RTV gasket maker inside hoses?

Zac Owner/Technician Maine Posted   Latest   Edited  
Discussion
HVAC
2013 Dodge Dart Limited 2.0L (A ECK) 6-spd (6F24)
Vehicle Overheating

I recently installed a thermostat assembly in a dodge dart. The vehicle had been to a few local shops and each shop had their own separate diagnosis. The last shop that the vehicle had been to determined that the hoses were leaking past the spring clamps. The replaced some of the spring clamps with screw type hose clamps. The locations where they replaced the clamps they also applied black RTV sealant inside and around the neck of the hoses. I have never seen or heard of this being done before. And I would be apprehensive to do this myself as I would be concerned that pieces of dried RTV sealant could easily be introduced into the cooling system and cause many more problems as a result. The other few shops refused to replace the thermostat assembly citing the task as "too difficult to be worth it" according to the customer which as far as I'm concerned was the underlying issue of the vehicle overheating in the first place! replacing the thermostat assembly did fix the overheating issue. So I'm wondering if this is now standard procedure with stubborn "leaking" hoses to apply rtv inside of the hoses?

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Dan Owner/Technician
British Columbia
Dan Default
 

“Too difficult to be worth it” is a garbage statement. Those difficult jobs is why we do what we do. As for rtv on the hoses, I wouldn’t do it. That’s for people who are not confident that they can do the repair properly.

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Bill Technical Support Specialist
Arizona
Bill Default
 

I saw this from time to time over the years. I personally think it is a bad idea for two reasons. One, the older types or RTV had copious amounts of acetic acid in them and it seems like use in that application always seems to be coupled with extreme corrosion of the thermostat neck which often times is a "pot" metal. If one were to use something like RightStuff (low acid content), one would…

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Zac Owner/Technician
Maine
Zac Default
 

Yeah I've heard of something being "too difficult to be worth it". Especially when it is in regards to the underlying issue of a vehicle overheating. So I'd have to assume that their alternative would be to drive it until the block cracks? My stance with repairs has largely been that if something is supposed to be there then that's how it would have come from the factory. And as I mentioned they…

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Rudy Technician
California
Rudy Default
 

If a hose is leaking, the clamp is bad, hose is bad, or the assembly it attaches to is bad, Period. There are no stubborn leaking hoses. Applying RTV is a hacks choice, similar to those that apply RTV to metal water pump gaskets or rubber oil pan gaskets. Really chaps my hide when I have to do a job behind one of those guys!!!

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Roy Mechanic
Manitoba
Roy Default
 

Amen to that. FWIW, Our shop policy is.. if a tech works on a vehicle and removes any of those spring clamps, they are replaced with new gear clamps. Spring clamps are designed for ease of factory assembly and can leak when re-used. At the low cost of decent hose clamps, it is good insurance against a roadside problem and comeback.

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Marlin Technician
Oregon
Marlin Default
 

Spring clamps provide more reliable sealing than standard gear clamps. If a hose is removed and installed, and the clamp is not severely degraded by rust or abuse, assembly with the old clamp in its original position is more reliable than replacing it with a different type. "In its original position" is the key.

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Roy Mechanic
Manitoba
Roy Default
   

We use good stainless clamps similar to those used for marine thruhulls. (Typical ones are only partially stainless and have the thread grooves all the way around ) Our shop is owned by someone who worked in a rad shop for decades. Nothing but cooling and ac. Day after day. And they never had combacks due to clamp failure if they always replaced them. Same goes for us, unless a new tech doesn't…

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Marlin Technician
Oregon
Marlin Default
   

Quality and material of the clamps definitely is very important. We only use Ideal, 57 series for the larger sizes (stainless except the screw). We torque to spec. They work very well, but they still are not as … as (…) constant tension designs. There are cases when the original hose and clamp will not seal, but either the clamp is damaged or the hose really needs to be replaced.

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Chris Technical Support Specialist
New York
Chris Default
 

Also spring clamps provide constant tension. As the rubber expands and contracts over time and temperature the spring clamp will adjust as to a worm/screw clamp will remain the same diameter. Spring clamps when not damaged and reinstalled in the original depression in an existing hose will typically do their job better than a screw clamp. How many people actually torque their screw clamps??? The…

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Bill Technical Support Specialist
Arizona
Bill Default
 

I used to work in the bay next to a guy who had allergies to those clamps. I saved them all and still have a hundred or more in a complete variety of sizes that I use on my own personal vehicles. I also use the Oetiker style clamps. Beevo

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Roy Mechanic
Manitoba
Roy Default
 

Thats the issue i have with them. Often with newer vehicles it is harder to get the clamp in the same spot if the clamp is relatively inaccessible. With a gear clamp you can position it where you need and simply tighten it to solve a leak from an older hose that a customer won't want replaced. While from an engineering standpoint, the spring clamps can expand and contract, in application i…

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Rudy Technician
California
Rudy Default
 

Roy- I cant speak for the other guys, but we use screw clamps. There may be truth to the superiority of spring clamps, but screw clamps absolutely work, and work very well. Personally, Im not going to try to find the same depression in a hose buried in the back of the block or under a manifold, when I can use a new screw clamp and be done with it. No need to over think this.

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Marlin Technician
Oregon
Marlin Default
 

It is not and should not be standard practice, but some just do it. Torquing the clamps correctly is what really needs to be done. There is a place for gasket maker, when the neck is badly pitted and replacement is not viable. I have done it many time with … results. The neck needs to be cleaned very well first. I pity the next person who works on it, but most of them have one foot in the…

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Jan Owner/Technician
Ohio
Jan Default
 

I agree with Marlin Good. He has a good response for the situation as he stated.( bad neck and or pitted, when a good neck is not available)

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Zac Owner/Technician
Maine
Zac Default
 

I could certainly see it being done in a situation as a last resort when all other means of a proper repair have been exhausted. But on a 2013 with only 60k miles and not a speck of rust or corrosion present anywhere on the vehicle it doesn't make sense. And they only applied this "repair" in conjunction with aftermarket clamps to the hoses that were most easily accessible. To my understanding…

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Darren Technician
Oklahoma
Darren Default
 

I have used rtv on deep pitted nipples and gasket sealing surfaces when the customer was not willing to replace a part , including timing covers and intakes. Do not use it with a cork gasket. The cork will squeeze out. Sometimes even when the cork is glued to the other piece. if there is minor pitting , scratches on hose sealing surface or rubber gaskets or oring surfaces, I use Teflon paste…

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