2000 Chevy Cavalier Heater Not Working & Thermostat Gauge Rising Quickly

Sounds like your thermostat is stuck in a mostly closed position, there's enough flow to heat everything up, but not enough to cool everything down, so your temperature gauge is telling you that there's not enough coolant flow and it's getting too hot. Have someone replace the thermostat.

Your thermostat may be stuck closed, or your water pump may have failed....in any case you need to perform surgery....

maybe this one 2.2.?

http://www.youtube.com/watch?v=dBkwMCEZE9c

water pump....

http://www.youtube.com/watch?v=_BbBSV4F84Q

Or an airlock or blockage....
Drain the coolant, flush it out (rad & block) check all hoses, check the thermostat works. Refill, check it works.

NB:- Some modern cars have silly little header tanks which can be full while the engine and rad has run dry (this sort of nonsense is call an "improvement). So a full header does not mean the system is full!!!
Del
PS Remove any cats hiding under the hood

Did you check the belt? Water pump is turned by a belt on most cars.

Might it be frozen? I know we are here and if your antifreeze was not up to par it may have frozen.

Symptoms suggest water pump is gone. Don't run the car until replaced or the engine follows. S.M.

I concur. It's possible the heater core is plugged, but this usually comes on gradually. Also, there is probably a cable- or vacuum-operated valve on the hose to the heater core which could be stuck closed, but based on the symptoms, I'd say the water pump is not pumping water to the radiator or heater.

OP, when you say the antifreeze was 'fine', do you mean the strength (mixture %) and the level were ok?

you're misusing the term "thermostat", the needle as you call it is a coolant gauge, the thermostat is inside the engine. its job is to prevent the water from circulating until its hot. it only opens at a preset temp to provide your heat and make the engine run at design temperature.

Internet auction sites (names withheld) are great for solving problems like this. One simply lists the vehicle, then a few days later someone shows up with some money, swaps it for the vehicle, and takes the problem away.

Here is a great use for a Cavalier

http://www.youtube.com/watch?v=PT8U3D7unyI

My trip to Youtube brought that up, and it was ... umm... OK, but the Mighty Car Mods videos that showed in the sidebar were a lot more fun. Sorta like Car Talk with an Aussie Accent. And that weird Aussie sense of humor. Eat a Ghecko cause it tastes fishy? Who knew? Don't let Geico know. It would probably traumatize them, no?

Check your oil for signs of anti freeze losing heat indicates your low on anti freeze. If any signs of anti freeze is in the oil,foaming anti freeze color or it shows on the dipstick as being over full you probably have an intake manifold leak. If no signs are noticed check both top and bottom radiator hoses are hot when engine is up to temperature.

As previously noted it maybe a bad thermostat but I doubt it as Chevy uses plastic intake gaskets which are notated for breaking.

A possibility, and one I ran into, with, as far as I can tell, all the symptoms you list, is that it is cold enough that your radiator is semi-freezing. I have had this happen when TOO MUCH cold air flowed through the radiator. It won't solidify, but can "slush up", making it not pump.

Observed effects are that the engine reports over-heating, the hoses will be warm due to water TRYING to flow back from the engine to the radiator, the bypass hose will be HOT, (since in this scenario the thermostat opens early, and stays open, trying to cool the block, while the water cannot move fast enough through the radiator), and the radiator header (the part you can see if you take the cap off) will LIKELY have visible water in it (not ice, but also not flowing rapidly). All of that was present in my case, and since it all LOOKED to me like the cooling system was working, it didn't make sense.

In desperation, I solved the problem by putting a piece of cardboard over part of the radiator. Seemed totally counter-intuitive to REDUCE cooling of my engine, but it worked fine through that particularly cold winter. Then my brother-in-law, who drove big rigs cross-country for JB Hunt pointed out that the zippered canvas covers you often see over the radiators of semis on the highway are there specifically for this purpose. A friend who owned his own semi and drove it locally said the same thing.

Note, though, if you use cardboard, or whatever, make sure it is stiff enough to stay where you put it, and don't forget to remove it as soon as the weather warms up.

Note also, I live near Washington, DC, and it is fairly rare for us to get a prolonged enough, and cold enough, winter to need this fix. But if you live where it is colder more often, you might just be lucky never to have needed it before.

I know it saved my engine and got me through a particularly bad winter, here.

Thanks for all the feedback, i talked to two different local mechanics and they both said the thermostat is most likely problem. One said it would be a 3 hour job ($40/hour) and almost $75 in parts. The second guy said he could do it for $60 if he orders the part or $50 if i go get the thermostat myself, im going with that option. Hopefully this fixes it. The water pump was checked, i was told it was fine and that the antifreeze is fine and level where its supposed to (& not frozen.)

I'm not surprised it's not the water pump, when that fails it usually causes noisy operation and maybe leakage from damaged seal.

Let us know if a new 'stat cures it.

This is fine just check your oil as previously noted. To get out air pockets you have to raise the front of the car with the engine running.

Note the difference in the quoted price from the two mechanics!

It could very well be just one the radiator hoses collapsing that causing the problem that needs to be replaced?

Take note how quickly the temperature rise when you start driving as compared to when the car just sits there idling? If it takes longer for the temperature to go high, then probably you need to replace the faulty radiator hose? A water pump failure may also show exhibit the same symptoms but will be more expensive and time consuming to replace!

Its possible the higher quoted price is a catch all charge that will cover all the possible problem(s)?

Lift the radiator cap and drive another car under it.

Seriously, the Cavalier was known for head gasket issues. If combustion gasses are getting into the cooling system, a air pocket forms and that could be the reason your heater is not working. The heater core could be full of combustion gasses. Or, you could have two separate issues.

Pressurize the cooling system and pull the spark plugs out. If the head gasket is leaking, the pressure should fall. If the pressure falls, crank the engine with the plugs out and see which cylinder squirts anti freeze out.

...and then tow it to the breakers.

After he replaces the thermostat, make sure he bleeds the air from the cooling loop. Sometimes there is a little bleeder valve at the highest point in the loop. You just crack the valve with the engine running and let the air escape. When anti-freeze squirts out, the air is gone. Very nice. Sometimes the car needs to be tilted. The mechanic should know this.

I have been a mechanic for over 30 years,the temperature gauge rising, without heat indicates one of 2 things either you lost coolant flow, or you lost coolant.your problem is not your thermostat.you will have heat with a thermostat that is stuck closed.you say your coolant level is full so unless you drained your coolant and refilled it recently you shoul not have an air bubble in the system preventing flow.the most likely problem is that the belt that goes around the water pump is gone.if that is not the case and the water pump is turning then the impeller on the pump is off internally.these things,air bubble, broken belt, locked up water pump, or impeller came off are the only things that will cause you to not have heat when your engine is getting hot,when you are full of liquid coolant.

GA. That's exactly my take that points to possible pump failure. impeller got loose inside or was electrolyticaly... diluted.(LOL). Seen it more than once. The scenario of ice blocked radiator is possible but only at very very low temp, if coolant is within specs. S.M.

Got it all figured out, it was the thermostat. Had it changed and everything is back to normal and working fine. Thanks for all the help!

Thanks for the update !! Good to hear you got it figured out.

I'll second that! Often (but not always) we hear no more from an OP and never get to know whether our suggestions were helpful or not.