ok, here's the story.....

about a month ago my car was constantly runnin hot after it had overheated a couple of times.... it would stay around 230 continuously with no other apparent problems. So i installed a manual fan switch and a 180* thermo. Now, with the fan on all the time, it was running at like around 180-190. Now, i forgot to flick the fan on today and it overheated, and now it is runnin constantly at around 230*, with the fan on all the time. I don't know wut the deal is. Please help, thanks.

 

When it overheated did you do a thorough flush of the system as soon afterwards as possible (ie as soon as it cooled)? If you didn't do the flush fully then a heap of small rust particles will have boiled off the inside of the block, and will have settled in the radiator core causing it to not work very well at all.

You may be able to flush it after all this time, but I don't know how sucessful you'll be. Perhaps some special radiator flushing cleaner might help, but I've never used them.

Si.

 

First, make sure the system is holding pressure. The commonest thing is a hairline crack in the rad either below the cap or the other end below the rad hose. A bad cap can cause overheating. Otherwise normal cooling system service should reveal the problem. Chemical flush agents work well, however remember to use new sealing tablets if you do that. You can get them at any GM dealer or you can use the powered Bar's leak. All GM cars come with it from the factory. When you flush you get rid of built up muck that can plug little leaks, and also the sealer tabs prevent water pump failure which is very common after a flush is done.