Overheating Engine... What should I do next??

I have been dealing with an overheating problem on my 1.6 Liter 1996
Sentra for the past 3 weeks. I have done a lot, ,but the problem
remains. I need some ideas.

The problem occurred on a return trip from Florida to Texas. The temp
guage showed that it was overheating so I stopped immediately. Water
in the overflow tank was boiling. I put on my interior heater and
nursed the car back home.

The problem appears as boiling antifreeze in my overflow tank. This
is the first symptom. Later it shows as rising temperature on the
guage.

Here is what I have tried thus far:

1. Had the radiator checked at the shop. The tech did a flow test
with a hose. He forced flow in the upper inlet and watched to see the
amount of flow in the lower exit. The tech indicated that he felt the
flow was good and that my problem was probably from another source. I
brought the radiator home without any work done on it.

2. Checked both fans. They both turned on when the temp show in a
higher range. They also turned on when I started up the ac.

3. Changed out the water pump and thermostat. I have a 120k miles on
this car.. .so didn't think it would hurt to do these procedures.
There was no change after putting in the new units.

4. I changed the head gasket because it seemed that I was getting
bubbling in the antifreeze as I watched it with the cap off. Also,
it seemed to make sense at this point. I also brought the head to a
machinist. He indicated that he didn't think that there was evidence
that the antifreeze entered the combustion chambers of the cylinders.
Since I had the cylinder head off, I changed the gasket.

I should mention that I learned a lot about timing chains, chain
tensioners, gears, and their relationships (ugh!). It took a while
but I got it back together and working.

I'd like to know what you would do next. I am beginning to wonder if
the radiator is still bad and may need replacement. I would appreciate
some thoughts. Thanks.

Al Kondo > wrote in message
...
> I have been dealing with an overheating problem on my 1.6 Liter 1996
> Sentra for the past 3 weeks. I have done a lot, ,but the problem
> remains. I need some ideas.
>
> The problem occurred on a return trip from Florida to Texas. The temp
> guage showed that it was overheating so I stopped immediately. Water
> in the overflow tank was boiling. I put on my interior heater and
> nursed the car back home.
>
> The problem appears as boiling antifreeze in my overflow tank. This
> is the first symptom. Later it shows as rising temperature on the
> guage.

Sounds like the expansion tank cap isn't sealing. If the system doesn't get
up to pressure then the coolant will boil at a lower than normal
temperature. Your problem, which you appear to have spent a fair amount on
already, could be just the rubber seal in the cap costing pennies. A
pressure test would tell but it's probably cheaper to just try a new cap.
--
Dave Baker - Puma Race Engines (www.pumaracing.co.uk)

> I have been dealing with an overheating problem on my 1.6 Liter 1996
> Sentra for the past 3 weeks. I have done a lot, ,but the problem
> remains. I need some ideas.
>
> The problem occurred on a return trip from Florida to Texas. The temp
> guage showed that it was overheating so I stopped immediately. Water
> in the overflow tank was boiling. I put on my interior heater and
> nursed the car back home.
>
> The problem appears as boiling antifreeze in my overflow tank. This
> is the first symptom. Later it shows as rising temperature on the
> guage.

Not Good!!!

> Here is what I have tried thus far:

Tried!! <Gasp>

> 1. Had the radiator checked at the shop. The tech did a flow test
> with a hose. He forced flow in the upper inlet and watched to see the
> amount of flow in the lower exit. The tech indicated that he felt the
> flow was good and that my problem was probably from another source. I
> brought the radiator home without any work done on it.
>
> 2. Checked both fans. They both turned on when the temp show in a
> higher range. They also turned on when I started up the ac.
>
> 3. Changed out the water pump and thermostat. I have a 120k miles on
> this car.. .so didn't think it would hurt to do these procedures.
> There was no change after putting in the new units.
>
> 4. I changed the head gasket because it seemed that I was getting
> bubbling in the antifreeze as I watched it with the cap off. Also,

<Gulp> <shakes - head>

> it seemed to make sense at this point. I also brought the head to a
> machinist. He indicated that he didn't think that there was evidence

Huh? you didn't have the head crack checked??!! >that was dumb<

> that the antifreeze entered the combustion chambers of the cylinders.
> Since I had the cylinder head off, I changed the gasket.

The more things that you do that do not correct the issues at hand can cause
additional future issues!!!

> I should mention that I learned a lot about timing chains, chain
> tensioners, gears, and their relationships (ugh!). It took a while
> but I got it back together and working.

....But why fix something that is NOT broken? I am sorry, I just do not get it!!!

> I'd like to know what you would do next.

how about an engine overhaul -- I mean, you do have over 120,000 miles and you
have already done a head gasket -- could be a cracked block! <a guess

> I am beginning to wonder if the radiator is still bad and may need
replacement. I would appreciate
> some thoughts.

why not take it to a auto repair shop i.e. you may save some cash! -- Let them
know that it overheats -- leave out all the things you did!

BBA

> The problem appears as boiling antifreeze in my overflow tank. This
> is the first symptom. Later it shows as rising temperature on the
> guage.

You're saying that the overflow tanks starts bubbling FIRST and THEN it
overheats?!?

Sounds like a bad radiator cap that is never pressurizing the cooling
system. Try a new radiator cap, its cheap and easy and a common cause of
problems like this.

Radiator cap would be a natural to replace and check it out.

If this doesn't fix it, there could still be an internal engine problem...
A new headgasket was a bold move, but might not have gone far enough. Think
about this...not all internal engine leaks allow coolant into the cylinder.
A crack or leak can sometimes allow blazing hot exhaust gases into the
coolant jackets. A couple thousand degrees of gas temperature going into
the coolant at high pressure can blow past any radiator cap, bubble, and
cause extreme overheating. Not the usual case, but it happens.

In article >, says...
>
>
>I have been dealing with an overheating problem on my 1.6 Liter 1996
>Sentra for the past 3 weeks. I have done a lot, ,but the problem
>remains. I need some ideas.
>
>The problem occurred on a return trip from Florida to Texas. The temp
>guage showed that it was overheating so I stopped immediately. Water
>in the overflow tank was boiling. I put on my interior heater and
>nursed the car back home.
>
>The problem appears as boiling antifreeze in my overflow tank. This
>is the first symptom. Later it shows as rising temperature on the
>guage.
>
>Here is what I have tried thus far:
>
>1. Had the radiator checked at the shop. The tech did a flow test
>with a hose. He forced flow in the upper inlet and watched to see the
>amount of flow in the lower exit. The tech indicated that he felt the
>flow was good and that my problem was probably from another source. I
>brought the radiator home without any work done on it.
>
>2. Checked both fans. They both turned on when the temp show in a
>higher range. They also turned on when I started up the ac.
>
>3. Changed out the water pump and thermostat. I have a 120k miles on
>this car.. .so didn't think it would hurt to do these procedures.
>There was no change after putting in the new units.
>
>4. I changed the head gasket because it seemed that I was getting
>bubbling in the antifreeze as I watched it with the cap off. Also,
>it seemed to make sense at this point. I also brought the head to a
>machinist. He indicated that he didn't think that there was evidence
>that the antifreeze entered the combustion chambers of the cylinders.
>Since I had the cylinder head off, I changed the gasket.
>
>I should mention that I learned a lot about timing chains, chain
>tensioners, gears, and their relationships (ugh!). It took a while
>but I got it back together and working.
>
>I'd like to know what you would do next. I am beginning to wonder if
>the radiator is still bad and may need replacement. I would appreciate
>some thoughts. Thanks.

Did you have the radiator cap checked?
----------
Alex