Honda Civic Si 2006 coolant leak

Question

I have a coolant leak under the oil pan. I tried tracing up but could not locate any hose nearby with any problems. The heat of the engine burns up coolant and the smell goes out from the hood. It seems that it leaks worse when the heater is on. The leak is small and now the smell is going inside the car a bit. The coolant reservoir was a bit low and I added more to it. When I do not use the heater it seems to stop the leak. What is this? The photos are from the front of the oil pan all the way up .

The picture with the red mark means the front of the block where I can see the leak at.

Answer 1

It's a bit difficult to tell what exactly is going on in those pictures, so I can't give you a straight answer, but here is the component view of the entire cooling system of the K20Z3:

Use the diagram to locate any hoses or seals around the areas with traces of coolant. Note that the heater core doesn't have any valve or thermostat mechanism. There is always coolant circulating through the heater core; the temperature is controlled by a blend door in the HVAC system.

If you've checked all the hoses, then the water passage seal or a thermostat seal may be leaking. It may also be the water pump, however that's located on the accessory pulleys side of the engine. Also note that the intake manifold hoses may be leaking down onto the front of the block.

If you find out that the leak is coming from a bad seal, I can provide more diagrams for removal/replacement of that part. Also, you may want to remove the front-top plastic cover from the engine bay to get a better view (and at least get a better picture of where the leak is); it's just held in by these plastic clips.