451 overheating, even when moving

canajien said

If wasn't burped before, it likely is now.

I opened the rad, and gently revved till it reached 180, then I got out and let it run in its own at about 950rpm for 10 mins while I mucked about.

The coolant was definitely moving around and the temp stayed at 180 the whole time, but it's also 7 or 10 degrees celsius cooler today.

There's a list of things everyone has given me to check, I'll compile it later. In the meantime here's the cooling set up.

View attachment 1716112007

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Just out of curiosity,
Do you have a seal on the bottom of the hood that seals against the radiator support? I have found that when idling with the hood open there's no issue and the engine will run at a reasonable 180-190° BUT if that seal isn't present what happens is heat from under the hood escapes from under the hood lip and it gets sucked back through the radiator and gets heated up and then escapes from under the hood lip again and.....well you get the picture. I have a fiberglass hood so I didn't have the seal. I wound up buying foam rubber from Home Depot and I glued it to the bottom of the hood so it sealed to the rad support. Huge difference. You can try a zero dollar test and put a couple of bath towels in-between the hood and the rad support. Just a suggestion, good luck!