My 98 sls runs about 1 line past normal (12 o clock) operating temperature. It takes about 25 minutes or so to do this, and then its not consistant. Mechanic couldn't find problem. Chilton manual and another mechanic says it could be an air pocket in system but not sure I know how to relieve it. Any ideas on this problem.

 

have you changed coolant lately???? is coolant up to snuff? (full)

 

Normal operation....

 

now thinking about........ agree..... mine has been there on occasion. not to worry, but would confirm coolant is up to where it should be.

 

Coolant is good. New radiator last year. Jusy changed this past weekend. On way home saturday the heater was blowing cold so I checked hoses and one was hot and other cold so I thought my core was bad. I jumped hoses and it still runs hotter. I can start it sitting in drive way and let idle and one time it would go 2 lines past 12 o clock and stay, the fans would come on high.When this happened I used an infared thermostat and temp was 225 on engine side of thermostat and 180 on the other. Then I could start it few minutes later and let run and it would stay on 12 o clock or so and temp on both sides was pretty equal. Sounds to me like thermostat is sticking. I first put a thermostat in from autozone then put one in from dealer (ac delco) just a few weeks ago, there was no change with either, but at the time water was leaking into my cylinder, fixed that recently with gm tablets, seems to be working good. Not sure how old water pump is. My thought is to try another thermostat and then pump. Please help

 

After u changed your radiator, how did the car run idle fine etc? Water was leaking into your cylinder? How I'd gm tablets fix that? Did you get rough idle anywherre during this process? Just curious comparing to my application. I do see the temp gauge move like yours does every now then. Live in south fl beeen 85-90 down here still so ac on and it workin hard. And. My coolant perfect level

 

The tablets from gm were designed to repair head gasket leaking. Call chevy dealer and ask for coolant seal tabs.

 

Yes had rough idle when water was leaking in cyl. Not now. Mine leaked bad enough it caused engine to have so much force on it that it broke the teeth on starter.

 

wow that pretty heavy duty there. But i will make a call for thoese, i think i might have somewthing simialr around that area water in something, althou very slow. When i serviced my colant system a couple years ago and just a couple months ago both times i never added thoese tabs, heard about them but just thought they extened life of coolant not sealed or protected or fixed things as such. But if that works i will e giving that try, got a rough idle that i just cant shake...

 

Can someone explain how to drain coolant from a 98 sls radiator system. It doesnt have a drain plug. Do you pull the small hose from the bottom of the passenger side. Please help.