Here's what happens,,,,,,

   I've always heard that you cannot mix the red and the green antifreeze's,,,and by golly here's some proof of what happens when you do mix em. When I picked up the trk,,a 1998 Nissan Frontier, I noticed two jugs of the red and the yellow antifreeze in the bed and asked him why,?? He tells me a dude at the parts store had told him it did NOT make any difference which one you used cause engine did not know the difference. In almost the same breath,,,he mentions,,you know the engine had started to run hotter that normal but then the timing chain gave out before he had a chance to look into trk running hotter than normal,,,???

  Well,,I got the bent intake valves replaced and lapped the intakes and the exhausts all in and all chambers held the gasoline test for 5 mins,,,,,, When installing the intake manifold on the head,,,I notice this gookie lookin stuff around the thermostat opening. I remove the thermostat and you can see all the dang gookies just about plugged the thermostat opening,,!!! 

I;m gonna try circulating some cooling system cleaner thru the radiator til I'm sure it is not plugged, then do it again when I get engine running and circulate till clean,,,, 

What do you suppose caused this? Maybe the same thing?

 Hey Tom,,,that was my next question as I have seen some at Walmart that says "universal" and can be used in all vehicles,,,,??????

 I'm thinkin,,I'm gonna stick with the green cause it is available most everywhere,,,,

X2. The design engineers should know what is best for their engine. Some of the parts store employees barely know how to look up parts on their computer. An expensive antifreeze if a lot cheaper that flushing crap out or an extensive engine repair.