Had an interesting experience over the weekend. I smelled burning plastic while driving my 1988 SE. Popped the hood and found wires running down to the ACV burned to a crisp. One of them had actually burned off of its connection at the ACV. The insulation was totally gone from 4 wires for about 6 inches. There was a melted blob of white plastic from a harness connector on top of the front engine cover. All of this was caused by a faulty coolant cap seal (the one on the thermostat housing - looks just like the radiator cap) leaking anti freeze, which was then blown back by the fan. The coolant then ran down the wires into the connector causing a short circuit. I later realized that if that one wire had not burned off at its connection, thereby breaking the circuit, the entire harness could have burned, with scary consequences. So, check your caps for leaks - It's cheap insurance.

 

This is probably why the later series 5 cars did not have a cap on the housing.

 

Mine's leaking too - especially at higher RPMs. Can I just buy a Stant replacement, or do I need to visit la dealer??

 

What mix are you using for your coolant.

Most of the time when you use 50/50 it does not conduct electricty very well.

 

Joel,
Mazdatrix sells just the cap. Part# 15-2050-KF01. Costs about $15. Dealer will only sell "the assembly," which is the cap plus the little black plastic housing beneath it. About $45. This thing is not a radiator cap - It has no pressure release function, (no spring underneath) and the neck it sits in isn't deep enough for a regular rad cap, anyway.

Icemark,
Don't know the coolant mix %. It's been in there since I bought the car in 2000. Time to change it.

 

Dealer one is like 10-15 bucks. I have a cap that came off a stock 90 GXL. You can have it for free. I forgot what pressure it is, i believe .9 or something. Why do I have it? Well when i bought my car, id id tune ups. I bought a new cap to replace the one on it. It is fine. Just pay for shipping, happy to send it to you

 

Water itself is a poor conductor of electricity. Coolant is even worse. I highly doubt it was the coolant itself causing a short.
Sean

 

Sean,
Water is a poor conductor of electricity????? Grab your ohmeter and place the test leads in a cup of water. You'll be surprised at the results.

 

put water between the posts of your battery. The thing would short and die if you were correct.
Sean Cathcart

 

18460 ohms between 2 inches of de-ionized water at room temp, tested with a DMM, two mins ago.
Sean

 

Salt water (or any ionized water) is a good conductor. Water itself conducts **** poorly.
Study some Chemistry and do your own experiments before you tell someone else "facts" .
Sean Cathcart

 

Sean,
Thanks for the instructive info. Your experiment has shown us that water does indeed conduct electricity, or your meter would have recorded infinite, or nearly infinite resistance as it would on an insulator. You know what would happen if you took a shower while using an electric drill, right? (DON'T try this.)

 

Thank-you for being a *****. Your tone really wasn't necessary.
You are correct that if water didn't conduct electricity, the gauge would read inifinity. But that's not what I said, is it? I said water conducts electricity POORLY. Did you actually read my posts?
De-ionized water conducts electircity very poorly. Your example of a drill in the shower is a very poor when, b/c tap water is ionized. It contains chlorine ions. If you have distilled water in the rad LIKE YOU ARE SUPPOSED TO HAVE, then it would not conduct electricity.
Ionized water conducts electricity. IE: Salt water is a great conductor. Put a battery on your tongue, it hurts. (saliva contains salts). Put that same battery in some distilled water, nothing happens.
Consider this: High tension electronic leads are set high above the ground on iron. The leads are separated by insulators. By your theory, rain water running down the insulators would cause huge power shorts.
Dude, this is High School Chemistry. Really. Maybe you should learn about what you are talking about before you post on here.

Sean Cathcart