reasons for overheating

My 93 honda civic overheats. I took it to a mechanics(firestone) he did
pressure test and said that the thermostat and radiator have to be
replaced. I had warrenty for radiator from another mechanic so I took my
car back to him to fix the radiator. He said that the overheating is not
from thermostat or radiator it is because the head gashead is gone. I am
confused! what is really happening to my car. I see bubble coming out in
the coolant tank when the engin is on!
ENR

 

Sounds like your head GASKET may have failed, and the engine is blowing
bubbles in the coolant.

One quick thing to try first if there are no external leaks is to replace
the rad cap. If it goes bad, coolant will boil, resulting in similar
symptoms to a failed head gasket. Rad caps are cheap.

 

enravi wrote:

That would be consistent with a broken head gasket. Anyone ever heard of
Firestone actually doing something right?

 

Of course, one of the main causes of head gasket failure is overheating.
So the engine may now have two things wrong with it.

To add to what TeGGeR said above, if there are bubbles in the coolant tank
when the engine is started from COLD, then the coolant cannot be boiling
and the head gasket is most likely gone.

Dan

(This account is not used for email.)

 

Firestone doing something right? I hear it happens sometimes (but
people see the Nessy monster too, sometimes):

My daughter had her oil done there once. Right after that job, the
engine blew by seizing and throwing a rod.
When I found the oil plug missing and went there to yell at them, the
manager said that "99% of the time those plugs don't just fall out"..

At that time I wasn't sure what scared me more:
that they figure that sometimes plugs are supposed to fall out _OR_
that they actually have statistics on it....

They replaced the engine, after much grumbling and arguing on my part.
Firestone may have one or two people at their facilities that actually
know what's going on, but most their mechanics there aren't, IMO.
(or/and they've never heard of a torque wrench).

Remco
..

 

sounds like the headgasket probably is bad. an easy way to tell is to
do a compression test, both with the engine hot and cold. you can do it
yourself pretty easily, the test kit is about $25 at your local parts
store and it only requires you to pull your spark plugs and crank the
engine for a few seconds for each cylinder. Also there is a test a
mechanic can do where they check the bubbles you're seeing for carbon
monoxide, a sure sign it's coming from the combustion chamber.

as long as you're pulling the head you might as well test the
thermostat, you can tie a string to it and drop it in a pot of hot
water on the stove, use a candy thermometer or something to verify it
opens at the right temp. be advised they START to open at the rated
temp, they're fully open at 20-30F higher.

usualy a radiator problem is obvious, IE it leaks or it's really
clogged. while you're at it, have you checked your water pump?