Coolant worries


#1

I recently bought a '97 Mazda 626. Mechanically, everything seems to be fine - its perky and solid, the clutch and transmission seem OK. However, I noticed that I am low on radiator fluid after driving only a few miles. I had the pressure checked and was told that all is well, but they did detect a small seep of antifreeze from one side of the radiator at the seam. We are trying some Stop Leak to see if that fixes the problem. I keep checking the fluid and adding only water (for now, since it is still summer weather). I lose about an inch to two inches in the overflow after driving about 20-30 miles. Is this unusal; should I worry about this? Is there something better to do to keep an eye on things? It does not have any of the following symptoms:

high temperature (the needle consistently hoovers just below the mid-point on the gauge)

white smoke either from the engine or tailpipe

milky fluid around the oil cap

strong antifreeze smell (there is a faint smell sometimes on the driver’s side)

film on the inside of the windshield

water on the passenger’s side of the car

I have been told that there could be a cracked head or a bad head gasket, but I don’t know how to tell either one of these. The engine is fairly clean for an old car, and the performance is very good, both in town and on the freeway. Any suggestions?


#2

We are trying some Stop Leak to see if that fixes the problem.

At best it will hide the problem for a while, at worse it will cause more problems.

I lose about an inch to two inches in the overflow after driving about 20-30 miles. Is this unusal; should I worry about this?

You should not use any, but I am not certain if you are loosing any. Unless you know how to eliminate air in the system and know that there is none, I am not convinced that you are loosing coolant. Does you car not have an over-flow tank??

I keep checking the fluid and adding only water (for now, since it is still summer weather).

Sorry but that fluid is coolant, not just antifreeze. It, along with the water, provides better heat transfer and protects the whole system from corosion far better than just water. You need the mix year around.

I have been told that there could be a cracked head or a bad head gasket, but I don’t know how to tell either one of these

Very possible. You don’t have the tools to properly check it but most professional mechanics do. Have it checked. They usually use a snuffer that detects hydocarbons in the coolant.


#3

It sounds like they found the leak on the radiator, so the obvious solution is to repair/replace the radiator. Do not use stop leak in the system, it is likely to do more harm than good. I don’t understand why the pressure test would be OK if they can see the leak, maybe it only leaks when warmed up. Either way, just fix the leak and flush all that stop leak junk out of your cooling system.


#4

i agree, although, radiatiors arent expensive, yet way too much for how theyre built, on mythbusters even though they are usually wrong, they managed to stop a radiator leak with an egg yolk. try it, and oh yeah, keep dogs away from that car, antifreeze tastes sweet, and dogs wont hesitate to drink it, it will kill them very quick with just a little amount. Hope it helped


#5

Change the radiator. It’s an inexpensive part for your car. Don’t use stop leak if the leak is at the tank. Just change it.


#6

Replace the radiator cap. Any coolant leaks from the cap will accumulate around the seam of the radiator. BTW, the pressure check does not include the cap. If you still lose coolant after replacing the cap, don’t fill it right away. Keep driving but watch it closely. You might have a crack in the overflow tank and it will only go down so far. If the tank completely empties, then you have to refill. You could also wrap paper towels around the overflow tank to detect any leaks.

If the seam is really leaking, and that is very possible as it is just a rubber seal, you could try squeezing the fingers of the tank with a pair of channel lock pliers.