DaveyJJ

Hi everyone,

Seems like I've got a disappearing coolant issue with my 4 cylinder automatic 1999 Honda Accord (220,000km on it). The car is mostly an in-town car and work is only a 10 minute drive. There is no leakage on my garage floor or in the level parking lot at work.

Yet twice in the past month I've been highway driving and when it gets into stop and go traffic the temperature starts to climb. Start driving at highway speeds and it cools down again to about 1/3 up the gauge. But both times I've opened the hood to find the coolant reservoir almost empty. Top it up and it's good to go. This last highway trip though I filled the reservoir and 100km later it was low again.

The engine isn't backfiring or sluggish so I don't think I'm leaking into the engine block itself. And the heater works fine in the car. Oil is the normal colour.

So, where might it be going and how can I test to see if that's the case?

Thanks so much for any advice.

David

jdowen2

I had a similar problem. Found a pin hole leak in one of the radiator hoses.

holmesnmanny

You're going to have to just find it. With the car good and hot, you need to gently grab hoses and, without attempting to make matters worse, gently wiggle them until you find it.

DaveyJJ

I'll look into that, and will post results, thanks.

DaveyJJ

Nothing I can see on the top hose. Is the bottom hose the big one running vertically in the collar then towards the back top left (looking at the engine from the front)?

PearlsOwner

Going to want to do or have a pressure test done if you cant physically see or find the leak. I cant say were its coming from for sure without being with the car as it could be a number of places, here is a few ideas though. Get under the pass side dash and check around the heater core, see if the box or the carpet is wet or showing signs that it has been. Could be a pin hole in a hose like said, check all hoses especially where they connect. Could be a small pin hole in the head gasket leaking externally. Water pump, thermostat, radiator and even a pin hole in the over flow container itself. Look around all those looking for signs of wetness or anything that may have been wet, will be a stain, could look white to yellowish-green colored residue depending on where your looking. With the radiator make sure you look at it all, front, back, sides, around both hoses and the fins.

DaveyJJ

I want to thank everyone for their help.

Got it to a really highly rated (and helpful) indie mechanic in Kitchener, Ontario who found the leak for me via a pressure test.

It was in the small short line at the back top of the engine that runs into the (throttle body?) that sends coolant through for cold engine starts and regulates the throttle by way of coolant temperature (does that sound right?). I could see the crusty white-green discharge and drops in places under that hose. New hose and clamp and all done. Got a couple of other small things taken care of at the same time (slightly weepy valve cover gasket etc) but came out way less than Honda has suggested it'd be.