pmccrite

Just when I thought I had gotten my car problem solved, another one appeared. The Car wont stop overheating, I have put a new thermostat, check all fuses and relays, checked the engine coolant temperature sensor,
checked the fans, flushed the radiator, put the orange cool dex antifreeze in it, bleed the line to get the air out, replaced the cap on the holding reservoir, and the heater isn't working now. It blows out warm to cool air. The water seems to be circulating, but not cooling the engine, Any Ideas?

maxxman04

possibly clogged heater core or bad water pump

pmccrite

I thought possibly the water pump also, only its not leaking and its not making any noise. I don't think the water is circulating through the heater core, the heater core isn't leaking and I am not smelling any antifreeze, what do you think?

maxxman04

neither the core or pump need to leak to be bad. i would start by taking both hoses off heater core either at the core or at radiator/motor, then flush water thru it via garden hose. this might tell ya if the core is clogged. also, just to be safe, check the oil for water, and radiator for oil. if motor overheats too much you could end up cracking head and/or block, which will cause more overheating. as far as pump goes, it could be clogged itself inside, so it may not leak even if it's bad.

MDTAHOE

You may still have an air pocket in the system in or near the heater core. Do the cooling fans come on? A clogged heater core will not cause the car to over heat. And unless the impeller fell of the back of the water pump it is not your problem either. They never fall off unless it is a VW or Audi with a plastic impeller. Do BOTH heater hoses feel to hot to touch? Does the radiator feel too hot to touch all the across?

pmccrite

No antifreeze in oil, or oil in the radiator, Thank God! I was afraid to pull that dip stick, I had that happen on a neon one time, at that time I thought some one had intentionally put something in my radiator, but come to find out no one had. With the heater all of a sudden not getting hot almost has to be the heater core, doesn't it? Could the heater core be responsiable for the overheating and the heater not heating? I am almost tempted just to change the water pump anyways, I think its only about a 40.00 part, and with the alternator going out 5 months ago, I just figured the water pump would be next. You know come to think of it I did hear a screech noise a few times, kind of like when the v belt goes bad, but I thought it was maybe the tension pulley failing, could that have been the water pump you think? And how hard is it to change the water pump? I know I thought the thermostat was going to be a 30 minute job, but it turned into half a day.

maxxman04

heater core could be culprit. i might focus on the water pump first. not sure how hard on malibu. what year/motor?

MDTAHOE

If one heater hose is hot and the other is not then the core could be clogged. If both are not hot then there is a flow problem or air pocket. Look at the set up of the hoses a clogged heater core will not block the flow of coolant through the engine. If you still do not believe that go to the hardware store and get a piece of pipe or a connector and bypass the core. In my 15 years working on cars there has only been 1 car that a clogged core could cause over heating and that was a late 80s Grand Am. They used a goofy set up.

pmccrite

Replaced the water pump and flushed through the heater core and it is not clogged. The propeller on the water pump spins and does not appear to be faulty, but went ahead and replaced it. I kind of wonder if the heater control valve is faulty, if that would be what is causing it, or could it be possible that there is still air in the line causing the overheating? Or I have wondered if the idler pulley isn't going bad and slipping, would that cause overheating issues?

MDTAHOE

The heat control valve will not fix it(it may not even have one) I guessing you still not belive me like with the waterpump or heater core. So after replace it you need to work on getting the air pocket out (extremly difficult on these cars). You may need to have the headgasket checked. Are you sure the t-stat is not in backwards? I asked you several questions in my first post which you did not answer. The reason I asked was not for fun it is info I need to help you fix your car and fix it properly. Everyone can guess and throw out ideas but not everyone knows how stuff works. You may have a clogged radiator, defiective t-stat, a cooling fan problem or even a headgasket problem. A headgasket can blow and not mix coolant in the oil.