Ok so Honda replaced my shortblock and rebuilt my head approximately 20k miles ago. The car has ran fine ever since however I have slowly lost coolant over time. I have continued to top it off from min to max or a bit more every couple months. After spirited runs and popping the hood you can smell coolant but have yet to find a leak. I recently replaced the radiator cap and have not noticed a smell even after spirited runs. I recently pulled the plugs to find them to be in good shape with no signs of coolant.

Today I tested the headgasket by running the car with no radiator cap for approximately 5 mins. I did not see any bubbles whatsoever but the level of the radiator fluid did slowly climb until slightly spilling over. It didn't seem to want to run to the overflow with the cap off. I assume that this would be normal as the water pump is running but now I am wondering. Any advice?

I am also wondering if it is a small leak from maybe the water pump that burns off before being noticed. Like I said it goes from max to min in a month or two being daily driven.

I plan on going FI again soon and would like to get the piece of mind that everything is kosher.

 

either the car had some air in the system which was slowly being released over time, or you had a leak at the cap. There are also a few hoses that run around the engine which could be leaking slightly if not properly installed during the engine build. They can leak small amounts of fluid without being seen, but you can usually smell it.

The fluid level will rise as it is heated, that is normal.
Fluid won't flow to the overlow tank with the cap off.

Just keep monitoring things over the next month and see if it stabilizes, it should.

 

Thanks, well the rebuild was done over a year ago. I would think air would have worked it's way out by now. Hope it was the cap or a small leak somewhere.

 

They prolly had to put the waterpump in. If the seal on it is anything less than 100%, it will seep out, and the location of it won't let ya see it easily.

 

Would a pressure test catch that?

 

have you changed the cap on your overflow bucket?mine was leaking when i drove spiritly and i smelt coolant.i changed it last year and havent had a problem sence.change your cap and elbow.hope this helps

 

Also make sure that the bleeder valve is tightened down. I had a real small leak through the bleeder valve on the intake manifold.

Be easy tightening it though.. don't want to strip it.

 

Pressure test should catch most leaks but yours is so small it might not. Have you checked sensors on the radiator? If you're rocking the OEM radiator, you might have a small crack that only opens up as the car gets warm...you'll notice from the residue if you look at it though. I had the plastic drain plug area start leaking on my S...enough so that I knew exactly that fluid was leaking just by the smell. Swapped with a Mishimoto and bam! perfect so far.

 

Auto Zone rents pressure testers, make sure you inventory the kit before you leave the store.

 

If they did it, and its not right, why not bring it back to they azz?