in the process, all I know is that he said he would come to work everyday and a Northstar engine on the test bed was running full throttle for weeks on end.
There were tests being done to use the engine in aircraft at the time!
Anyway, those were the days of Dexcool horror stories and a lot of people were tempted to switch back to "the green stuff".

I think it was the silicates that were abrasive to the water pump seals. Why those seals were different from the ones used for many years prior, I have no idea. Maybe it was just the shaft speeds that were required of the pump in that design.