Radiator/Running hot questions...

For those of you who may or may not know I have a 350 V-8 in my van. Over the 5 years I have owned it, it would run cooler in stop and go traffic and hotter on the highway (higher r.p.m.s). I have since put a 200-4r automatic with overdrive to lower highway r.p.m.s, which it has done, but now the van is running hotter no matter what - not to the point of overheating yet but it also hasn't been a very hot summer here. Also, with the new trans, the trans cooler was mounted in front of the radiator. So far I flushed out the entire cooling system installed a new 165 degree thermostat and coolant/water mix - still wants to creep up to 210 degrees. I have a fan that kicks on at about 165 degrees and never shuts off after that. I know my problem could be my radiator. Now come my questions: Is there any reason a new auto trans would affect running temp? Is there a way to tell if my radiator is really for a 6 cylinder? If it is the radiator has anyone found a (somewhat) guaranteed yet affordable replacement radiator fix? Any other thoughts or suggestions? Thanks in advance. Billski

I can't tell you why you are having heat problems for sure, but bet the radiator is the reason. Check at a local shop to see what it will cost to recore your radiator to a 3 or 4 core.

My 92 chevy truck was doing the same thing...would sit around 210 but I'd rev it up then it would cool down a bit then right back up to 210. Replacing the rad cap fixed my problem. The old cap was probably only about 6 months old?! Maybe you'll get lucky like I did

can I recore my stock 65 radiator? how wide will it become? I mean it is 1/2 inch from the fan and the sway bar is 3/4 inch from the front of the radiator? I once ordered a Griffin but it was for 67-70 I didnt want to cut my doghouse out...yes I have a pusher fan on it

Thanks guys! I will most likely re-core or replace my radiator. And I forgot to mention, I also replaced the radiator cap when I did the radiator flush and it, obviously, didn't help.