I drill holes in the thermostat plate to allow more bypass flow for my 2002 3.2V6 rodeo 4WD will this help or hinder

At one time (maybe still) you could get a thermostat that had no hole in the flange and we would drill a 1/8-inch hole in it. The only reason is to prevent air from getting trapped behind the thermostat and creating an air lock.

In a modern car such as yours, modifying the thermostat will not improve anything. It may do nothing, or it may cause problems. There is such a thing as the coolant going too fast through the system -- keeping the coolant from picking up the heat and moving it to the radiator. This is a very bad thing.

It is also not advisable to change your thermostat to a temperature lower than the factory recommendation. People used to put in a 160 degree thermostat where a 180 was recommended. This can cause the (relatively cooler) engine to not burn the gas completely and create acidic sludge in the crankcase. These conditions damage your engine and will cause it to fail sooner.

A sludged up engine will also run hotter.

What drilling holes in any thermostat does is , prevents engine from reaching its proper temp (if rest of system is working well) it damages the settings that the thermostat will start to open fully (deforms metal) , this is something that may have worked 30 years ago on cars but nowadays its silly to do

if your car gets too hot too fast , start by first cleaning out the system of buildup (flush/cleaner) second ck your ign timing even on computer driven cars it still can get off . an last inquire about special cal settings for custom thermostats , they are used mostly I n the race an performance industry , as that's were your gonna have to look 4 them

Hi George - On a small engine like that, I can't see it doing anything beneficial, at least not that you would notice. After all, once your engine hits operating temperature and the stat opens it is all one giant "hole" in the plate anyway. I've been around cars/engines/auto work for many years and have not heard of anyone doing this before. It seems to me that if anything, it would just hinder the initial start-up to operating temperature.

Are you trying to solve some sort of slow-warm up or overheating problem? Otherwise, I recommend against putting anything there (holes) not designed to be there - not that you should run out and get a new stat today or anything - but mainly because I doubt you'll do yourself any good.

Best regards -
Mark