Coolant loss from overflow tank
 

Hi:

I’m loosing coolant from my overflow tank. I believe I’m adding about 3-4 ounces to the overflow tank a month. I just changed the oil at my usual 3,000 miles interval last week. The oil looked fine, no foaming at the oil cap. There is no coolant smell in the oil or when the engine is operating. The coolant level in the radiator remains the same, and is full to the top.

I have had the car a little over a year. It now has 139,000 miles on it. The previous owner’s records indicate the UIM was replaced about 8 years ago at about 101,000.

The car runs fine with good performance and good MPG. So, that being said, any suggestions on what to check out, or should I just continue monitor things?


Thanks in advance for any suggestions or direction.


-Jay

Check the bypass hose. And the plastic fitting going into the intake from the bypass hose.
Dale

Check the coolant tank itself. I had same problem and when coolant got to a certain level it would slowly leak from a very fine crack. I had to really examine the tank to actually see it.

I'd look over every area where coolant can be or seep.

TB and the area under it.
Passenger side above the water pump there is an elbow (plastic). There is another (metal) to the left of the water pump and slightly lower. Then the two fittings leaving the alternator tensioner with the heater hoses. Both radiator hoses, and the radiator plastic end caps. LIM/UIM gasket leaking onto intake manifold. All these area's have potential for small seeping/leaking externally.

Internally it's possible the LIM gaskets are in need of changing (if they are plastic, which they are). They might allow a very slight seeping into the intake ports (one or a couple) and the coolant could be getting burned. The easy way to diagnose this is to check your plugs.