First off..it's my fault and I admit it. Now the story and question.
Got my first Miata back in mid July of this year. (no complaints).
I checked all the fluid levels before I left the dealers lot. Drove my first 80 miles bringing little blue home. Still all was OK cept I wondered why there was no fluid in that plastic (every car has one) radiator overflow tank.
Since I'm home now, I filled that plastic tank to the correct level for a hot engine with my normal 50/50 mix. Within the next week (many fun miles driven) I noticed that I had a small puddle of anti-freeze on the floor under the car every morning. NOT a big deal. I park little blue in the garage on a concrete floor ever night. I always check the floor under *all* my vehicles before driving every day. This small puddle was there every day until that over-flow tank finally went empty (cold or warm). Figured that the over-flow tank was not that important because of the spillage but also checked the fluid level under the radiator cap and all was fine every day. Nothing on the floor once that tank emptied. Checked the floor every day!
Now....Yesterday (temp in the lower 60's) I took a run into town (10 miles) and noticed on the way home that the temp guage went up to "H" whenever I stopped at a red light or stop sign. A quick rev of the engine would bring that guage back to normal but as soon as it was under any time of load (in traffic) that guage went right back to "H". OK...my thought is...low on water/antifreeze. Instantly stopped at my local American Legion post and gave it a few minutes to cool down then popped the radiator cap. No liquid visible. Got bartender to give me a pitcher of water (1 US quart) and dumped it in. Still did not cover all the "vanes". Got another pitcher and took about a third of that to fill it. OK...drove home (5 miles) without any over-heating. Put the car in the garage again and left it overnight. Next morning still no wetness under the car and the level in the radiator remained the same. Took it for another ride today and the fluid level in the radiator never changed and had no over-heating issues.
My question is: Where did all my anti-freeze go?
I have checked everything I can think of concerning the radiator and hoses and can find no sign of a leak. I'm due for an oil change shortly and check that oil daily. No discoloring or foam seen. Is it possible that coolant will only leak out at driving speeds but not spill out onto the garage floor when parked hot?
Not a big deal for now as I know I must check carefully one more item. Two more weeks and the Miata will be put for the winter, but I'm curious.
Thanks all.
JV
96 Montego (Lil' Blue)