2000 xj with original 0331 head. My radiator with the cap off will push out some coolant during a cold start. Is this normal? Replaced radiator , cap, thermostat and water pump. I am now chasing a coolant smell from time to time. No visible leaks and no wet floorboards. Good oil pressure and coolant temp always. Coolant and oil look clean.

 

Are you having to ADD antifreeze to the coolant reservoir? Sounds like you are aware of the 0331 casting defect. When that head cracks, the first thing you will see is having to add antifreeze.

For the coolant smell, perform an inspection of all hoses as I don't see mention of you replacing them. The start of a heater core leak is of course also one of the primary suspects when you smell sweet coolant in the cab. Has the heater core ever been replaced to your knowledge?

 

Upper and lower radiator hoses replaced but not heater hoses. Had a few band clamp leaks due to not wanting to overtighten. Since these leaks have been solved no additional coolant needed. Even washed engine bay to remove any residual coolant. Replacement heater core unknown. Yea i know about the head but unsure what the symptoms are. She runs very well. Wondering if the pressure in the radiator at cold start is a symptom? Thanks for the reply!

 

If the cap is off on a cold start, some coolant may be pushed out. I wouldn't worry about that behavior.

If you're concerned that some exhaust gas is getting into the coolant, you can grab a test kit from your local parts store and do a test. If you find exhaust gas traces in the coolant, it can mean head/head gasket issues. Usually this is also accompanied by white smoke from the exhaust and the exhaust smelling of coolant.

Like TJwalker said, coolant smell in the cabin is typical of a leaky heater core. You'll smell the coolant first, then start seeing wetness on the passenger floor and abnormal fogging of the windshield.

I had a 0331 head on a TJ that I bought brand new - 302k miles later and never an issue - despite several times overheating. Engine still runs great last I heard (sold it to a buddy).

 

 

That coolant pressure tester is invaluable for finding leaks.
x1000 on grabbing one of those - it will save hours of frustration.

I wasted hours once only to find I'd done a poor job of sealing the t-stat housing. It leaked too slowly to find by observing but sprayed out like a cartoon geyser using the pressure tester! Found it and had it sealed properly 20 min later.

 

That should be normal. If it is a cold start, then the thermostat is sealed. The pump still spins. There will be some sloshing backward from the pump pumping into a closed system at start. As it warms the fluid will increase in level as well. Both of those would cause a small amount of fluid loss from a radiator because the radiator is supposed to operate under pressure.

 

Thanks to everyone for your support and quick replies. I have not solved my problem yet but i feel i will as soon as i get back to working on it. I have a feeling i will be starting a thread on heater core replacement soon , after i search the forum for info. Not looking forward to that job if it becomes needed.