New upper radiator hose leak

[Sahara01]

I recently did a coolant flush and replaced the thermostat and radiator hoses. Other than fighting one of the lower radiator hose clamps for way to long the job went smoothly. Drove the jeep several times over a week and no leaks.
I did this work, oil change and diff fluid change before taking it on a longer trip up to the mountains, Yosemite and the eastern sierras.
Well the second morning I took a short drive and notice something leaking. Popped the hood and it was coolant coming from either the upper rad hose or t stat housing. Took it back to camp cleaned it up torqued the t stat bolts and adjusted the clamp. I figured I screwed up the gasket but I was able to pinpoint the leak to the top radiator hose. I had a hard time getting the hose clamp in the perfect position because it seems to hit the valve cover. But once the engine was hot the hose would either swell enough to stop leaking or the coolant would evaporate on the hot t stat housing. I continued to check on it throughout the trip. No more coolant hitting the ground the entire time.
Any suggestions on how to get that darn clamp position right or a different clamp? I may even return or exchange the hose.
I am wondering if the colder weather had something to do with it or perhaps some of the trails I took knocked the hose clamp loose.
Oh and while I stopped at one of the view points some ding dong backed into my jeep. I saw it as it was happening and tried to yell across the road. Saw the jeep move a little bit and I cringed. It wasn't like it was a tight parallel parking spot, there was plenty of room. I was pretty hot to say the least. But I couldn't find any damage.

 

[Kiwi TJ]

What hose clamp are you using? The ones you open with pliers or the screw in ones ?
When I swapped out my cooling system I changed mine out with the screw in ones and very easy to tighten/loosen near the valve cover (never had any issues and they don't seem to cut into the rubber too much either)
As for the ding, there was probably more damage to his car than the Jeep.

 

[Sahara01]

I'm using the spring tension style you open with pliers. Maybe that one has just worn out. Only other thing I can think of is that the end of the hose seemed to be cut at a slight angle. Thing that gets me is it didn't leak at all for a week.

 

[Kiwi TJ]

I'm using the spring tension style you open with pliers. Maybe that one has just worn out. Only other thing I can think of is that the end of the hose seemed to be cut at a slight angle. Thing that gets me is it didn't leak at all for a week.

On your long journey and if its not fitting properly it may have worked loose...plus at a guess if you were hitting hills and fully laden your TJ would have been working hard.

 

[mrblaine]

What hose clamp are you using? The ones you open with pliers or the screw in ones ?
When I swapped out my cooling system I changed mine out with the screw in ones and very easy to tighten/loosen near the valve cover (never had any issues and they don't seem to cut into the rubber too much either)
As for the ding, there was probably more damage to his car than the Jeep.

The constant tension clamps are better. Far better.

 

[Kiwi TJ]

The constant tension clamps are better. Far better.

Are those the ones you have to use pliers on ? I had issues with them cutting into the rubber, hence the change and came recommended by the radiator specialist, but fair enough. lol

 

[mrblaine]

Are those the ones you have to use pliers on ? I had issues with them cutting into the rubber, hence the change and came recommended by the radiator specialist, but fair enough. lol

The only reason they would cut into the hose is if the wrong size was in use. I've worked on more TJ radiators than should be legal and I never use a worm drive clamp. The reason is as the necks warm up and the rubber warms up, they swell and expand. That eventually leads to the rubber being over compressed and a potential leak spot. Constant tension clamps are just that, they provide constant tension no matter what the hose and neck are doing.

The common issue is the neck has corrosion and isn't clean which can be fixed and then there will be no leaks. It is common to work on an older system and remove a hose and not get the clamp back into the same place it was which can cause some seeping. If the clamp is repositioned back to it's home, it will usually stop the seep.

 

[Sahara01]

Just an update. I adjusted the clamp one last time before going with a new hose and it seems to have stopped leaking. Odd but happy it's not leaking anymore.

 

[Jerry Bransford]

Are those the ones you have to use pliers on ? I had issues with them cutting into the rubber, hence the change and came recommended by the radiator specialist, but fair enough. lol

That constant tension hose clamp is by far the best type to use and it's also the type installed onto all new vehicles. The factory does not use those cheap worm-gear type hose clamps there.

The benefit to the constant-tension style hose clamp is that it self-adjusts for the constantly varying temperatures at the hoses. The tension is always correct no matter what the temperature is. I stopped getting seasonal/temperature based leaks once I converted back to the OE style constant tension clamp.

 

[Kiwi TJ]

That constant tension hose clamp is by far the best type to use and it's also the type installed onto all new vehicles. The factory does not use those cheap worm-gear type hose clamps there.

The benefit to the constant-tension style hose clamp is that it self-adjusts for the constantly varying temperatures at the hoses. The tension is always correct no matter what the temperature is. I stopped getting seasonal/temperature based leaks once I converted back to the OE style constant tension clamp.

Sounds like I'll be swapping mine out then before Summer really kicks in ..

 

[khakitj]

... I figured I screwed up the gasket but I was able to pinpoint the leak to the top radiator hose. I had a hard time getting the hose clamp in the perfect position because it seems to hit the valve cover. But once the engine was hot the hose would either swell enough to stop leaking or the coolant would evaporate on the hot t stat housing. I continued to check on it throughout the trip. No more coolant hitting the ground the entire time.
Any suggestions on how to get that darn clamp position right or a different clamp? I may even return or exchange the hose.
I am wondering if the colder weather had something to do with it or perhaps some of the trails I took knocked the hose clamp loose.

im having the same issue right now. how did you adjust the clamp to get it to stop leaking? my guess is the clamp doesn’t actually need to be so far down the neck that it hits the valve cover.

 

[strichzwei]

I had the exact same issue!

I think my problem may have been a combination of different things, I observed:

1) I feel the valve cover doesn't allow the spring tension clamp to go on low enough! mine is just barely below the lip on the T-stat housing but is now working.

2) I had a brand new Mopar (!) T-stat housing and the casting/finishing on it is absolutely horrible, there are actual ridges (witness lines) where the die-cast tooling separates, I had dress these with a file somewhat.

3) the continental hose I purchased was a bit longer than the original and ultimately the new mopar hose I ordered while fighting this leak and I think it put undo pressure at the T-stat housing junction (although not really sure this had an impact....guess I could have shortened it as well).

4) I was using an original spring tension clamp at the T-stat housing and noticed it was slightly larger diameter than the new one I ordered (maybe it did not offer as much clamping pressure anymore...).

Mine now does not leak (knock on wood), if it does I will resort to a worm gear clamp at the T-stat housing so that I can secure it lower down on the hose).

Scott

 

[khakitj]

I had the exact same issue!

I think my problem may have been a combination of different things, I observed:

1) I feel the valve cover doesn't allow the spring tension clamp to go on low enough! mine is just barely below the lip on the T-stat housing but is now working.

2) I had a brand new Mopar (!) T-stat housing and the casting/finishing on it is absolutely horrible, there are actual ridges (witness lines) where the die-cast tooling separates, I had dress these with a file somewhat.

3) the continental hose I purchased was a bit longer than the original and ultimately the new mopar hose I ordered while fighting this leak and I think it put undo pressure at the T-stat housing junction (although not really sure this had an impact....guess I could have shortened it as well).

4) I was using an original spring tension clamp at the T-stat housing and noticed it was slightly larger diameter than the new one I ordered (maybe it did not offer as much clamping pressure anymore...).

Mine now does not leak (knock on wood), if it does I will resort to a worm gear clamp at the T-stat housing so that I can secure it lower down on the hose).

Scott

I was just remembering this project because I was reading and watching videos about the ClampTite tool, and I was thinking that if I had it at the time I probably would have used it here. Fortunately mine hasn’t leaked since I posted that message above.

I too noticed that the hose I purchased was longer than the original. I shortened the hose and then the section I was clamping had a smaller O.D. that made it possible for the clamp to fit where the valve cover had been touching.

 

[Wajeep]

I did the same thing as you and struggled to get the constant tension hose clamp where it needs to be connecting the lower radiator hose to the water pump housing. I opted for the worm clamp hose clamp in that spot. It was so much easier to get on tighten and stop the little itty bitty leak that was there.

 

[AndyG]

That constant tension hose clamp is by far the best type to use and it's also the type installed onto all new vehicles.

I had zero clue, makes total sense after reading yours and Blaine’s posts.

Ignorance isnt bliss, it’s just ignorance.

 

[Jerry Bransford]

I had zero clue, makes total sense after reading yours and Blaine’s posts.

Ignorance isnt bliss, it’s just ignorance.

Blaine is who clued me in on that years ago. I commented to him I was getting seasonal hose leaks after redoing my cooling system. His reply was something like 'You used those fucking stupid adjustable hose clamps didn't you!'

 

[AndyG]

Blaine is who clued me in on that years ago. I commented to him I was getting seasonal hose leaks after redoing my cooling system. His reply was something like 'You used those fucking stupid adjustable hose clamps didn't you!'

Blaine can make a point ....sometimes it’s hard to take but refreshing to see someone call bull on things like he does. He thinks conceptually very well.

I hope other forums work for members like this one does. That is valuable knowledge about the clamp. Make it home /not cook the 4.0 valuable.