Possible sources of coolant loss.

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08-09-2006, 07:55 AM
HudsonHawk

Possible sources of coolant loss.

The Miata overheated yesterday on my wife at lunch. I took my trailer and pickup up the car to avoid any possible issues. Pulled the cap and could not see collant in the radiator. Got it home and it took 3/4 a gallon of distilled water to fill the radiator back up. The car ran fine after filing it up and had no over heating problems. I checked the level a bout a month ago and it was fine. Now the question:

What are the possible sources of the leak and probability of each to start trouble shooting. Here is what I have thought of so far:

1) Radiator Cap
2) hoses
3) water pump (153K on the car)
4) god forbid a cracked head.
08-09-2006, 07:56 AM
channelmaniac

Don't forget radiator...

Best thing to do is to pressure test the system and look for leaks. In the meantime you can run your hand over the hoses & look for either wetness or crusty dried antifreeze remains.

RJ
08-09-2006, 08:15 AM
Titus

Quote:

Originally Posted by HudsonHawk

1) Radiator Cap

It's cheap... if it is more than a year old, replace it regardless.

Quote:

2) hoses

I had 3 spring leaks over a 3 month period at 110k miles. If they are original, replace them all... there are 9 on a 1.6 car... not sure of the 1.8. (OK, I bought them all, but only replaced 8. I am convinced that one of them 1 is not replaceable without pulling the intake manifold.)

Quote:

3) water pump (153K on the car)

Is it original? Most tend to die by 150k.

Quote:

4) god forbid a cracked head.

Lets hope not.
08-09-2006, 08:29 AM
Miatamoto

- heater hoses
- radiator

(those are the two places where I've sprung leaks)
08-09-2006, 08:49 AM
channelmaniac

Todd & I are pretty close to you... I'm up in Lewisville...

If you need another set of eyes on it just let me know.

RJ
08-09-2006, 08:50 AM
HudsonHawk

No idea about the age of the water pump we bought the car with 143K on it. It appeared to be well maintained but I have no actual maintenance records to back that up.

There is some green crusty residue on the upper hose but unable to determine if its a cap or hose leak. As it is right there by the cap. Or it is possible it could have been thrown off a belt or fan. Very hard to determine. Going to drive it home this afternoon and pop the hood to see if I can find anything. Let the wife take my truck so she would not be stranded if anything happened.
08-09-2006, 08:56 AM
sammm

Get a new radiator cap for it. It's cheap and can't hurt even if it's not the source of the leak.
08-09-2006, 10:05 AM
Majik

Also the thermostat housing. On my car also, I had a non oem metal radiator. The bottom of the rad where it sits in the car had started to leak aswell.
08-09-2006, 11:23 AM
HudsonHawk

Little update. Drove over and got a new radiator cap (have not put it on yet) when I got back to the office and parked I heard a boiling sound. Opened the hood and coolant was boiling into the overflow reservoir. The temp briefly went past the center mark on the drive back to the office then cooled back down to just below center before I parked it. Im gonna put the new cap on before I leave the office and see what its like when I get home.
08-09-2006, 11:28 AM
tailchaser

Quote:

Originally Posted by HudsonHawk

Little update. Drove over and got a new radiator cap (have not put it on yet) when I got back to the office and parked I heard a boiling sound. Opened the hood and coolant was boiling into the overflow reservoir. The temp briefly went past the center mark on the drive back to the office then cooled back down to just below center before I parked it. Im gonna put the new cap on before I leave the office and see what its like when I get home.

Sounds like it's gonna be a lot better...
08-09-2006, 02:58 PM
black roadster

Cap should fix it. Mine was doing that and a cap fixed it. I went with a 93-95 RX-7 cap as it's a 16psi cap instead if 14psi.
08-09-2006, 03:11 PM
Treibenschnell

I don't remember where I read it, but, for an NA, it was better to stick with a stock cap rather than the higher psi cap.

Only if I could find that...
08-09-2006, 03:12 PM
black roadster

Quote:

Originally Posted by Treibenschnell

I don't remember where I read it, but, for an NA, it was better to stick with a stock cap rather than the higher psi cap.

Only if I could find that...

The 14psi cap wasn't working for me. :confused:
08-09-2006, 03:45 PM
Sharpie

Easier to assess as you get more information.....I did have my reservoir spring a leak on me. Still holding water by using some sort contact cement.
08-10-2006, 06:45 AM
HudsonHawk

That looks like it was the problem. I am driving it again today and will see after work. But the old cap was in BAD shape.