Coolant block test -- thoughts on these results?

I'm losing coolant and the overflow will be bubbling after a 40 minute drive. I got a loaner pressure tester and confirmed I'm losing pressure. I didn't see any leaks while testing but I also have full skids in place so it's a bit tough to get under and really check for leaks. I got the block tester -- following instructions, I pumped for about a minute (I have videos of all 3 of these - used that as the timer.

Heater was running full blast during the test.

• Test 1 -- coolant temp at 140
• Test 2 -- coolant temp at 165
• Test 3 -- coolant temp at 186 where it sits 95% of the time

I'd call this last test green ... not yellow -- definitely darker than the yellow text.

Test 1 -- coolant temp at 140


Test 2 -- coolant temp at 165



Test 3 -- coolant temp at 182




Unfortunately, I replaced an old blown engine a year ago with a 2007 131k engine. Runs well. no codes. But I do lose coolant and I'm REALLY hoping it's a leak I can track down. I ran this test for peace of mind and I really don't know?

 

It's blown, even though it's not fully turning yellow. The only thing that will cause the color change is hydrocarbons so even a small change is evidence of a HG leak

Given your other symptoms I'd say you have a bad HG

sorry

 

put a borescope in the cylinders with 15psi added to the radiator and had this 15 minute later in cylinder 4 ... 6 is also wet - matches the 0304 and 0306 codes. ordered HG kits, a few other parts and will start the process Sunday.