wrote:

> I have a 96 Sentra which is using about a quart of coolant every 150
> miles! There is no visible leak, no drip, no puddle. But there is
> sometimes a smell of antifreeze while the car is driven. A mech told
> me he noticed a sweet smell from the exhaust, but I do not notice it.
> There is no smoke of any color from the exhaust pipe.
>
> I had the cooling system pressure tested at a repair shop. They said
> it was fine, holding pressure well, and that the head gasket was OK,
> since the pressure didn't flutter while it was running. They tested it
> with the engine off and with it running.
>
> I pulled all 4 spark plugs. They look normal, just brownish/ rusty
> from being run for about 60K miles or so. (The mech said they looked
> normal, too). Each cylinder has some carbon deposition, and they all
> look about the same. (No "gleaming clean" cylinders cleaned by burning
> coolant.)
>
> Since tyhe cylinders don't look "steam cleaned", I am hoping I am not
> burning coolant internally.
>
> Since I can sometimes smell antifreeze while driving, I think it is
> leaking out somewhere and burning up right away. I've watched it idle
> and looked all over for a leak, or steaming coolant, never saw
> anything.
>
> The oil looks normal too.
>
> I haven't yet driven it up on ramps and looked at it from underneath
> while it idles. That's next, I guess.
>
> The car runs fine, and the temp is normal.
>
> Radiator cap is fine, according to the mech. (But it is awful easy to
> put on and take off).
>
> No bubbles in overflow reservoir.
>
>
>
> Any comments welcome! Thanks
>
The pump can leak to a spot such as a manifold and the coolant will
evaporate while driving.
Either that or a pinhole leak in a hose, hose is my best guess.
Heater core anyone ?