Triumphrat

skiTTles · 03-10-2010, 08:23 AM

I posted a while back about my mysteriously disappearing coolant and with me having no visible leaks on my S4.

Well, yesterday's morning ride to work I parked and noticed a few drops (enough to make a a circle with an 3cm diameter) underneath the bike. That afternoon I rode home and no such drops when I stopped.

Today I just came in and parked in the same spot (the dried stain from yesterday's drops were still there) and a similar little puddle appeared.

I can't figure out where it is coming from (I don't have much light in the garage here at work), but the drips (which dripped before I could see them drip, so I don't know where they fell from) are right below the exhaust half way between the oil drain plug and rear wheel. Like right where the swingarm meets the bike but on the right side below the exhaust.

The coolant is also dirty, like it is hitting something before finding the way to earth.

Does this sound like a leak between the reservoir and the engine?

Thanks mates!

Yak · 03-11-2010, 12:14 AM

Thats exactly where the overflow tube goes. Most likely its still coming out of the overflow. On mine, the resevior needs to be on the low side in order for it not to come out the overflow tube, lower than recommended by the markings on the resevior.

BombFactory · 03-12-2010, 11:45 PM

Yak got it. It's not a coolant leak; it's your overflow puke tube letting out coolant because your overflow is overfilled. This is usually caused by someone adding too much coolant to the overflow, or there is trapped air in the coolant system that expands while the engine is hot, forcing coolant into the overflow, but the air is in a place that doesn't allow it to find its way into the top of the radiator where coolant from the overflow is sucked into the radiator to replace the air when the engine cools. A leaky head gasket can also allow the coolant system to be pressurized more so than is normal, and it can inject air into the system at the same time.

skiTTles · 03-17-2010, 08:18 AM

But a bad head gasket would show other signs as well right? I had the dealer give the bike a look over a while back for a leaky head gasket when I had my one time only mystery smoke out the tailpipe and they couldn't find any signs of a bad head gasket (but they did not run a pressure/leak down test).

BombFactory · 03-18-2010, 04:37 PM

A leaking head gasket may not always show noticeable signs to the eye. There could be a very small leak that is causing coolant loss, but not a big enough leak to cause running issues or obvious issues in the oil or exhaust. To rule out a head gasket leak, a shop can run a leak down test and test the exhaust for signs of coolant.