Silicone heater hoses

N2BRK

Well-known member
Dec 31, 2009
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I'm wondering how much success or lack thereof folks have had with these. When it was time to do mine, I bought silicone instead of GM and I have had nothing but leak after leak. I have tightened and re-tightened many times. Some days or weeks or even months I'm ok and then a season will change or something and it's like Valdez under my truck. Last winter I had a small leak that I couldn't stop, so I was relieving pressure when I'd get home each time. Then it stopped when the weather got warmer. This morning there's a flood under the truck from another spot. Is this dumb luck or were these a bad idea?

TIA for feedback.

Wally
 

Bdsankey

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Feb 1, 2018
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What hoses are you referring to? Are you positive its coming from the hoses? If so, might be a good idea to replace them. I'm going to assume you're talking about the large diameter radiator plumbing. My ACDelco is going strong after 3 seasons of beating it and was cheap.
 

N2BRK

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Dec 31, 2009
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these:
 

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DAVe3283

Heavy & Slow
Sep 3, 2009
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Boise, ID, USA
Silicone hoses are generally not recommended for street / DD applications. Most people seem to have your problems with them, where the clamps need tightened constantly or they leak. I have read that silicone hoses are actually somewhat permeable by water, so you slowly lose water from your system (not like a puddle, tiny bits come through and flash off). That means your coolant mixture gradually becomes more and more glycol unless you top off with only water.

I run a set of silicone hoses on one of my dirt bikes (they are colored to fit the theme of the bike), and they have worked well, but I probably put 500 miles/year on that bike, and I check the clamps frequently. I have avoided them on my cars/trucks because of the high maintenance.

Yours sound worse than "normal" for silicone hoses, but if you are looking to have a more maintenance free truck, you will want to look into spring clamps (like stock, but I'd get more tension) instead of the T-bolt clamps. The T-bolt clamps don't compensate for thermal expansion in changing weather like a spring clamp does. Or do like me, and stick with plain rubber hoses. Not as sexy, but they just work.
 

1TRIKHD

Country boy Limo.
Sep 15, 2015
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P.N.W
Well shit, i have the same kit, but I haven't put them on yet. Hopefully I dont have the same issues as you are having.
 

N2BRK

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Dec 31, 2009
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That's a really fair answer. I jumped on these because I thought that they were an improvement over stock, and I was in need of replacing mine. It looks like I made a mistake and these aren't for me. I hate doing a job (and paying for parts) twice!! Thanks
 

N2BRK

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Dec 31, 2009
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asked me if the clamps were maxed out yet and if not, keep tightening. I have them so tight that it scares me to go more... yes there's some left on them - but I'm worried about deformation they are already so tight.
 

1TRIKHD

Country boy Limo.
Sep 15, 2015
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P.N.W
asked me if the clamps were maxed out yet and if not, keep tightening. I have them so tight that it scares me to go more... yes there's some left on them - but I'm worried about deformation they are already so tight.

You wouldnt think you would have to max out the clamps to keep it from leaking. Jesus!
 

THEFERMANATOR

LEGALLY INSANE
Feb 16, 2009
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I run silicone hoses on my heater core lines(not PPE's or MISHIMOTOS, bulk hose I got locally). GM used silicone from the factory on the heater hoses on 6.5 SUB's because of how close they ran to the engine. I used the stock spring clamps and have never noticed and coolant drips or leaks, but I do ALWAYS have a coolant smell around them, and I do lose a little bit of coolant every oil change.
 

Burn Down

Hotrodder
Sep 14, 2008
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Boise Idaho
You need a constant tension spring clamp, you can get them in a t-bolt style or worm clamp. Don’t over tighten them, some silicone is soft enough that the clamp can actually cut through it. We used silicone hose all over cat equipment, with no coolant leaks...
 

N2BRK

Well-known member
Dec 31, 2009
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ok, so maybe I'll try new OEM spring clamps on the leaky connections first before ripping them out. Thanks
 

N2BRK

Well-known member
Dec 31, 2009
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I’m also going to give PPE another holler to see if they have anything to add. I’m trying to add pics but keeps failing. Odd.