: Coolant check valve on '82 DeVille 4.1

01-14-07, 06:30 PM
I'm asking this question for a friend of mine who recently inherited an '82 DeVille. The car has been stored in a garage for 12 years, but is in surprisingly good shape. Body is great except for the headliner which has sagged badly. Well, we got it running without too much trouble, and have done a major tune-up including the throttle body, of course changed all fluids, and flushed cooling system. One problem in the cooling system that neither one of us understand. There is a coolant line from the overflow tank to the water pump. The line has a plastic and brass check valve in it which is leaking. We tried replacing the check valve with a section of pipe which allows coolant to flow freely, and the car is now seriously overheating. Would appreciate it if someone could explain what this valve does, and also are they available anywhere. We just covered the brass portion with JB Weld, and I believe it will hold (we'll find out tomorrow), but what is the valve for? Thanks in advance for any info you may be able to provide.

01-14-07, 08:15 PM
This check valve was removed in an 1983 or so recall just remove the valve and plug the ends with caps and hose clamps. the valve helped remove any air in the cooling system and was not needed. thus they were not installed in 1983

01-14-07, 08:47 PM
Thanks for the response, Caddyman. Based on what you're saying, then, the overheating wouldn't be connected to this valve. It overheated with and without a thermostat. The system's been flushed and now has a new thermostat, and it's still overheating. Guess there's some more checking to do. Will run the car for awhile tomorrow without the pressure cap and with the heater on to see if the system has air in it. I know thats a problem with a lot of vehicles today.

01-14-07, 10:24 PM
while it's running, check the coolant bottle for bubbles

01-15-07, 09:04 PM
Make sure the belts are tight. it is very common to find the air pump belt loose.

01-16-07, 08:30 AM
Just wanted to post back with results. Put the JB Welded check valve back on the car and it's running fine--no overheating problems.