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Thread: OBX silicone radiator hoses.

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2012-02-19 17:46:38
OBX silicone radiator hoses.
Copied from my build thread: https://www.sr20-forum.com/members-rides/!519-benfenners-1994-black-se-r.html?post_id=723591#post!723591

Silicone radiator hose installation

First, let me say this is a bad idea. I regret this installation and I will be going back to rubber ASAP.

So here's the story. My passenger side main radiator hose got a tear in it (mainly due to age, but my charge piping also puts some stress on it as they are configured currently) so I needed to replace it. Both hoses are quite old so I called up Greg for some replacements. Greg told me he had silicone radiator hoses (in black) and that they were comparably priced to OEM stuff and could be shipped out right away (instead of having to be ordered). So I figured why not? I like upgrading when ever I have the opportunity.

It wasn't until later that a couple things on MotoIQ popped up that just so happen to discuss silicone hoses. There are two articles (don't forget to read the comments) that I can find right now.
1) Wrench Tips #24 - Silicone Hoses for Adults > MotoIQ
2) Silicone Radiator Hoses: Not for the Street > MotoIQ

They mention that silicone is really not to be used for liquids (fuel, coolant, etc.) because it is porous. Additionally, it expands and contracts with temperature changes much more than rubber making the hose clamps ineffective at sealing. Doing more research I found that apparently silicone radiator hoses were all the rage for the trucking industry for a short while until everyone figured out they leak like clockwork over the cold nights of winter. For a while people started using self-tightening clamps, spring loaded clamps, and other methods to try and fix the problem but nothing really worked. Everyone in the industry went back to rubber.

Even so, I was hopeful that I could maybe avoid the problem or minimize it somehow. I had a leaking hose and I had these new ones and they would just have to do. At the least I'd get to corroborate the results if/when they leaked.

Spoiler alert: they leak.

I wasn't too excited about the brand I received either.

Let's get started.

Without any cutting this is how things looked. These hoses are cut-to-fit. They are much too big. I don't think that is on purpose. O_o

One nice thing about them being too long means that I can customize them to route around my 3" intake pipe as best as possible.

Measure 40 times, cut twice per side. That's how the saying goes, right?

They look and fit great. Too bad they leak.

I really need to do something about that rust under the radiator support.

This one is a bit crazy. It doesn't look like it will work by the shape of it, but it ends up working fine. Also, OBX likely knows all about the silicone leaking problem with temp changes. Because of this, they've slightly undersized their hoses to create an extremely tight fit. The problem with that means this hose (being smaller and less flexible than the big hose) is almost impossible to mount on the radiator and engine block.

No cutting done yet.

Notice I've scraped off the OBX logo. I did that one both hoses. Screw you OBX.

I think I cut some of the hose. Maybe I didn't? I don't have any pics of it anyway. I ended up having to use the dish soap as lubricant to get the freakin' hose to mount up on the bungs. I feel sorry for any 120 lb. women who attempt their own car work. I don't see how they could do it.

Charge pipes hooked back up.

That's my story and I'm sticking to it.

I'll post pictures of the leaks when I get around to it. All four ends have slow leaks when the car is just sitting in the garage.
Last edited by BenFenner on 2020-06-24 at 11-01-49.
2012-02-22 16:22:46
Thread approved.

Thanks for the review, I'll keep away
2012-02-22 18:09:35
Alot of guys run these silicone hoses including me. I haven't had any problems yet. I can't really see the hose expanding and contracting that much with heat. I mean once you clamp it down it can expand or contract that much. Who knows though

Anything is better then the rubber hoses that crack at the exact wrong times!
2012-02-23 01:08:49
FYI. Also from MotoIQ

After reading the following information as well as the other links BenFenner posted, I'm thinking the leaking might be more a result of inferior products rather than a complete blasting of silicone radiator hoses.

Wrench Tips #24 - Silicone Hoses for Adults > MotoIQ

Originally Posted by 8695Beaters

Monday, August 29, 2011 5:46 AM

I wonder if this stuff will help prevent silicone hoses from leaking so much. I'll have to try this out, I have mostly stock rad hoses in my car, but one bright blue hose smack in the middle. Not for long!

Originally Posted by Dave

Monday, August 29, 2011 6:53 AM

If your silicone hoses are leaking now, I doubt more silicone will solve the problem. Is this problem something you have personal experience with, or have you been reading propaganda from rubber hose companies? I've never had any silicone hose leakage issues myself.

Originally Posted by Mike

Monday, August 29, 2011 8:57 AM
Silicone hoses breath some and you can usually smell coolant but they don"t actually leak.

I carry a roll of this stuff in my race support backpack.
2012-02-23 01:32:08
yeah i run em too, havent had a problem.

2012-02-23 01:38:26
I wish I knew where that link was about the truckers...
2012-02-23 01:39:15
i dont care about no stinkin link , ;p.

like i said ive ran silicon hoses on alot of my cars, not one issue.

2012-02-23 01:58:25
Maybe you guys in warm climates don't have issues? The main problem is the hoses shrinking in thickness over cold nights which now makes the clamps too big, if you follow me, so they are no longer tight on the bungs. And you get seepage.

I don't know how much more sexual I can make this explanation...
2012-02-23 02:11:48
Originally Posted by BenFenner
Maybe you guys in warm climates don't have issues? The main problem is the hoses shrinking in thickness over cold nights which now makes the clamps too big, if you follow me, so they are no longer tight on the bungs. And you get seepage.

I don't know how much more sexual I can make this explanation...

2012-02-23 22:32:14
Ben youlive down the street pretty much you perv! You live in a warm climate its 80dg today in feb....anyway it just sounds like from reading that you need to let the car warm up and retighten Them. My se-r has been running siliclne for over two year with no leaks
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