Does anyone here have experience with coolant filters?

In the Jag V12 world, many people use Tefba filters in the upper radiator hoses to keep the radiator and block clean.

I'd like to order one to fit the Porsche but as I'm in Africa and my Porsche is in the US, I can't easily measure the ID of the upper radiator hose.

 

not needed, just flush or replace radiator. Why would you need a filter, just one more thing to worry about.

 

If there is debris in the block, stopping it getting into the radiator tubes might be useful, but you cant rely on the water only going in one direction - filling the radiator will flush debris on the block side of a filter back into the block.....And eventually all filters clog up. Nobody has all the wisdom, but are Jag V12 owners more rational than sharkers?

jp 83 Euro S AT 56k

 

The 928 offers the ability to flush crud out of the bottom of the coolant galleys in the block, something few other production cars bother with. I'm sure others will chime in about how the lower sections seem to gather crud, to the point where several guest cars have needed some serious probing in the plug bosses to free up stuff that had gathered there. Having a filter probably wouldn't prevent that accumulation. Plus you want to pull those plugs to get the old coolant out anyway.

Regular coolant changes no more than two years apart, using a correct coolant and distilled water, means that there's no accumulation in the galleys on my car between changes. Consider regular service as an alternative to needing a crud filter.

 

What are you putting into the coolant system that would require a filter anyway?

 

Big trucks (semi trucks) run them.

But (and it's an important "but") they never change coolant. Anytime the radiator gets drained, they save it & dump it back in. Disposing of old coolant on that sort of scale gets very expensive.

The filters contain an "additive capsule" that replaces all the additives that wear out or break down over time. That's actually a more important part of the filter than the "filtering" part.

Proper "flush & change" intervals ensure that the coolant stays "fresh" and remove the need for the filter and it's additives.

 

The popularity of the coolant filters in the Jag V12 world stems from the tendency of the engine to drop valve seats in the left bank when overheated. The fact that the Jag radiator requires the left bank to make two passes through the radiator makes overheating issues more common.

Coolant filters are not just for big rigs. Just for grins, check out the number of them available on Amazon.

The bible about this is Kirby Palm's XJS book. There is a very long section on cooling issues. The issue arises with aluminum blocks/radiators and the fact that ethylene glycol is continually breaking down to oxalic acid, which attacks the aluminum. Further, any air bubbles in the system introduces oxygen into the mix, which further accelerates corrosion potential. Here is a small excerpt from the book:
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Scott Fisher sends the following wisdom: “In the context of the automotive cooling system ethylene glycol is not an anti-corrosive agent; it is in fact corrosive. To offset this fact, manufacturers add anti-corrosives (inhibitors) to the glycol. These preparations, while in good condition, perform well in both minimizing corrosion and preventing freezing of the coolant. However, over the life of the coolant the anti-corrosion properties of the inhibitors are depleted.

“Water aids corrosion in three main ways:
1) bringing free oxygen in close contact with the metals so that corrosion
(oxidation) can occur.
2) Water is conductive. Once water has been flowing in your cooling system for some time, its conductivity will rise as it picks up metal ions. The water may serve to promote electrical activity which may erode
metals by galvanic action.
3) Some of the metal ions in the water may also react directly with the metal surfaces.

“Apart from supporting the above three processes, ethylene glycol has the added unfortunate property that it oxidizes through several stages to oxalic acid. The products of ethylene glycol oxidation by oxygen and subsequent reactions include: aldehydes, carboxylic acid, nitric acid, glycolic acid, glyoxylic acid, oxalic acid, formaldehyde and formic acid.

Most of the series of oxidation products to and including oxalic acid are directly corrosive to metals. Added to this, oxalic acid is highly toxic.

“To combat the above acids and other corrosion activity, antioxidants and alkaline formulations are added to the glycol mix. These include many compounds which are used in cooling systems where antifreeze properties are not required and include primary, secondary and tertiary amines; organic and inorganic phosphates, silicates cresols and other phenolic substances; a wide variety of sulfur compounds; soaps; alkali metal salts; and borates.

“These inhibitors slow down the corrosion process caused by the glycol and the water. They may coat the metal surfaces and prevent corrosion by passivation. Passivation is the process where the a protective film forms on the metal
which prevents further contact with the solution. Unfortunately, in all coolant preparations (with or without glycol) the inhibitor system (during engine operation) is being continuously depleted in the performance of these actions. For this reason, proper cooling system maintenance is critical.

“One aspect of cooling system maintenance that we can all easily follow is to minimize “aeration” of your coolant. Aerating accelerates the uptake of free oxygen from the atmosphere. As free oxygen is one of the essential ingredients
for corrosion, the importance of minimizing it’s uptake is clear. To this end you should make sure all your hoses are in good condition and clamped tightly. “Closed systems”, where an expansion tank and recovery system closed to the
atmosphere is used, also help in this regard.

“If you overheat (boil) glycol-based coolants they must be replaced immediately as this accelerates the oxidization process of the glycol to acids.”

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Joe: you're right about the filters in big rigs being more important in replacing additives than in filtering. However, having taken apart some filter elements and seeing the crud they capture, they do perform an important filtering function. I use them on my diesel land cruiser here in Uganda, as cooling is paramount here.

The Tefba filters are available in clear plastic, which aids in allowing one to see if there is aeration present in the coolant.

From what I have learned from my Jag experience is that the filters do help in keeping the radiators cleaner from not having any corrosive-related crud blocking them up, and from allowing one to actually see aeration in the coolant mixture.

That's basically why I was wondering if they were also common in the 928 world.