I have done a search and have not found a definitive test procedure for the champagne bubble test for testing a bad coolant O-Ring. I have heard some people say to check the coolant fill neck above the water pump for small bubbles upon startup on a cold engine. I don't understand how you could see bubbles if the thermostat is closed on a cold engine. Can someone explain? Am I supposed to check it on a cold engine until it gets to full operating temperature?

Thanks,
Tim

 

Checking it cold should work as there is still the pressure relief valve that will allow bubbles through. Checking it warm is better. Let it cool enough to open the cap, then stick a funnel into the filler neck, run the engine and look for the bubbles.

More definative test is HC tester. NAPA should have some strips that will tell you thumbs up or down...

 

Thanks spurvo

 

shurley, shirley!

 

Not to second guess Spurvo, but has anyone else done this test before that could verify running cold will produce bubbles if there is an O-Ring problem.

 

it verifies that their are bubles in the coolant. usually from combustion making it into the cooling jacket. the napa block tester works well, a pressure test of the cooling sys works well and the HC sniffer deal works also. why are you concerned

 

Not really concerned. I just am selling the car and want to make sure the car is performing well for the potential buyers.

I will check out the Napa strips and try the bubble test again, but longer this time. The first test showed no bubbles.

 

/\ you are a good man

 

i agree... you are a VERY good man. I wish there were more people in the world like you.

 

Thanks, I would just like someone to do the same for me if I were ever to buy a used RX-7. The compression test is coming up next.

 

This is a bit of topic, but I got a couple questions about this procedure.

I also tried to do this check just to see if the smoke/vapor in the morning could be from an leaky o-ring. Or simply is water condensation. Chicago region, and it's been a bit rainy.

Something seems a bit strange though, I let the car cool down completely, i.e. over night. Then I removed the filler cap before starting the engine. The coolant is aprox, 1-2 inches below the very top of the filler neck. When I started the engine the coolant level began to rise towards the top within a very short time. 20 secs maybe. Now obviously heating up would cause it to expand, but that quickly??? Anyhow, I had it run for about a minute before I shut it off to prevent the coolant from spilling out of the filler neck. In that time there were no bubbles of any kind, and the coolant returned to it's original level within in a couple minutes. The overflow sits dead on at full.
Is that normal for the coolant to rise like that? Or am I looking at some other possible problem?

Any thoughts would be appreciated.

 

I also noticed during the test that the fluid level varied. I have a healthy engine, so I think what you are seeing may be normal. The only explanation may be that there is some air in your system that is causing fluid levels to burp up that quickly. Just a guess though.

 

thats why someone said to use a funnel. you can let it rise a little.

to be 100% sure just take it to mazda or a know mechanic and have the PRESSURE test the system.

 

The procedure is very well explained at Scuderia Sciriannis site (try this in Google)