Where did my anti-freeze go?

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)
Reply to
JV
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Well, you've obviously got a leak. You're losing some (most) during driving, when the system is up to temperature (and pressure). When you park the car, the system cools down, relieving pressure, which is why you only see a small puddle under the car.

Get the system pressure tested, and replace anything that leaks. The sooner, the better. These things usually don't fix themselves.

Mike "Red '97" Verive snipped-for-privacy@mverive.com

Reply to
Michael Verive

Thanks Mike...seems that was what I was afraid of. Tis nice to hear a verify of my thoughts. In your opinion (and any others here) since I plan on parking this car in the garage for the winter months (Nov- Apr) do you think there might be a problem parking it the way it is now (still driving). ?

I've looked a nd looked and have never found a leak anywhere. I *do* believe you are correct concerning the leak. Damned if I can find one though. I appreciate your reply. I'll continue looking.

Thanks

JV

96 Montego (Lil' Blue)
Reply to
JV

Agreed. Also, with the car on a lift, shine a flashlight up the front of the engine and look for green drips at the water pump.

Reply to
Lanny Chambers

JV,

Why park the car during the winter months? Are you *that* far north that you'll get too much snow to drive through? I'm in Chicago, and drove my baby last year, including multiple ski trips through fairly deep snow, without any hesitation. She handled better than most of the other vehicles on the road, including SUV's, trucks, and various FWD's. Get some decent rubber for conditions, and drive her as long as you can.

As for the repair, as I said before, take care of it sooner than later. It's probably a tiny leak now, but why chance it? It's not likely to get any better by itself. Also, don't wait until the winter rush - auto repair shops here are fairly slow this time of year.

Mike "Red '97" Verive snipped-for-privacy@mverive.com

Reply to
Michael Verive

OK...Thanks will do this week.

Will let ya'll know what I find.

JV

96 Montego (Lil' Blue)
Reply to
JV

My best guess is the waterpump is leaking while you're driving (in addition to the broken overflow tank). Park the car and leave it running for a while to see if a puddle forms under it, then look for where it's coming from. If it's the water pump it will run down the front of the engine and be probably sprayed in a line on the belly splash shield by the crank pulley. Had this happen to mine recently; it didn't leak at all if it wasn't running; couldn't even find any residue.

If that's not it, it's possible (2nd worst case senario) that it's a blown head gasket into a combustion chamber.

John ('94 Miata) jsgmcclary at cox dot net

Reply to
John

Every time I have had disappearing antifreeze on a car with no visible leaks from hoses or radiator, it was the water pump. On some cars, this is easy to replace. More work on a miata. It's a $70 part and the dealer will ask around $300-400 for labor. And it may be a good time to change the timing belt if it has never been changed.

Whatever it is, best to get it tracked down as you almost went dry on the road. A miata driven for even a short time w/o any coolant can easily overheat and warp the head.

Reply to
Hal

Hi Mike,

I'm not really that far north (central Maine) but I do live out in the woods with a very long uphill driveway. I have a big old Toyota 4Runner that I will use this winter. Unless there is 6 or more inches of snowfall I don't even snowblow that driveway, just kinda pack it down. My city and state are not too diligent about removing high snowbanks at intersections and that 4Runner allows me to see over a lot of them. I'll miss driving her but it will be another reason to hope for an early spring. Li'l Blue has an appointment with my favorite mechanic for next Tuesday.

Thanks for the reply.

JV

96 Montego (Lil' Blue)
Reply to
JV

Speaking of water pump.

I have to get my timing belt changed soon.

Is this the time for a new head gasket and water pump as well?

She's done about 220,000 km

Reply to
Per K. Nielsen

I would replace the water pump at every second timing belt change. I'd also replace the timing belt idler and tensioner at the same time. You're probably a bit overdue for your second timing belt job, right?

Don't replace a head gasket that isn't leaking. You will need a new cam cover gasket and cam angle sensor O-ring, though.

Reply to
Lanny Chambers

First timing belt change at 102,000. Yes, the second is a bit overdue.

Perhaps I meant cam cover gasket? Excuse my ignorance, but which is which?

Reply to
Per K. Nielsen

The cam cover is on top of the head. The head is on top of the block. Here's the order, from top to bottom:

Cam cover Cam cover gasket Head Head gasket Block

The cam cover is removed when changing the timing belt, and the old gasket is not reused. The cam angle sensor is mounted to the rear of one of the cams (intake on 1.6, exhaust on 1.8); its O-ring is a common source of leaks, but it's cheap and so easy to replace while the cam cover is off that it should be done as a matter of course.

The head is only removed from the block to service the valves, rebuild the engine, or replace a leaking head gasket--major stuff you probably won't need for a long time. It's never part of scheduled preventive maintenance.

Reply to
Lanny Chambers

In that case I meant cam cover gasket. It seems to be sweating a bit of oil on the rear left hand side.

Reply to
Per K. Nielsen

Crap, that's the exact symptoms my car is showing recently. When it was newer, it had a bad upper radiator hose, but it's clearly not that this time. Oh well, it's 60k time anyway.

Reply to
Matthew Russotto

I won't bore you with details of my fiasco with the cooling system this year, but it may well apply in this case. If you haven't found the problem yet, sound off. I had a situation that mirrored yours pretty closely and it may be that we had the same problem(s). It wasn't exactly an "easy" fix really, but it wasn't costly or too horribly tough. I usually can find a little extra time a lot more easily than I can find extra money, so this worked out okay for me!

My guess is that everyone saying to check the water pump is correct. However, you REALLY need to replace that broken overflow tank!!! I wasn't aware of the active role it plays in the cooling system until I had my run-in with it, but it is very important to a closed system!

Good luck!

Reply to
Gary Ball

Thanks for the reply Gary. We (my mechanic and I) Finally found a very small crack in the plastic top of the radiator. Don't know why it didn't leak constantly but it didn't. Replaced the whole radiator for a reasonable price and now things appear the way they should be. Drove it around for two days without any loss of anti-freeze. Will need to wait till spring for further checking as Li'l Blue is now securely parked in the garage till winter and mud season ends. :(

JV

96 Montego (Lil' Blue)
Reply to
JV

JV,

Cracks (small or large) may not leak unless the system is under pressure.

Good luck - sounds like you've got the problem fixed!

Mike "Red '97" Verive snipped-for-privacy@mverive.com

Reply to
Michael Verive

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