Coolant reservoir level fluctuation?
 

First post on he site: My wife picked up an 08 Sahara last July. I immediately noticed the upper radiator hose was collapsing. After a little research I decided to replace the radiator cap. Voila! No more upper hose collapse. However, the replacement cap was covered in black plastic and rated at 17lbs, direct from dealer. Over time I noticed he upper hose started to slip off the radiator inlet. It would slide back to the factory compression clamp. I worried the hose would eventually slip off so I swapped out the factory compression clamp for a worm drive screw clamp. Problems persisted. A slow leak developed as if the clamp was not tight enough. I cinched it down tighter. The factory hose appeared to balloon a little at the radiator inlet connection. It still slowly leaked. I decided to replace the upper hose with a replacement from napa. All appeared well until a leak developed again from the inlet area. The leak just about drained the reservoir tank. Again the hose started to slip off the radiator inlet. This time I used a ratchet to really tighten up the clamp. I've been keeping an eye on the coolant level and hose clamp connection. So far so good. Two things I noticed, the coolant reservoir bottle level does not appear to change between operating temp and being cold (single digits). Also, the upper hose is extremely hard when at operating temp, especially compared to my '99 suburban. Would it be worth replacing the radiator cap again?

Sorry for the ramblings. Wine + typing on an ipad didn't work out so well last night. Let me simplify my original post: 1.) Should the coolant level in the reservoir fluctuate a lot, little, none with the fluctuations in engine temp? I put a piece of tape on the cold mark this morning. I'll check the level after it's up to normal operating temp to see if there is any change. 2.) How hard/firm should the upper radiator hose be when it's at operating temperature? It seems to me to be too hard. This is why I question the operation of the radiator cap, perhaps causing too much pressure, and thereby causing the hose to move on the radiator inlet.

they fluctuate
 

up and down at cold level it souldnt be way down but certainly chages a you drive , mine went to what I thought was to low they claim it evaporates a bit too but as long as you have some in the tank id just watch it closely jus make sure you add the correct antifreeze for your year jeep their not all the same 12s use different from 13 th 08 im not sure what they used keep checking it in morning when you go out mark it and then go from there each day

I'm thinking your replacement cap is defective. There is a way to check it described in the owners manual but it seems fishy. You can get a full OM PDF download for free at jeep.com if you don't have one. Since you have an '08, do you know if the 5-yr coolant has been replaced with fresh HOAT?

Edit: originally wrote "here's a way to check it..."

I replaced the cap with a stant this evening. I also tightened up the hose clamps at the thermostat housing and radiator inlet. They were still leaking at both locations. Out of all the vehicles I have owned and worked on over the past twenty years, this one really needs the clamps super tight. The ends of the hose are flaring out due to how tight I have the hose clamps. I did notice the reservoir level appeared to rise by about 1 1/2" at operating temp, prior to replacing the cap. To those that replaced the factory clamps with screw type hose clamps, did you really have to crank them down to prevent leaks?

I was always told over-tightening hose clamps could cause leaks. Something about too much compression damages the resilience of the hose material which has to respond to temp fluctuations. Snug is usually good enough.

There is a list of torque specs somewhere. I don't know if the rad hoses are on it but that'd tell you the right pressure if listed.

Found the torque specs, rad hoses isn't on it.

Found this some performance hoses:

http://www.hps-siliconehoses.com/jee...coolant-1.html


Max Torque Spec Recommended Torque = 35 in.-lbs. ; Maximum Torque = 50 in.-lbs.
Remark: Over-tighten the clamps may break the clamps or damage the radiator plastic connector that would eventually cause the coolant leak.

I swapped out the radiator cap with a stant from advance auto, and double clamped the radiator inlet hose. After several heat cycles, I tightened the snot out of the clamps. So far so good.