Coolant system failure

[rutger kohler]

Hi, I have a 1990 Eunos roadster. Several weeks ago we had a coolant system failure which I have traced to a split in a small tee off the aluminium housing for the thermostat. I have looked up previous posts and see somone has removed the tee and drilled and tapped the housing to fit a brass fitting. This seems a good idea as i would have replace the whole housing which looks expensive and a big job. Can anyone tell me the best way to get the old steel tee out as if I leave it in the tapping drill will wander.

[broomfish]

Common problem, New thermostat housing from Mazda is $175 + gst

Hint #1: Do it with the thermostat housing still bolted to the engine. (if you remove it you will need to buy a new O ring as the old one swells up and cant be re used)

If you take the top thermostat cover off and remove the thermostat you can see the back of the fitting easily, you should then be able to tap the remaining piece of the pipe in and extract it from the inside then run the tap and screw in the T piece.

This is a good time to give the cooling system a birthday with a flush and new thermostat and maybe radiator cap, then refill with antifreeze/corrosion inhibitor. I have all this in stock if you need it

[rutger kohler]

Hi Peter thanks for that, good idea, I will try to knock the old fitting out from the inside. Thanks for the offer of parts, I haver already done this and ony discovered the split tee when I refilled with new coolant!