Engine overheating

Posted by gbuchner On 2023/7/30 14:54:14

Dear Packard Friends,
I am from Austria and have been having massive problems with engine overheating when driving uphill on my 1951 250 convertible.
Chronologically it has happened as follows:
In 2021 the freshly overhauled car was thermally perfectly fine, I was driving in the vintage rally "Ennstal Classic" and this went over some high mountain passes and the temperature gauge was always right in the middle of reading normal.
Unfortunately, I had to disassemble the cylinder head due to a breakage of a new valve spring and found that the engine block had a crack on the right stud between the 4th and 5th cylinder.
Since I wanted to do another vintage rally in the fall of 2021, I mounted the cylinder head with a new gasket, but could not tighten the nut on these studs.
To keep the water loss under control, I installed a cooling system sealer.
Unfortunately, I forgot to remove it after 10 hours of operation and left it in the cooling system until spring 2022.
Since 2022, the engine gets warm on small climbs and it always starts to boil when going uphill high mountain passes.
Now this year I rebuilt and installed another engine, installed a new high performance mesh in the radiator, checked all hoses and tested the engine with both water pumps (I have 2 different ones).
It still gets just as hot and even with the new engine the head gasket is already damaged again.
Now I am already very desperate, because I can not find the error!
Maybe you can still give me tips on what else I can check.
Many thanks!
Georg Buchner