Jump to content
CaddyInfo Cadillac Forum

Air in radiator


Recommended Posts

I changed my coolant last week on my 4.9L 92 Eldorado. I've done it in years past without any problems. Seems like I have some air trapped in the system somewhere, because the temp regularly climbs to about 230 before the fans bring it back down to 200 and the process begins again. I topped it off a few times but the radiator seems full now, and the temp is stilling climbing after a week of steady driving. What is the procedure for getting air out of the system? Oh and I added the Bars Leak as usual.

Link to comment
Share on other sites

Typically with my 4.9, when I did work that involved draining the coolant, I used to fill up the radiator to the top (waiting for bubbles to stop to be sure I had all the coolant I could get in the system), and fill the bottle up to hot line (after flushing the bottle) knowing that it would get sucked in when the engine cooled. I would bring the car up to 220 degrees idling to be sure the stat opened and then turned it off... and let it cool, that will allow coolant to be pulled in from the bottle. Before I started the car later, I would check the bottle to see how much the coolant went down and then top off as needed to the cold line. I would take a SHORT ride (watching the temp gage) knowing that the cooling system is not really stabilized yet and return home to let it cool and stabilize, then add coolant as necessary to the cold line the next time I drive it. The next time I drove the car the cooling system was stabilized.

That said, if you replaced the cap, MAKE sure its the correct cap with the spring loaded poppet valve in the center to allow coolant to get sucked in. Also made sure the poppet valve is not corroded/stuck closed, you should be able to pull it down and it should spring back up into position, if I recall rinse it with a hose.

ALSO, make sure that the hose between the bottle and the radiator is not kinked, blocked or split and that the bottle doesn't have sediment in the bottom of it that clogged the outlet. As you know its a NO-NO to put the cooling supplement in the coolant bottle, only put it in the radiator (crushed). I prefer the tablets.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...