I have a 09 Camry Hybrid. Recently I found there was a slow coolant leak from the middle of the overflow tube which connects the radiator cap and expansion tank. (I noticed some red residues on the tube, indicated in the attached pics)

What is the cause of this leak usually? the weak radiant cap, broke overflow tube, or something else? Thank you.

 

I wouldn't worry about it unless you are losing a significant amount of coolant. More than likely, it is leaking ever so slightly where it attaches to the tank or the radiator. Just keep a watch on it and see what develops.

 

Actually the coolant in the tank dropped 1/6 within recent two months. And I found more red residues in the inside area of my car hood, which I am sure is the evidence of the coolant spilling from the overflow tube.

To my curiosity, how come the coolant leaks/spills from the "middle" of that tube, where it's surrounded by an extra thicker tube to provide more protection?

I double checked the tube ends attached with either tank or the radiator, there were no leak sign at all. Any advice?

 

Take it to a tech that has a pressure tester that can put your cooling system under pressure and see where the leak is coming from. If it is a very small leak, they might need to put dye in the coolant, let you drive it for a few days and look at it with a blacklight to see where the problem is.

 

Have it checked out especially if you are under 60k miles and 5 years. There have been many posts of faulty water pumps with really slow leaks that are covered by the power train warranty.

 

I am almost positive, it's the infamous water pump failure. Pulleys and blet simply toss coolant droplets all over the place. Isn't, judging from pic #1, that "leak" on tube insulator right in pulley/belt centrifugal force path?

Look for this:

IMG_0321.jpg

 

As posted in Post #6. This is more than likely a water pump failure. The pic above shows a trail of coolant that is getting "slung" off the pulley and onto the hose in that picture. I bet money that you also have a "coolant trail" on you hood insulation pad as well.

Get out there at night with a good flashlight and you can easily see the pink coolant trails. Look inside the water pump pulley, the hood pad and in the areas shown in the pictures above. If it has been going on for a long time, you will have a "crust" of pink crud on the inside edge of the water pump pulley.

 

Litespeed, you already have confirmation to what you said.
Look at post #3:

And I found more red residues in the inside area of my car hood,

 

Missed that part during the entire thread. If it is slinging it under the hood and dripping on the overflow tube, it's almost 100% certain a water pump issue. Good catch, ukrkoz...

 

Thank you guys. Following ukrkoz's picture in Post #6, I found more "leak" residues right in pulley/belt centrifugal force path, just as ukrkoz said.

My car will go to the dealer tomorrow. The concern is that my 5 year power train warranty just expires five days (Dec 6th) ago.

Anyway, thank you guys again. This forum is really, really helpful!