I have aleak from the thermostat area of my 1990 Mazda MPV.It is located in the lower radiator hose to the engine. I have replaced the ring on the thermostat, sealed the housing together with the proper sealant and went as far as using a seal for a bolt that treads in to hold it on.It is still leaking.Is there another source in that area that may cause this leak or am i doing something wrong. I know that there is no gasket for the housing.Maybe there should be one? Please advise. Thanks.

What kind of sealant did you use? Some sealants dissolve in ethylene glycol, which is the main ingredient in antifreeze. Silicon sealant would be acceptable here.

I'm not sure on your MPV, but on most cars there is a by-pass hose that is usually somewhere around the thermostat. It may be leaking from that hose.

Thanks for the responses.Both were checked and the one at fault was the bypass hose just above the theromostat housing.