mk IV coolent overheat
 

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

Thanks for the ideas pwpanas. I've basically concluded that there is something corroding in the cooling system, just not sure what. I would prefer to replace it before it fails leaving me on the side of the road in a green puddle. Options are; radiator, hoses, pipes, water pump, block, head, heater core, thermostat, heater switch.



I think you might be on the right track with the coolant pipes around the engine. There seems to be several, one that runs the length of the engine under the exhaust manifold.



The car is due for a timing belt in a few weeks. While I've got it stripped I'll be checking all the pipes and water pump etc, hopefully that will solve the problem.
Thanks again!

If your coolant wasn't changed for a loooong time, it's not just one thing that's corroding in the cooling system - it's EVERYTHING! (sorry to break the bad news to you). Of course there may be one or two components that are slightly more corroded than the rest, and these parts might be so far gone that they may fail eventually regardless of your Supra's improved maintenance, but then again they may not fail too. Regardless, simply replacing those one or two parts now will not fix the overall problem. You'll need to follow the steps outlined in my previous post. Coolant (and water wetter) have anti-corrosives, and will prevent further corrosion after a very thorough flush. After that, be sure to change your coolant regularly (i.e. follow a proper maintenance schedule). That's it.

Could not agree more you are the man :P

but please run toyota red the green stuff sucks

whats the difference? i would like to know if there are advantages in using the "red stuff"?

Thanks..

The green stuff uses silicates to help prevent corrosion. These silicates also tend to drop out of solution to form solids, which can clog the system or damage components such as water pump seals. Toyota Red contains no silicates, while still inhibiting corrosion as good as (or better than) the green stuff.

it also dosent pit

"Pit"? What do you mean?