93 Accord - where the hell is the coolant going?

[n8zdogg]

93 accord EX 5 spd f22a - 196,000 miles - coolant keeps going low - no smoke out exhaust - no coolant contamination in oil -- no execessive pressure in cooling system - has me a little baffled- any ideas

[jeffcoslacker]

Get a mirror and a flashlight and look all around like under the intake and down the backside of the block and head, all the heater hose connections, heater control valve, freeze plugs, intake manifold gasket, around the throttle body, etc...

And try to locate the A/C evap drain (where the A/C sweats water from) and make sure there's no evidence that the it's leaking out of the heater core. (You'd usually smell this though)...

Check underneath to see if there is any drops hanging out of any holes in the core support or crossmenber...sometimes they leak slow into a trough and it doesn't spill out until the car is moving...

Coolant leaks on the motor when dried up show as bright white streaks running down from the source...sometimes you never see the drip if it cooks off before it falls.

Can you smell coolant, like after driving it?

[webbch]

If you have a significant leak, this probably isn't a necessity, but I *really* love having a "cooling system pressure tester". It looks like a bicycle hand pump that attaches to your radiator, and you pressurize the coolant up to the rating on the radiator cap (typically on the order of 16 psi).

If you're cooling system is going to leak, it will do it when under the max pressure, and this tool simulates that environment without the risk of burning yourself on a hot engine.

If you still don't find any leaks when cold, then you can get an adapter for it that goes on the overflow tank and can test the system when its hot (i.e. thermostat open, more complete loop). Alternatively, if you don't have the adapter, you can do it the risky way of leaving it on the radiator, but you have to watch the pressure like a hawk to avoid over-pressurizing the cooling system as pressure builds up (since the tool blocks off access to the overflow tank)

Of course, if you have a big leak, there should be telltale signs of where it's occurring without any need to pressurize. I just really like being able to pressurize it and find exactly where fluid is oozing out.

[n8zdogg]

Thanks for the info guys. I'll inspect things a little closer and see what I come up with. It really has me stumped as it doesn't smell like hot leaking coolant at any time and it seems to be intermittent. I was losing about a quart a week when the weather was hot now that is has cooled off (fall weather) its not losing much at all.