mk IV coolent overheat

[pwpanas]

Originally Posted by shinobi

I've recently bought a 94 NA supra which I knew had some probems. The guy I bought the car from told me that he had taken the car to his dealer several times for overheating problems. Eventually they replaced the radiator and fitted a filter in the top radiator hose. They said that rubbish in the cooling system had been clogging the radiator. Problem is that this filter is blocking up much to fast.

Does anybody know what is breaking down in the cooling system? It looks like flaks of a bakelite lining off something?

If coolant isn't been changed in a loooong time (several years), it becomes corrosive. Every passage in the cooling system starts breaking down.

Best for a cure is a continual flushing until the water coming out stays clean...this continual/constant flushing process may take half an hour or more to flush out ALL of the loose particles. You can use a kit from your local auto supply store, and a garden hose. Be sure to run your interior heater while you're flushing. After that, replace with the proper mixture of coolant and distilled water. If you're going to roadrace, also add some water wetter.

Worst case, some of your cooling system's components have become internally corroded to the point of failure, and they will need to be replaced. Don't worry - you'll know when they fail...just keep a close eye on the coolant temp gauge on the dash. Cooling system parts prone to failure in this situation (in the TT - the only model I work on) are the water pump and the pipe that joins the heater hose above the #6 spark plug.

Oh, and get rid of that silly filter the dealer put in ... it'll only impair the effectiveness of your cooling system. I really wish there was a law against dealers' mechanics doing absolutely idiotic 'repairs'.

More info here:
http://www.mkiv.com/techarticles/coo...ush/index.html