Coolant Leak Mystery

[Brian McVickers]

Hi all,
Looking for some insight:

Last fall my 2001 DII developed a subtle leak from one of the coolant hoses.
This was addressed by installing all new coolant hoses and a new T-stat.
Regardless, there was always a bit of a drip, or seep, from one of the hoses and then another. Never a gushing leak though.

Then, around December, the heater core blew out. This was fixed with a new heater core.

Now I am noticing seeps and drips from the coolant expansion tank, probably from the seam of the plastic bottle, a common place to have leak on such bottles; or possibly the bottom hose connection.

So - my question is if there is some underlying issue with the cooling system and its pressure?

The engine does not overheat and remains consistent at the halfway point on the temp indicator. This leak in the system just seems to wander from one hose connection to another. I'll reseat a hose and or just tighten the hose clamp and the leak goes away but eventually appears at another connections within the system.

Could all the hose clamps be too loose or maybe just bad clamps?

I have read some about pressure testing the system but that is usually done just to try and find the leak, correct?

Could there be a blockage in the radiator? Although there is no overheating issue, just this pesky leak.

Thoughts???

Thanks
Brian

 

[Grim Reaper]

As coolant ages it becomes acidic and uses up the chemicals that are in it to protect the cooling system. It will go from protecting the system to eating the system.

It is recommended to be changed ever 2 years if you are not using one of these extended range 5 year rated coolants (and the jury is still out on them).

Has the truck been getting regular changes?

http://bioengr.ag.utk.edu/Extension/ExtProg/machinery/Articles/engcool.htm

 

[Brian McVickers]

The last complete coolant flush was about 20K miles ago with a partial, probably 50% coolant replacement when I switched out all the hoses.

 

[madizell]

You can have the radiator cap pressure tested. It may be failing to relieve pressure at its preset value, which would cause unusually high pressures in the system. You may also have the wrong cap with too high a rating. Worth checking out.

 

[Brian McVickers]

Thanks,
Good call on the rad cap.
Interesting thing about the DII is that there is no rad cap on the rad but ther is a fancy cap on the expansion tank along with an overflow breather tube.
The system is pressurized at about 15psi.

 

[MuddyMudskipper]

Thanks,
Good call on the rad cap.
Interesting thing about the DII is that there is no rad cap on the rad but ther is a fancy cap on the expansion tank along with an overflow breather tube.

It is the same for the RRC, DI, and Defender.

 

[RonL]

My wife's upper rad hose at the t-stat leaks a couple of drops even time the weather turns cold. I replaced the hose and clean the T-stat neck and new hose clamp and it still leak a couple of drops. I never see coolant but do see the discolorazation. Maybe the cast Alum T-stat neck is cause this problem.
If the Rad cap was not working right you could blow a hose in the summer.

Step you can do.
1. Flush out old anti-f and replace with new.
2. Replace overfull tank cap
3. Replace all hose you have not replace yet.

It may some like you are replace things that done need it, but if your hose blows or you lose coolant and you cook the motor, it will be $2000 to $8000 to fit that.

 

[yubert]

You might also want to check the throttle body gasket. The original design was prone to create a subtle leak that was hard to see under all the hoses but you could smell it, LR designed a new throttle body housing and gasket to fix this. I think the part is around $25.

 

[madizell]

Here's an old school suggestion: Find the leaking joint, disassemble, clean thoroughly both the hard part and the inside of the hose that leaks, apply some Aviation Form-A-Gasket No. 2 to the parts to be joined, and clamp them back together. The goop fill small gaps and scratches that perhaps the rubber can't track, and does not make so much of a mess that it can't be disassembled when needed.

Also, look carefully at any leaking hose to see if the leak is between the inner liner of the hose and the tube it clamps to, or is leaking out of the hose between liner and reinforced core. If it is leaking out of the core, the hose liner is compromised and the hose needs to be replaced.

 

[Brian McVickers]

I had to take it in for a few other things so the Dealer is replacing the Coolant Expansion Tank under Extended Warranty so that will also include a new tank cap and bleed tube. Lets home it works! :safari-rig:

 

[MoGas]

You might also want to check the throttle body gasket. The original design was prone to create a subtle leak that was hard to see under all the hoses but you could smell it, LR designed a new throttle body housing and gasket to fix this. I think the part is around $25.

My 04 was in the shop 4 different times for the throttle body gasket. Thank God for warranty. I had other coolant leaks too. The lower hose at the radiator and a leak at the bottle. It only had 33k when we got rid of it and the leaks developed ~15k.

Dave