it is the neck on the top of the radiator that connect to the upper hose. in the last couple days it cracked really bad - really undrivable now.

the radiator i have now is a replacement Behr. It lasted around 5-7 years (around 120,000 miles) so I guess I cannot complain. The one before that was the original. That one lasted around 180,000 miles. Before this happened, around a couple months ago, I noticed that the car was running hotter than normal with the a/c on, like 150C-175C and 100C with no a/c. Normally it would run at 100C with a/c and 85C without a/c.

So maybe something was going inside the radiator before it happened and pressure was building up. I bought a radiator on eBay for $125. It will come from CA by ground. The guy said it was manufactured by "Eastern". Never heard of it, but I thought I would give a chance. The replacement Behr is $280 and I was never really that impressed with it. If the cheap radiator lasts me 3-4 years, I'll be happy. Has anyone tried these cheaper aftermarket brands, like Wolverine and Eastern?

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1990 Mercedes 300 SEL (320,000 miles)
1994 Mercedes E420 (140,000 miles)