Just had my head gasket replaced with arp 625s completely reworked head had block decked new thermostat. When I drive now cruising 70 it runs at 210 idles around 200 degrees. When im cruising and stomp it itll run up to about 230 degrees when I let off however itll drop back down to 210. There are no bubbles in the overflow tank. Overflow tank level is not spitting water out and it and the radiator are staying full at the same level. Could the fan clutch or thermostat be bad? Ive got a 180 degree thermostat to put in it and see if that helps but im at a loss on this one. I also unscrewed the plug on the coolant line that goes up to where the egr cooler used to be and there was no air in it it was full of water. Its also fully deleted 5" turbo back with smarty jr set on 100 hp tune stock timing and torque level 4 thanks in advance for your help

 

You can run your A/C to watch the fan cycle or warm it up to 200 degress and and see if the fan cycle if it is the fan clutch is fine, you can take a look at you radiator, coolant protection level and then maybe replace your thermostat.

 

Replaced thermostat with a 180 and does same thing just goes to 215 instead of 230. I had it running w8th the ac on and when it got up to 180 or so idk if it was the ac or fan clutch but it sounded like one of em had rocks in it when it was engaging. Making sort of a popping rattling noise. Hard to explain. So how do I know if the fan is engaging all the way?

 

Well if the fan engaged it will just kick on their is no variable speed, but if you hear a noise pull the belt off and turn the fan or the A/C compressor and see which one is makeing noise if either one make that noise replace it, but seeing as you reach 215-230 i bet its the fan clutch.

 

update. I got the problem fixed. fanclutch was bad and helped but the main thing was the thermostat. had a parts store one so I switched it out with a cummins brand thermostat and it stays 198-205 now.