THE GOODS : With Tires, You Should Try to Tread Water
Question: What would cause a perfectly good tire with plenty of tread to disintegrate? A tire on a used car I bought did just that.--C.F.
Answer: If I could take one guess, it would be water inside the cord body of the tire. Although the inside of a tire is pressurized, water can penetrate into the non-pressurized body and cause steel belts to rust and fabric belts to rot.
It is a common problem during floods, when tires can remain submerged. Hopefully, the car was not submerged any deeper than the tire.
Q: The coolant in my 1987 Taurus seems to be leaking. I had every hose replaced at a huge cost. I have also had the water pump replaced, the thermostat changed and the radiator replaced, but the problem is still occurring.
Now, the dealer tells me the head gasket is leaking and it needs to be replaced, along with some kind of special head bolts. Could that be causing the disappearing coolant?--S.F.
A: The sorry history of your leaking coolant seems like an indictment of your dealer’s competency.
One common mistake that motorists make is to check their fluid by removing their radiator cap.
You should check the coolant level only by making sure that the coolant inside the reservoir, a plastic container mounted on the side of the engine compartment wall, is at the full mark.
By repeatedly taking off the radiator cap, you are allowing air to accumulate inside the radiator and creating the appearance of fluid loss when there isn’t a problem.
The first step in diagnosing a possible coolant loss is a pressure test of the system. A mechanic removes the radiator cap and uses a pump to bring the cooling system up to normal operating pressure--somewhere around 14 pounds per square inch. If the system holds the pressure reasonably well, you can be fairly confident that you are not leaking coolant.
Assuming that you are losing coolant, you may have a leaking head gasket. But you should look for confirming evidence. There should be water in your oil, which typically will create a tan colored froth that you can see on your oil dip stick.
Other tests can indicate whether the head gasket is leaking between the cylinder and the water jacket. In this case, you get either combustion products inside the coolant or excessive moisture in your exhaust.
Finally, the head bolts are not the problem, but if you have to change the gasket they will have to be replaced. The Taurus uses so-called torque to yield bolts, which actually stretch a bit as they are tightened and cannot be reused. These types of leaks can be tricky, so you want a competent mechanic able to diagnose the problem on the first try.
* Vartabedian cannot answer mail personally but will attempt to respond in this column to automotive questions of general interest. Do not telephone. Write to Your Wheels, 1875 I St. N.W. #1100, Washington DC 20006.
