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How would I install a thermostat on a custom built coolant system?

I purchased my 1993 Toyota from someone who modded a bunch of stuff in the engine, including putting in a header, taking out the Catalytic convertor, removing the A/C compressor and moving/rewelding different pipes (including the cooling system pipes).

Anyway, I’ve noticed that it’s heater has never worked, and I just figured I needed to replace the thermostat. In the stock engine, you need to drain the coolant system, and then remove the bottom radiator hose. I did that, and discovered that when he welded the new coolant pipes on, he failed to put in mounts for a thermostat, and there was no thermostat there. Is this fixable at all, or am I stuck without a thermostat (and heating in the winter?)

You may be out of luck on this one if the pipe is welded to the block where the thermostat would normally sit. Getting it back to stock may be near-impossible. I’m not aware of a thermostat housing that can be welded to the lower pipe connection. If the standard thermostat housing is there with some outlet pipe modifications, and the machining on the block is OK, a standard thermostat housing can be found at a junkyard and the stock set-up restored.

I’d love to hear the reason(s) you decided to buy this particular Toyota.

Care to share it(them) with us?

You bought someone’s elses dream, and now it’s your nightmare!


The thermostat has only to do with engine temp. I would look to see if the heater core is still connected. All that has been done can be un done.

a few photos would be helpful. I can’t imagine welding up the seat for the thermostat.