Looking for some ideas on an overheating gremlin. Chased it for awhile and finally lost the head gasket. Any thoughts on what to check are appreciated:
Rebuilt '88 2.5L, including new waterpump. First start for 10 minutes and temp went to 220. Rechecked everything and same result. Using Evans NPG-R waterless and pressure-less coolant
http://www.evanscooling.com/coolants/Spent 1 hour on dyno for break in, A/F was good. Temps were high again, but with the hood up and 3 fans on the engine/radiator it stayed around 220-230.
On track for test and tune 4 times - 2 to 3 laps each time. When I kept RPMs low I would see 230, if I took it to 5-5.5K it would go to 250.
Changed the thermostat, installed a belly plate under the radiator and bumper cover, hardwired both stock cooling fans, and drilled three 4" holes in the bumper cover above the already open area. Bled system at every opportunity, including with front end jacked up, and jacking up only one side at a time.
Top and bottom radiator hoses were both hot.
Back out on track for 3 or 4 laps, kept RPMs under 5K and temps went to 230 or so. Came in and bled the system again. Let engine cool for awhile and went back out.
First lap showed 220 at lower RPMs, next lap at 5K showed about 230, next lap at 6K showed 245. Decided to call it quits but a few corners later I lost the head gasket.
Coolant comes out tailpipe and was also in the engine bay, but hoses, etc. are in good shape. The coolant system is pressure-less because of the Evans NPG-R.
Have an Autometer water temp gauge and factory gauge - both showed the high temps.
Never had cooling issues with prior motor.
Heard radiator fins can expand stopping airflow but still allowing fluid flow. Will install a turbo radiator.
Any ideas on what else to check? Thanks.