2002 Neon not getting up to temp and no heat…

[quote=”parkwoodtech” post=159386]I have an 02 Neon that has been sitting for a while (a year or more) I threw a battery in it and started up and runs and drives perfect. My daughter used this car while she was in high school and my son is now about to start driving it. I took it and got it inspected and it passed and got the tags. I have been driving it around town instead of taking my van just to “work the bugs out.”

While driving it the other night it started getting cold so flipped heat on and noticed there was no heat, it blows luke warm. I happened to look at the temp gauge and noticed it gets a little above quarter instead of half way on the gauge which is where I figure it should be. So I bought a new thermostat from Advance and still nothing. So I got a different thermostat from O’Reilly’s to rule out a bad new thermostat. I have have checked all antifreeze and added it as needed and ran it with the cap off and squeezed the upper hose to try to get any air out of the system. I still have no heat. I have been under the car while running and turned off and see no signs of coolant leaks anywhere.

I have a laser temp gauge and let it idle in the driveway for about 20 minutes and measured the temp on the thermostat housing and it was around 130. I measured the temp on the heater hoses going in and out of the heater core and both are about 130 as well. The upper radiator hose topped out at about 90 degrees. While standing there I noticed the fans kicked on. I turned the heat on high with the fan all the way on and the heat coming out of the vents was only 72 degrees.

Now personally I haven’t driven this car in a while other than the last week so I am not 100% the heat was functioning before or not. I have ran through everything I can think of and short of flushing the radiator or replacing it. I am not fully ruling out the heater core being stopped up, but if it were the heater core I wouldn’t think that would keep the car from getting up to temperature.[/quote]

These cars have a higher pressure coolant system than most. The radiator cap is suspect. Check your overflow after letting the car warm up fully.
Good call on the thermostat, however you should have checked the upper hose for heat to see if its opening or not.

130 what? F or C? If its C thats normal, and its just your heater and coolant temp sender. If its F that is too low, check radiator cap and see if the system can hold pressure.

[quote=”parkwoodtech” post=159389]All temps are F. I actually ordered a radiator cap at the dealer and have yet to pick it up. I will probably pick that up tomorrow. But I can say the radiator cap is a pain to remove. When you twist it, it is like it hangs up. Then after the initial twist you have to press and turn and its almost like it doesn’t want to turn so I was thinking about the cap too.

The overflow has coolant in it. I had it to the full cold line and let it run tonight for about 20 minutes and it would never get up to temp. I am going to replace that cap tomorrow and see where we are at with it.[/quote]

If its the cap, and you have no air in the cooling system, the reservoir will fill up with coolant at full temp, over full. OE rad caps are nice on Neons. The twisting issue you list is normal operation, its for overheat conditions so the rad doesn’t pop off at 300 miles per hour and go through your ceiling if you need to open it when the car is at full temp (NEVER DO THAT BTW, UNLESS YOU LIKE BURNS). Its called a “vent” state, then “open” state.
So its closed : vent : open.

[quote=”DaFirnz” post=159392]If you have a laser thermometer, you can check the temperature of the heater core hoses fairly easy. They should be fairly close to each other in temperature. If it’s clogged, one will be noticeably cooler than the other. It’s important to note that with a Laser thermometer, the further away you are from the target, the larger the area the reading is taken from, so the margin of error goes up.

If the cap is not holding pressure, it will simply puke coolant out as the coolant starts to reach temperature. A certain amount of the ability of coolant to retain heat is a result of the pressure it is under. If the system is not building pressure, the coolant will not be able to absorb heat. Basically, if the cap has failed the system won’t build pressure coolant will spew out and the temperature will never go up.

Being that you just replaced the thermostat, perhaps you have an airlock situation. If there’s enough of an airlock at the thermostat, it will not heat up and open properly.

http://www.ericthecarguy.com/faq/what-to-do-when-your-engine-overheats#SolvingCoolingSystemProblems%5B/quote%5D

Well put, btw make sure when you check the heater core hoses, that you don’t have the blower motor on, and have heat on full.
I don’t know for a fact if the coolant reservoir will actually over-fill when the rad cap fails. I know for a fact it will leak out near the firewall when over-full.
Bleeding air on Neons is tricky, neons.org (if i can link it?) has a good write up on it.
Basically the fans don’t kick on just after the thermostat does as on a Honda, but waaaaay after the boiling point. So you just need to hold the upper hose until you feel its hot then cap it off and turn off the car. Making sure the coolant in the rad cap doesn’t go all the way down. A spill-free funnel helps massively.

[quote=”parkwoodtech” post=159407]Yeah I was curious about that but they kick on like they normally would and run for a minute or so and then go off and they don’t come back on for a few minutes. I am also figuring that the radiator isn’t the issue because the car would overheat. But when the upper hose doesn’t get above 80-90F it makes me wonder if it is not stopped up. But if it was stopped up then I would think it would start to get hotter than a quarter of the way up on the temp gauge while driving. Also I got thinking about the coolant temp sensor but if that wasn’t working I don’t think the car would signal to turn the fans on and my heat should work since the coolant would be up to temp the reading on the dash would be wrong. So I have put a bunch of thought into this.[/quote]

So let me get this straight:

You measured the coolant as 130F MAX.
The fans kick on and off like normal, meaning either a sensor is bad OR the thermostat is never opening.
The coolant system has no air in it.
The temp gauge is not at the proper heat readings.

SO:
The thermostat was installed incorrectly leading to either: air stuck behind it that never lets it hit temp and therefore never open, since the temp sensor is behind the t.stat it operates the fans.
BUT:
If this was the case you would have crazy heat and you would see it on the dash gauge.
OR:
The rad cap is letting out coolant at too low of a pressure, and you would see coolant coming out of the reservoir.
BUT:
You don’t report leaks.
OR:
The thermostat is fine, the rad cap is fine, but the sensor is bad for the coolant, leaving the fans to run at 130F and then cut off when the coolant is too low of a temperature.
BUT:
The car would not cool down if the thermostat was operating at the correct temperature.

Something is not adding up here