96 Sentra.. Overheating.. What should I do now???

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.

  1. 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.

  2. 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.

  1. 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.

Reply to
Al Kondo
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Is the radiator like modern ones with a plastic top and shiny aluminium fins or is it all black painted soldered up copper? I say that because the ones with copper fins suffer from the very thin horizontal fins corroding and losing their heat dissipation ability. In fact they restrict airflow through the core (the vertical tubes) and are best ripped out completely if they're rotten.

Reply to
SteveB

That doesn't tell you anything.

All of this sounds like a bad radiator to me.

Reply to
Steve T

You really went the expensive route. Many times it is the radiator cap that has gone bad. This means that the radiator's temperature sensative spring pops open too early thus depressurizing the radiator and letting the hot coolant flow into the overflow container. This is urually the first thing you should always replace when you have coolant problems. The easiest and least expensive fix.

The next step in overheating is making sure the thermostat is working properly. Hoses would be second if you are just loosing coolant but this isn't the case.

Next would be making sure you have coolant flow via your water pump.

Fourth (fifth) is the radiator.

If it had been the head gasket, you would have seen coolant in your oil or steam blowing out of your tailpipe or oil in your coolant. Expensive work for nothing if you did not see any of those sypmtoms.

Hope this helps.

Reply to
Hawaii_SE-R

The radiator cap seems to me like the culprit but if not then your radiator hoses could also be at fault.when the fans are running that meams the thermostat should be open look inspect the inlet and outlet hoses for disfiguration one may have the lining inside callapsed and stopping the water flow and also check the temperature of both hoses as there should be a significant temp difference while the fan is running but if the inlet it is very hot and the outlet is close to room temp then either a hose or the radiator is blocked.if both the hoses are the same temp then the radiator is not cooling(air flow restriction)

Reply to
96xekingcab

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