Radiator Cap Pressure Warning

[buickboy]

Yeah, this was a stupid thing to do, but wanted to warn others about the damage results of using a 25 lb rated radiator cap versus a stock 16 lb cap:

I was at a race and I needed a new radiator cap so a friend lent me a Moroso 25 lb cap. Without thinking of the overall cooling system consequences, i put the cap on and raced the car another several runs. On the return road after the fourth run, i smelled coolant inside the car. Getting out i saw coolant behind the passenger side tire. It was dark and I immediately assumed the big HG blown and trailered the car as motor temps were climbing anyway. Since that day, i tore the heads off, replaced the gaskets and it is running again. Last week i fired the motor with the new gaskets and coolant started dripping behind the pass side tire again. I then noticed that the water was dripping from the firewall and onto the down pipe (not from the motor). It finally dawned on me that d??m radiator cap. I bypassed the heater core and wallah, no leaking. 16 lb cap is now on the radiator!!!!!

The high pressure cap allowed too much pressure to build up and blew the heater core.

Moral of the story: Never ever install a radiator cap rated over 16 lbs.

Mitch

 

[scottyb]

Another moral: Be sure you know what is wrong before major work. I thought the wife's exploder had a leaking freeze plug on the end of the head. The end that was less than 1 inch from the firewall. So, we pulled the motor cause we couldn't get to the plug with any force. Turned out to be the intake gasket just above the plug. I'll be 80 and my friend that helped will still be ragging me about it.

 

[FlyinGN]

This is why I put a 10 lb cap on my GN. Its easier on the whole cooling system.