Orion62490

Hello Vortech specialists!

I have a 350Z from 2004 with a Vortech which develops 460hp.
A year ago my OEM radiator exploded (the plastic above) while I was driving quietly. I deduced that it was old and brittle.

I replaced it with a radiator and Mishimoto fans, new OEM thermostat but since then I have always had problems with coolant backflow when I push hard until 6600rpm, the 2nd, 3rd, 4th ...
My mechanic did the test of the cylinder head gasket with the reagent but nothing to reportFor other reasons I had not driven for a long time, I purged for a long time with an anti-spill funnel. I don't seem to have any air, but I didn't push too hard on the car.
Yesterday I found myself in heavy traffic for 30 minutes,The gauge in the car is just below half, normal. Here are the temperatures recorded with an infrared thermometer and on the mishimoto cap fitted with a temperature gauge :

I measured 88 ° C / 190 ° F on the top of the radiator (the plug gauge does not seem precise)

177°F at the front



At the cylinder head :

I no longer dare to push hard with my car :-(

Do these temperatures seem normal to you?
Shouldn't I put EVANS liquid without water to avoid hot spots in the heads and boiling?
Thanks for your help!