so i bought a '96 xj sport 138k miles that has been sitting for a few weeks and then it sat for about a month before i got it running. i took it on the highway for the first time today and a few miles in, steam just rolled out of the hood and antifreeze was everywhere. i refilled that radiator with water to get me to a buddy's house to work on it. i let everything under the hood dry first then let the engine idle for like 10 mins but couldn't find a leak in the radiator or any of the hoses.. drove it 20 miles to work and it ran just fine anyone know wth had happened?

 

Change the cap. Watch it close.

 

pressure test the system when cold and see if it drops pressure.

 

ok thanks il try both. i know i should also flush the cooling system too. who knows when/if it was ever done.

 

Agreed. Do you know what the level of the coolant before the highway trip?

 

i do not. i ran it for about a week around town and the first day i took it out on the road, i filled the level til it was at the full line.

 

Could have air trapped in the system. Do you have a flush tee installed?

 

negatron, i do plan on flushing the cooling system as soon as i get time. so hopefully that does the trick.

 

If nothing else, I have found that depending on the system that it helps with air bleed.