I recently swapped my motor with another one from my old jeep. After the swap i am noticing that my radiator is leaking coolant right out of the cap. Inspected the neck, no cracks or anything that would cause it to leak. Bought a new cap and it is still leaking. Is my system over pressurized somehow? What could be causing it to leak like this?

 

Could be leaking from the "filler neck" of the radiator, directly below the cap. Not that unusual, especially with an older radiator. Only solution for that is to replace the radiator.

 

Micro crack in the radiator, most likely.

 

I had the same problem. Thought it was falty cap. But no, radiator. Replaced radiator. Problem solved

 

New OEM type radiator with lifetime warranty < $100 at AutoZone my son and I both have them.

 

Im having a similar issue. I have a '95 and when I got it I replaced the water pump because I saw signs of coolant leaking down to the pan. When I did that I found that the previous owner had put stop leak in the coolant. At the same time I also replaced the thermostat with a 180 because it was running 225 in light traffic but okay on the highway. Decided to replace the radiator because I assumed it was gummed up with the stop leak. turns out she started running nice and cool 200-215 in heavy traffic, 180 on the highway. But then it started. The radiator cap was leaking so i bought a new one without the red pressure release and it leaked. So I looked at the cap closer and the tabs on the side that grab the neck just seemed like they were not grabbing tight enough so I took pliars to the red pressure release cap and bent them down a smidge, all was well she was holding great, 3 months down the road its leaking again.

So where do I go from here????

New radiator
New water pump
New 180 Thermo
New upper and lower hose
2 different New caps

Thank You in advance

 

Could be a faulty neck on the radiator itself (even new radiator can come with a fault). like I said in my earlier post, I thought it was the cap as well. Turned out it was the filler neck on the radiator. Just wouldn't seal correctly to any cap I tried. Switched radiators. Solved.

 

Is your new rad still under warranty?
Like Fred mentioned, you guys can get rads for cheap with lifetime warranty...I would not have to think long.