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Thu, Oct. 16th, 2008, 04:06 pm

I've had a coolant leak problem with my '90 Miata ever since I bought it. First it was something with the heater core, and it stopped leaking for a while after a hose was replaced. Then, it was the upper radiator hose. Next, it was the radiator. After I got the radiator replaced, I was tired of fixing the coolant system and I've been adding coolant whenever the reservoir got low. I kind of forgot about it for a month (since school started) and I had to add about a gallon of coolant the other day. Well, it was about half a gallon of water and half a gallon of (50/50 premix)coolant.

A few days later, the charge idiot light came on one day after I started my car. I drove it for about a block and it went off. I looked in the manual and it said that the charge light would come on if there's something wrong with the alternator, battery, or the belt that runs the alternator and the water pump. My car's been making belt noises for a while now, too. Pretty much every time I start my car, the charge light comes on for about a block or two before going off.

How serious is this? I drove about 1000 miles in the last six months and might drive another 2000 miles in next eight months, before I buy a new car. I don't want to spend any more money than I need to on this car.

Thu, Oct. 16th, 2008 09:38 pm (UTC)

hey, an Austinite! I visited Austin for a weekend while I was in Texas for job training--cool town.

How often do you drive the car? The charge light comes on when the voltage in the charge system falls below a certain level. If the car sits for a long time, it might be the battery holds enough power to start the car, but just low enough to trigger the light

Check the battery grounds and test the battery. If the battery is fine, try putting a new alternator belt in. If the problem continues, it might be a loose belt. If a new alt. belt doesn't do anything, it might be the alternator.

I've also had my share of bizzare alternator problems, both in Toyotas. One was in a '92 LS400. The PS pump was dripping on top of the alternator, which fried it. The other was in an '86 AE86 GTS (I should have kept it--got it for $50 and a latte) where a short in the alt. blew the main fuse.

Thu, Oct. 16th, 2008 09:40 pm (UTC)

I drive the car every day to the bus stop, which is about 5 miles/10-15 minutes. how hard is it to change the alternator belt? the battery is about two years old and not OEM :/

Fri, Oct. 17th, 2008 12:24 am (UTC)

For the alternator belt, I'd say probably 4 out of 10, 10 being difficult. You could try downloading the service manual somewhere online and see if you think you can do it yourself. It would probably take me an hour or two and half that time for an experienced mechanic. The belt is probably $20 or so.

As for the battery, auto parts stores will usually carry a version that's constructed the same way as the OEM version. Miata batteries tend to last around 7 years, and some people have seen 10 years on theirs.