Whiff of coolant while running

Hey Guys

My 98 has 125k on it, and when it's running, up to temp, i get small whiffs of coolant coming from the engine bay.

I haven't had it quite long enough to tell how fast - if at all- it's going through it. Coolant level in the overflow is fine. Heat blows hot. Truck gets up to temp and stays there, no signs of over heating at all.

The 4.0 has plenty of power, no white smoke or burnt coolant smell so I don't think it's eating it. Nothing on the ground that I can see, no whisps of smoke like it's dripping on the exhaust manifold. No smell in the interior even with the heat blasting.

Anyone have any ideas? :huh:

The rad, waterpump both look original to the truck, but I'm chomping at the bit to replace them and see if it solves this...

Around the weep hole near the water pump bearing, behind the pulley, is a likely spot. Really hard to see in there. I usually tape a piece of paper towel on the end of a piece of wire , bend it a little, try and stuff it behind the pulley and see if it comes out dry or not.

The bottom radiator hose, at the water pump, is also a likely spot. They often tend to seep there.

Inner upper right hand corner of the radiator near the end tank, behind the fan shroud, is also a common spot. I don't know why, but many tend to seep there. Sometimes you can the residue with a mirror and a flashlight.

1. Call local parts store that rents tools.

2. Ask if they rent a UV light and glasses.

3. If they do, purchase a bottle of UV coolant dye from the store, add it to your cooling system, then drive around for a half hour or more--then use the glasses and UV light to locate the leak.

That is about the exact mileage that my original radiator begin to fail on my 99. Exact same symptoms as you are seeing. Smell of coolant in engine bay but no drips.

The plastic "seams" on the OEM radiator are usually the first to go. Take a closer look while you are under the vehicle with a good light. As well as checking what the other guys have noted.

If you replace the radiator, replace the water pump. And any other cooling system parts that are long in the tooth like all hoses, thermostat, etc. Cooling system parts are not that expensive and are about the best money you can spend on your XJ.

Thanks guys, that's pretty much what I figured. Cheap insurance. Now who's got the best cooling system overhaul write-up? aperwork


Radiator
Water pump
Water pump coolant tube
Upper & lower radiator hoses
thermostat
thermostat housing
Intake and return hoses to the heater core

clutch for the fan?
what else?
serpentine belt
idler pulleys?
:dunce: