Hello guys I'm having an overheating issue. Little background info first. I was a master ASE tech for 30 years this one has me stumped. I have had this car at two separate shops also. Here are my engine specs for the cooling system. I have a champion 3 row radiator. March serp belt system, 180 deg t-stat, stock water pump, 2 12 inch electric cooling fans mounted diagonally, vintage air system, autometer pro comp ultralite gauge, also edelbrock aluminum rpm heads (6077). The engine has had a few different radiator caps. The current one is a stant 16lbs. Engine has less than 200 miles due to this issue. Forgot to mention this is an LA360.
First I will start with the shop experiences. First shop stated that my carb was running to rich and causing the overheat issue. I took it to another shop and they said the same thing and tried to work on the brand new out of the box holley carb. This just made it worse running. I went ahead and added a Holley sniper EFI set up on. What a difference in runability and power! Engine is still running hot. I have tried several different thermostats ranging from 160-195. 2 Different water pumps, 2 different electric fan setups. I had all the engine parts IE block and heads, crank ect checked at a local machine shop. Block was bored 30 over. Head gaskets have been tested chemically 3 times and all 3 times negative. The heads were not in the box but were new never used. But some small port work was done on them. This is why the machine shop checked them for me. One weird thing did happen. One of the freeze plugs on the left side of the engine blew out. Both times the engine was at a higher rev. I put a third plug in and it felt like it went in to easy so I JB welded it in. I know this method is not professional but aside from taking the engine out it was easier. No more issues with that plug. I should mention also that no oil or coolant appear to be mixing in the engine or radiator. I also had an oil analysis done and that turned out ok so far.
I decided today was the day to look deep into the issue. The starting coolant was 89f . I live in Florida. I went ahead and ran a suitable fan in front of the engine. The first temp check was gauge read 150f and my two infrared temp guns read 134F. At 180f both cooling fans came on and water was flowing well in the radiator. Next temp reading was 194f at the gauge and the gun read 184F. At this point I stuck in a thermometer directly in the coolant. I left the coolant thermometer in until 205F then I put the cap on. Temperature continued to rise on the gauge and on the gun until I shut the car down around 215F. I did notice that the exhaust temps engine running and engine off were all over the place. The two middle cylinders were as much as 100f difference than the end ones. This was true for both banks. The Left side was considerably hotter than the right side. To give you an example I have my MSD box mounted with an air flow gap under it on the inner fender well and it was 147f with the hood open. The master cylinder was 160F.
Not sure if the blowing out of the freeze plug was a sign. Bad Machine work?? EXhaust temps have me baffled as to why they are all over the place. I dont know if the engine block has some sort of flow issue. Heads issue?? I did order a cylinder leak down tester which will be my next task. I can watch the radiator for bubbles with it for head cracks ect. The car runs great accept to hot.