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Burping over heating 1995 dodge neon

Well, finally fixed the car but I now have a new problem.
When I turn the car off, it burps, or bubbles air into the overfill tank.
Car now also overheats when idling or in stop and go traffic.
Temperature goes down when running heater.
Not sure if it is the water pump or an issue with the radiatior.
Any tips appreciated

It burps or bubbles air into the overflow tank because it’s getting air INTO the cooling system…or, actually, rather than air, it’s likely getting combustion gasses.

The overheating may also be because the cylinders are blowing hot gassess into the water jacket that are heating the coolant up faster than the cooling system can dissipate it.

Do a pressure leakdown test. Post the results. I suspect you have a bad headgasket. Sorry.

It may be the head gasket as mentioned above. Another idea: It could simply be air in the cooling system that hasn’t been properly bled. This is especially possible if the coolant system has had work done on it recently. Like a new water pump, etc. Air in the system can cause overheating symptoms. Some engine designs are quite difficult to air bleed the cooling system, but a good mechanic with expertise with your make/model/year should have no difficulty. It should not be overly expensive for a shop to bleed your cooling system. Might be worth a go anyway.

I haven’t done any work on the cooling system unfortunately.
It was real strange, today on the way to work, it heated up, then went down suddenly, then heated up again.
The oil or antifreeze isn’t discolored either.
Any idea if those block fixer in a can might work?

BTW, I’m in Norway and interestingly enough, the Neon is an exotic car. Getting parts for it is quite difficult and expensive.

One more note, the heater blows cold air when it is heating up and then blows warm air as soon as it starts cooling. Not sure why the heater would blow cold air unless the water is not circulating into the heater core. Is this typically controlled by the thermostat?

The coolant is not flowing continuously through the heater core (and the rest of the system) due to the large amount of air in the system.

Combustion leaks are the hardest to fix with sealers from a can. It needs a headgasket and likely head surfacing.

You could perform several tests to see what’s up:
a radiator leak test (http://www.harborfreight.com/radiator-pressure-tester-kit-69258.html) or with a exhaust gas leak test. (http://www.amazon.com/UVIEW-560000-Combustion-Leak-Tester/dp/B000NPDL76). I’m sure you can get those types of testers in Europe. The exhaust leak tester will prove that you have an exhaust leak that expels through the coolant. The radiator leak test will prove there’s a leak in the system somewhere.

Like some of the guys here said, I bet the exhaust gases are making it into your coolant because you have a bad head gasket.

You mentioned the car needed fixing. What did you have to do to get it running again?

I pulled off the EGR valve and cleaned it with Carb Cleaner. I also changed the plugs and the fuel filter.
Unfortunately, after looking into it a bit more, I decided it was better to scrap the car and get a new one. Well, not new but just another one.
So I purchased a used 1997 Honda Civic which now has some problems of its own but is a bit more manageable than the Neon.
And BTW, we I live in Norway which is far different than Europe. I didn’t realize this till I moved here. That’s why they call this place Scandinavia. But it’s been a pain in the rear finding things around here, especially where we live.

If you’d like we might be able to help you with the Civic problems. Feel free to post them.