dexcool + silicone hose

[neo3]

I recently (a couple of months ago) replaced some hoses with silicone versions in an engine that uses dexcool. Now I'm learning that's a bad thing - the dex has 2-eha that will eat the silicone? Does this apply to any type of silicone hose? The hose I used has two layers, the inner is red, the outer is blue, if that means anything. I guess I'll need to flush the coolant and pick a non-2-eha type?

 

[Jimzz]

I heard about that many years ago but never could find anyone that had an issue. Could be hoses have a different type of silicone and/or the type that had issues had been discontinued for a while.

 

[DBMaster]

This is a page from a manufacturer of hoses. I've copy/pasted the relevant sentence below.

https://shorehoses.com/selecting-hoses-for-different-oat-coolants/


Organic Acid Based Coolants which contain Ethlyhexanoic acids, are incompatible with Silicone Hoses. EHA/EHA acids gradually soften the silicone hoses (even if they are lined with Fluorosilicone) and cause them to ultimately burst.

 

[neo3]

Originally Posted by DBMaster
This is a page from a manufacturer of hoses. I've copy/pasted the relevant sentence below.

https://shorehoses.com/selecting-hoses-for-different-oat-coolants/


Organic Acid Based Coolants which contain Ethlyhexanoic acids, are incompatible with Silicone Hoses. EHA/EHA acids gradually soften the silicone hoses (even if they are lined with Fluorosilicone) and cause them to ultimately burst.


Thanks, I guess I will be changing coolant.

 

[DBMaster]

Originally Posted by neo3
Originally Posted by DBMaster
This is a page from a manufacturer of hoses. I've copy/pasted the relevant sentence below.

https://shorehoses.com/selecting-hoses-for-different-oat-coolants/


Organic Acid Based Coolants which contain Ethlyhexanoic acids, are incompatible with Silicone Hoses. EHA/EHA acids gradually soften the silicone hoses (even if they are lined with Fluorosilicone) and cause them to ultimately burst.


Thanks, I guess I will be changing coolant.


I would have never guessed that myself. I thought silicone hoses were impervious to everything. Thank you for the opportunity to learn this while doing a search based upon your original question.

 

[Jake_J]

I would say ditch the racer blue silicone hoses instead of changing the coolant. The Shore guide is kind of muddled since they refer to OAT coolants containing 2-EHA being potentially harmful to silicone yet they state "Silicone Hoses might not work for some OAT or hybrid-OAT coolants, even if EHAs are absent".It's generally believed that Asian vehicles use OAT coolants with Sebatic Acid which is also a plasticizer so those would also be incompatible with these silicone hoses. Considering that all vehicles made in the last 15-20 years use OAT or HOAT coolant I would say go back to the stock EPDM hoses or flush the coolant and switch to old school green (IAT) (against your manufacturer's recommendation).

 

[neo3]

Well changing the hoses would be way more of a PITA than changing the coolant. I used small diameter hoses + an fittings to replace original small diameter metal piping (runs under the intake) that was a problem, it's not the main radiator hoses. I used silicone just due to it's high heat tolerance, and it runs in back where you can't see it or reach it. Don't care at all how it looks. I'm changing to Zerex G-05, looked at the SDS it seems OK, but interested in any counter argument. Thanks.

 

[clinebarger]

The 1996 9C1 Caprice came from the factory with silicone hoses & Dexcool, Most went to the scrap yard with the original hoses. We backspecced a bunch of 94/95 9C1's with Dexcool without issue.

Also did a lot of silicone hose swaps on Impala SS's using 9C1 hoses, Probably got the whole rumor mill going that the SS came with silicone hoses which they didn't.

 

[FCD]

I was using an OAT coolant ( G12++ ) which uses Sebacic acid instead of 2-Eha but still, on my 1988 Escort, the upper radiator hose started weeping being less than 1 years old, and the heater core also had a small weep so when you turned on the heater you got a pretty strong smell of coolant, then i switched back to conventional coolant ( Motul G11 Blue which meets the original Ford M-97B49-A spec ) and the weeping stopped immediately, heater stopped weeping and doesn't smell anymore.