This is on a 2000 Honda Accord EX V6. It’s been running great for quite a while. I had no issues, no noticeable loss of coolant, etc. While doing some preventative maintenance I decided it was probably a good idea to change the coolant, since I hadn’t done it since owning it, and I have no idea when the previous owner last changed it. Well, I did a 3 drain refills over about a week. To be honest, I didn’t pay that much attention to bleeding the system the first 2 times. I just let it bleed while I did other things. I came back to it, made sure I didn’t see any bubbles, and finished up. On the 3rd fill is when I noticed the problems. (Or hopefully not a problem.) Even after running for an hour or so, if I revved the engine to 2,500 rpm or so until the fans kicked on, then let off the throttle so it it would return to idle, there would be a few bubbles popping up when the fans kicked off. I couldn’t get it to stop doing this, so I figured I must have a leak somewhere. I put the pressure tester on it and found a small leak at the lower radiator hose. So I replaced the lower hose, and while doing it I replaced the upper hose as well just since it’s old.
We’ll, I got back to bleeding the system and I’m still having problems. If I’m still getting bubbles occasionally, although not that often. Last night I spent about an hour bleeding it and thought I got most of the air out, but I was still getting a few bubbles. So I came back to it tonight. I pressure tested it first and couldn’t find any leaks and it didn’t lost pressure for the 15 minutes or so I watched it. However, when trying to bleed it again I was getting even more air. I’ve posted a few videos to show what I’m dealing with.
Here’s what it’s looking like while idling. Notice that there aren’t a lot of bubbles, but they just keep randomly appearing:
About 50 minutes in I did have this happen at idle after revving it, squeezing hoses, etc. However, the video above was more what it was normally like at idle.
If I rev it, and keep it revved up, there don’t seem to be any bubbles as you can see here:
However, if I rev it up until the fans kick on, then let off the throttle so it returns to idle, once the fans kick off I get several bubbles. As you can see here:
I’ve honestly never paid this much attention when bleeding coolant on other cars. Is this normal, or do I have a blown head gasket? All searches online tend to point to a blown head gasket being the cause of bubbles like this, but the videos I’m seeing of blown head gaskets also tend to have much more bubbling. What do I have going on? Is this normal, or do I have major issues? Any help would be appreciated.
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