Mopar 5511 6901AA Radiator Cap: Ensuring Optimum Cooling Performance Review

It worked, replaced this with the old one because the old one was no longer sealing it and was leaking coolant under the cap, fixed that.

Arriving in 2 weeks Overseas Pacific Island Perfect fit jeep with 18psi pressure, lid says 18psi with correct part number in description, inner rubber is stronger than my old one.

Works like the original, opens at the right pace. The only thing I did was drill a small 1/16th hole in the top of the thermos to bleed the air out of these 4.0's and let some water through on startup. This is very helpful.

No installation problems. I drained the old fluid, removed a few hoses, unscrewed a few bolts (6-8) and put a new one in. Perfect form, fit and function today. The price was very good. The seller sent quickly. Very happy with the results.

If you have a Mopar part, replace it with a Mopar part. I bought another brand from a discount store and my jeep overheated. I ended up changing the thermostat and water pump before anyone suggested the radiator cap might be the problem. It was a cap. I haven't had any issues since going back to the OEM.

If you drive a 4.0, do yourself a favor and buy a Mopar. More expensive, but I've owned several Jeeps and have had many coolant issues over the years. The cheap ones from the aftermarket will never be as good. You will thank me later. Tons of people at the Jeep Club

My 2004 Jeep Wrangler didn't get to the point of overheating, but after longer drives you could hear the coolant boiling after turning the jeep off. After a particularly long ride, coolant squirted into the expansion tank, leading me to suspect a defective radiator cap. Replaced with the original Mopar cover and the problem was solved. The cooling system maintains the correct pressure and no longer boils.