I'm having the same issues that a number of people have on here. Fine running stock 3.0, but with a non-lockup converter in 90-100+ temps and 75mph+ on the freeway the fluid heats up dramatically, the pre 91 Monteros were never expected to go much above the then 55mph speed limit. Add in rolling hills and you have issues.

Also if I keep the speed down to 65 it never comes on, hit 75 and it a guarantee that it will eventually come on.

So now I need to get a bit more area for cooling. The fact that the light comes on and with 2-3 minutes of idleing will go back out is indictitive of a system design issue, not a parts failure.

I either need a larger cooler, or a smaller one in addition to the stock one.