Allrite I have a 93 fd brand new water pump, new koyo radiator, new cooling fans, new thermostat, bypassed the heater core, and all is well for several weeks and then my car decides to overheat.!!!!!! Put another new water pump in, tightened the belt, pulled out the thermostat, and cannot find any leaks, coolant light does NOT come on, and it still overheats, more at idle than anything?????? PLEASE HELP!!

 

do u have a undertray?

 

YUP...always have partially there though not the entire thing

 

Since the problem is mostly at idle, I'd bet something is wrong with the fans (not going on de to bad connection, etc.).

 

what exact temps or temp ranges are you seeing while driving?
what exact temps or temp ranges are you seeing at idle?

i agree that sounds like something fan related or could be air trapped in the system.

 

I have my fans hooked up on a switch to a separate wired power and ground, to ensure they are gettin good voltage supply. 100-106 Cwhile drive and it is holding., last nite in my anger I looped the line going to the heater core(bypassed it) and this morning on the way to work it was back to running frosty.......I took out my thermostat last nite as well, any recommendations on whether I shouldleave it out or put it back in????

 

This indicates that maybe there WAS air in the system, as gracer7-rx7 said.

I would reinstall the thermostat AFTER TESTING IT. Was it an OE thermostat? If not, get the correct OE thermostat - there have been a number of threads on aftermarket ones causing problems.

Dave

 

Air in the system somewhere. AST there and correct?

 

I tilted my radiator down a lil more and got some air to surface, we'll see, ima pressure test it today, and it was an aftermarket thermostat, make sure to go get an oem one today too.....THX guys....hopefully this works.

 

aight just pressure tested it and found the small amount of coolant coming from one of the turbo/coolant line. moved the clamp down and re-tightened it and it held 19psi in the system!!!!!! I hope thats it