Last week the hose going to my oil cooler burst when I turned off my car. That got replaced, filled the coolant back up, everything has been good. When I got to work today as soon as I turned the car off there was steam spewing out of the sides of the hood. I popped the hood and there was coolant everywhere. To hot to do anything so I went inside for a while. I just went out to see if I could find what burst and I did.

The petcock burst completely off of the radiator. I was in the understanding that this we like the plugs on those cheap squirt guns you used to get as a kid where you could pull it out to let it drain, but there was a piece inside the radiator so it did not come out completely. Well mine is no where to be found and I figured it had just come off because there was no "trail" of fluid leading toward the parking spot, just a giant puddle underneath.

If someone could get me the part number for the petcock to a stock radiator in an 87 350 I would appreciate it. I might be able to get a co-worker to head over to CAP (Consumer Auto Parts) or Auto Zone to pick on up for me.

Also, what could be causing the pressure buildup as soon as I turn the car off which is making all these things burst. I would really appreciate the help. Thanks.

 

The drain plug can easily be removed from the radiator so nothing unusual there. However, it also screws closed, so you have something going on that's creating enough pressure to blow it past the threads and out of the radiator.

What condition is the radiator cap in? The proper cap should allow any excess pressure to escape the system. The factory cap is rated at 16psi, IIRC.

 

I don't remember the part number, but Weatherhead makes a replacement.

 

Ok, first I want to help out anyone else who searches for this later, here are some keywords:

drain plug petcock draincock burst pressure cooling radiator rad

I searched for many combinations of those words so hopefully that will help someone else. The part number for the replacement I got was 61109 as seen here


The original busted one is here


I found the outer part lodged up against some other part in the engine bay about 5 inches back from where it should have been. The inner part was still in the radiator. Let me tell you, that is real real hard to get out without any tools. Luckily my friend had some pliers that fit down in there so I could grip it from underneath the car. The new one popped right in, no problems.

As you can see with the old one, the threads are not stripped, nor did the entire unit come out. The shaft of it just split in two. As far as I can tell the radiator cap is functioning as normal, because when I got home after fixing all this the overflow tank was higher then when I had left. I have access to a pressure tester so next time I am over in that garage I will see if I can get the whole system up to 16 psi without something else blowing off.

I appreciate the help from you guys. Anyone have any ideas that would be causing that much pressure when I turn the car off. Also, my fans don't come on/stay on when I turn the car off. Are they supposed to because I don't ever remember them doing so and it certainly seems like they should. Thanks again guys.

 

How did you replace the oil cooler lines? Can you get direct replacement parts, or do you have to custom bend your own lines?

 

It wasn't the steel lines going to the oil cooler, there are pieces of rubber hose connecting those lines to the cooler. The hoses were about 3 inches in length, just enough on each par to throw a clamp on. I just sliced them off and put new hose in. As far as replacing the actual lines... I don't know about that, I would assume you would be able to get replacements from GM, but I am sure it would be a lot too.