Block Tester how accurate are they?

[Miras]

I recently took the car to the dealership after it overheated on me and pushed coolant out of the overflow tank. Dealership used a block tester and diagnosed the car as having a blown head gasket. I had the car towed to a performance shop were a compression and leak down test were performed and found to be normal. The shop ended up finding that the plug for the cooling fans was melted. They ended up ordering a new plug and fans. The IC pump was also found to be intermittently working on inspection they found 1 of the wires was singed so it was replaced and the wiring was bypassed. These repairs fixed my overheating problem and the car is running good. After posting a negative review about my experience with dealership I was contacted by the Service manager who asked me to come in and allow another block test to be performed with me present, I agreed and the test was done this morning. The test fluid turned slightly green/dark green. I'm scheduled to put the car on the dyno again next week should I be concerned about the head gasket based on the findings of block test with no other symptoms?

 

[Miras]

Hello.

I know it's old post but maybe the owner are here.

Sory for my English language I'm from Poland.

What's happen with Your car ? The chemical test change to green shows your head gasket are wrong or everything was OK ??

Best Regards

 

[SVTdreamin04]

If you’re using a block tester, yellow means combustion leak or if the aspirator bulb won’t draw air it also means combustion leak. That’s straight from the Block Tester manual.


Sent from my iPhone using svtperformance.com

 

[Miras]

Sorry to bother you.
Thanks for the answer , but green colour ? I test warm engine 6 minutes test and the colour was green (never yellow) I read on the internet that if the test lasts longer than 5 minutes, it will turn green due to evaporation of temperature glycol, etc. As you wrote, if it turns yellow, the gasket is damaged. I was a bit scared that if it is green it may mean a small leak, but after the information I found on the Internet, it seems that everything is OK. I'm paranoid and instead of enjoying the ride, I'm looking for a problem myself, but I just wanted to make sure. Thank you so much for your reply and have a good weekend.
Best regards (;

 

[gmtech]

I have used the block test followed by leak down reliably during my 16 years as a technician. Did you see them put in the uncontaminated fluid into the tester?

 

[Miras]

Użyłem testu blokowego, a następnie wyłączeniu niezawodnie podczas moich 16 lat jako technik. Czy widzisześ, jak wkładali niezanieczyszczony płynie do testera?

I have this test test (another version is popular in Poland, but works with the same method) it is clean. turns green after about 5 or 6 minutes. First, I warm up the car to the optimal temperature, then I do a test. It does not turn yellow, but green. You mean it's okay? Do I need to worry.

 

[Miras]

Hello.
if you find a moment, I will be very grateful for your answer. My car is a Dodge Challenger 5.7 HEMI. When I put the tester on the exhaust pipe, it immediately turned yellow. During the test in the coolant expansion tank, when the engine is warm, it changes color after about 8 minutes, but to a very dark green, I have no other symptoms, I do not know if this is a cause for stress or if everything is OK. Best wishes