Radiator problem/questions

[Guest db99wj]

I've got a radiator that has a leak, it is leaking around my drain cock. It only happens when the system is under pressure and it sprays out.

I already replaced the drain cock and the rubber seal was messed up but it is still leaking around it.

My question is and forgive me, don't know much about cooling systems, and this is a theory, could the radiator cap be bad? Isn't it suppose to release pressure and allow the system to "breath" a little? Could the pressure that is built up after I run it and turn it off, be causing it spray the fluid out of the drain?

Am I wrong on the radiator cap suppose to release pressure? Will stop leak help?

Thanks,

[molonlabetn]

Radiator caps are designed to maintain a specific pressure by releasing air, or drawing liquid from the overflow reservoir. Your jeep probably has a 16-18 psi cap.

-Your drain cock might not be tightened down all the way.

-The new drain cock might be faulty.

-The drain port might be boogered up, and not allowing the new drain cock to seal or stay seated under pressure.

-The radiator cap might be faulty, and allowing the system pressure to become excessive... but you would probably notice a high temperature, and/or rock-hard hoses before the failure pressure of a drain cock which was properly fitted. If your system is operating at high pressure, you should seriously have it pressure-tested... you might have a bad head-gasket.

I would bet that the drain port is boogered up, and won't allow the drain cock to seal. Stop-Leak wouldn't be a good long-term solution. A larger o-ring might work... but it's quite possible that you need to have the radiator repaired.

[shaftbass]

Is this a radiator with aluminum or plastic tanks?

[Guest db99wj]

It is an aluminum radiator with the plastic tanks, I replaced this around two years ago because a leak, and when I say leak I mean gushing radiator fluid pouring out!, formed between the aluminum and the plastic, dude told me that he could weld it and it last a day or a few months, so I replaced it.

It has 21psi on the rad cap.

The hose going from the top of the radiator between the fan and fan belts into the top of the motor is not rock hard, it is quite squishy, like a woman's....you get my point. I checked again and the drain cock has the piece where you can grip it with your fingers and a piece coming down from that, I tried to tighten it, but it was in very tight. I also notice I had a little oil on my oil filter:doh:

Not running hot, temperature is in a good range

When we replaced the drain cock, the o ring was smashed/cut up at a spot. So with what I have seen and what you have said, I'm thinking it could be the drain port.

I'm sure glad we are talking about automotive stuff, because this conversation is borderline x-rated when you take it out!