Coolant Leak frustration (1 Viewer)

[mattressking]

Tightened all the clamps coming from the water pump and pressure tested. No leak at this point! So hopefully that was it. Im shocked that those clamps would have loosened up. is there a better hose clamp?

No, the rubber and metal settles in after it heat cycles. A little adjustment is expected unless using the spring clamps as they adjust tension as rubber shrinks/expands.

 

[NMC_EXP]

Tightened all the clamps coming from the water pump and pressure tested. No leak at this point! So hopefully that was it. Im shocked that those clamps would have loosened up. is there a better hose clamp?

All rubber parts when either compressed or stretched undergo "stress relaxation" and "creep". This amounts to the fact the rubber moves away from a load imposed on it over time. Eventually this stops and equilibrium is reached.

At the same time some "permanent set" is happening. That is you compress rubber and hold it that way for a long enough time, when you release the compression the rubber will not come back to its original dimension (see the permanent marks left in an old hose by the clamps).

Together these two factors could act to reduce the sealing force exerted by a "constant deflection" style hose clamp.

The common worm screw hose clamps are the constant deflection type - you screw then down until it reaches come inside diameter and there is sits no matter what the rubber does.

Other hose clamp styles are the "constant load type". These keep the same load on the hose OD even though the rubber has undergone stress relaxation/creep and has taken a permanent set. A constant load clamp is designed to "take up the slack".

This is all theoretical - I never had occasion to test hose clamps. I did test sealing force retention of other rubber gadgets and it does go down over time in a constant deflection situation.

 

[LandoNick]

This is the style that I have on my hoses. I know witz-end also sells another style

 

[NMC_EXP]

Looks like a constant deflection style clamp.

To me, it makes technical sense that with new hoses you might need to snug up the clamps after some period of time to make up for the changes to the rubber.

 

[Gretsch]

To me, it makes technical sense that with new hoses you might need to snug up the clamps after some period of time to make up for the changes to the rubber.

I have had to do this several times since replacing my cooling system hoses a few years back. Used the same dual hoop clamps from Toyota.

This photo:

Is it me or does that look like oil is getting slung out all over the oil cooler down pipe? I think oil can deteriorate these hoses pretty good which may support the idea of having the hose change over time and needing to tighten the clamp. I could be wrong on that being oil all over the pipe but looks that way to me. Maybe its just dirt wet with coolant. Not sure. Assuming this little hose was changed when the cooling system work was done. Was the timing cover seal replaced when the cooling system work was done? Hopefully the hose tightening will handle it. HTH.

 

[LandoNick]

I have had to do this several times since replacing my cooling system hoses a few years back. Used the same dual hoop clamps from Toyota.

This photo:

View attachment 2457917

Is it me or does that look like oil is getting slung out all over the oil cooler down pipe? I think oil can deteriorate these hoses pretty good which may support the idea of having the hose change over time and needing to tighten the clamp. I could be wrong on that being oil all over the pipe but looks that way to me. Maybe its just dirt wet with coolant. Not sure. Assuming this little hose was changed when the cooling system work was done. Was the timing cover seal replaced when the cooling system work was done? Hopefully the hose tightening will handle it. HTH.

It’s possible there is some oil there. I will clean it off and see if it returns.
No the timing cover gasket was not replaced at that time.
I hear is kind of a nightmare job

just took another 20 minute drive. And dry as a bone now

 

[NMC_EXP]

I think oil can deteriorate these hoses pretty good which may support the idea of having the hose change over time

Rubber types are divided into oil-resistant and non-oil-resistant. In general, the type of commonly used rubber that has the best resistance to coolant and heat is EPDM and it is not oil resistant (enough petro. products and heat will turn it into goo). I do not know what type of rubber Toyota specifies for coolant hose but based on how long they lasted on the FJ40 I bought new they were probably EPDM rubber.

Those two wire clamps may have an advantage over the wide band type clamps. That is the load is spread over a smaller contact area than a band clamp so the PSI sealing force is higher.

 

[Gretsch]

I hear is kind of a nightmare job

Its not for kids, but I did not find it all that big of a deal once I gathered the proper tools. The pulley nut can be a battle but depends on the truck. Mine was no issue luckily. Infinitely easier with Radiator out of the way IMHO. Glad it seems to be fixed.

 

[LandoNick]

Its not for kids, but I did not find it all that big of a deal. The pulley nut can be a battle but depends on the truck. Mine was no issue luckily. Infinitely easier with Radiator out of the way IMHO. Glad it seems to be fixed.

Thank you. Hopefully I won’t be taking the radiator out soon. But if push comes to shove. Thanks for the help always appreciated.

 

[LandoNick]

Rubber types are divided into oil-resistant and non-oil-resistant. In general, the type of commonly used rubber that has the best resistance to coolant and heat is EPDM and it is not oil resistant (enough petro. products and heat will turn it into goo). I do not know what type of rubber Toyota specifies for coolant hose but based on how long they lasted on the FJ40 I bought new they were probably EPDM rubber.

Those two wire clamps may have an advantage over the wide band type clamps. That is the load is spread over a smaller contact area than a band clamp so the PSI sealing force is higher.

I feel with the two wire clamp there is a chance of over tightening and cutting the hose. I’m not that bright though

 

[NMC_EXP]

I feel with the two wire clamp there is a chance of over tightening and cutting the hose.

No doubt that is true. I expect that Toyota has torque specs for those clamps and hoses.

 

[Gretsch]

Just to add to this, here is a nice shot of what can happen to an oil coated cooling system hose:

HTH

 

[NMC_EXP]

here is a nice shot of what can happen to an oil coated cooling system hose:

If it is EPDM rubber and gets oil soaked long enough it will swell up and get very soft. Petroleum products chemically break it down.

 

[Gretsch]

I feel with the two wire clamp there is a chance of over tightening and cutting the hose.

I have found with mine that the clamp either runs out to the end of the screw mechanism or bends long before you could get to the point of cutting through the hose. Thats just been my experience but maybe someone has done it.

 

[dbleon]

I’ve had good luck with these Amazon product ASIN B000CRDL6Q
Screw type always seemed to leak over time and or Bite into and wear out the rubber hoses

 

[MANUCHAO]

I use breeze constant torque clamps on radiator to engine hoses...
No issues

Use the toyota CT wire (posted on previously) clamp on the heater valve hoses..