Pentosin CHF 11S vs Full synthetic ATF boiling point?

[V1.47fan]

A lot of VW guys are running full synthetic ATF successfully in lieu of the Pentosin. It seems to me that CHF crap has a lower boiling point and operating temp than a good ATF.

Your thoughts, thanks.

[kawasaki00]

I wouldnt be worried with the fluid as much as compatability with seals and such. ATF like dexron 6 is fantastic fluid, heck even hydraulic cylinders can use the stuff. Just not sure if it is worth the risk though. To me that would be like running DOT 5 fluid. The entire system needs to be cleaned out before it can be used as it is silicone based.

[V1.47fan]

Originally Posted by kawasaki00

I wouldnt be worried with the fluid as much as compatability with seals and such. ATF like dexron 6 is fantastic fluid, heck even hydraulic cylinders can use the stuff. Just not sure if it is worth the risk though. To me that would be like running DOT 5 fluid. The entire system needs to be cleaned out before it can be used as it is silicone based.

At one of the events,The CHF 11S passed its boiling point, causing partial loss of steering and loud growls.
I flushed the the old stuff out and replaced it with full synthetic mobil ATF.

So far so good, no more fluid spills from the vent after back to back runs. From what I've heard of other guys running full synthetic ATF instead of Pentosin, the power steering system is working just fine.

[bigjae1976]

I had a similar issue at an auto-x. I got a p/s growl and the p/s fluid was foamed up. I just let it cool down. Now I just exchange what is in the reservoir every oil change.

I believe the E46 p/s fluid was CHF-11. The E9X is CHF-11S. I guess the difference is the 11s is mineral based? I would be curious to hear if we could use a synthetic ATF like I do in my E46.

[SuckaGDog]

You will make your seals swell and cause pre-mature failure resulting in many leaks by switching a system based on CHF-11S to ATF. If all the components are replaced with new then you might get away with it, but a simple drain and fill, no.

E46s used ATF as their power steering fluid.


Also the filter is built into the power steering reservoir so definitely replace that if you want to switch fluids.

[V1.47fan]

Originally Posted by SuckaGDog

You will make your seals swell and cause pre-mature failure resulting in many leaks by switching a system based on CHF-11S to ATF. If all the components are replaced with new then you might get away with it, but a simple drain and fill, no.

E46s used ATF as their power steering fluid.


Also the filter is built into the power steering reservoir so definitely replace that if you want to switch fluids.

So far so good, many VW/Audi guys switched to full synthetic ATF without causing seals to swell. I think foaming CHF-11S is worst to the ps system.

[bigjae1976]

Originally Posted by V1.47fan

So far so good, many VW/Audi guys switched to full synthetic ATF without causing seals to swell. I think foaming CHF-11S is worst to the ps system.

You have to be really beating down your ps system to get CHF-11S to foam. Auto-x and drifting will do that.

Never had an issue on track once I kept my fluid level near the bottom of the reservoir. I had minimal seepage (if any) and no foaming problems. Never auto-x'd again either.

[V1.47fan]

Originally Posted by bigjae1976

You have to be really beating down your ps system to get CHF-11S to foam. Auto-x and drifting will do that.

Never had an issue on track once I kept my fluid level near the bottom of the reservoir. I had minimal seepage (if any) and no foaming problems. Never auto-x'd again either.

Actually, yes.

It's a two driver car with little time for cool down between runs, and usually pax top 8 out of 100+ cars (SCCA FS class).

[bigjae1976]

Originally Posted by V1.47fan

Actually, yes.

It's a two driver car with little time for cool down between runs, and usually pax top 8 out of 100+ cars (SCCA FS class).

Lol...then I'd try the ATF. With CHF-11S, your ps will fail. With ATF, it might fail.