Low Coolant level and a noise

This is my first time here so I am hoping this will help. I have a 2001 3.4 L Impala and for about 2 months the low coolant level light has been on and we checked it and made sure there was coolant. My husaband changed the oil yesterday as routinely needed and now I have this awfull noise that starts when you accelerate past 25 mph and wont stop until you come to a complete stop. I know there is a coolant leak because I can smell it but it doesn't leave a spot on the ground. Yesterday my a/c only works in speeds 2,3,4, and 5 but does not work in spot 1.

This is my first time here so I am hoping this will help. I have a 2001 3.4 L Impala and for about 2 months the low coolant level light has been on and we checked it and made sure there was coolant. My husaband changed the oil yesterday as routinely needed and now I have this awfull noise that starts when you accelerate past 25 mph and wont stop until you come to a complete stop. I know there is a coolant leak because I can smell it but it doesn't leave a spot on the ground. Yesterday my a/c only works in speeds 2,3,4, and 5 but does not work in spot 1.

Welcome on your first post on AF.
If it is losing coolant better start looking for the leak.
And watch the enine oil for coolant in the oil.
If it is milk/white colored you have a major intake or head gasket leak.
Do not drive it untill you get it checked and it is fixed.
MT

I talked to my husband and he said it wasn't a head gasket. What would be causing the noise? Why doesn't my a/c work on number 1? I thank you for your reply, I really do appreciate it.

I talked to my husband and he said it wasn't a head gasket. What would be causing the noise? Why doesn't my a/c work on number 1? I thank you for your reply, I really do appreciate it.

Change the coolant leak to no. 1
Any coolant in the engine oil.
You need to look for that coolant leak.
Put a pressure tester on it and watch for leaks.
Is the noise coming from water pump area?
I would fix coolant leak before thinking about the AC.
MT

A couple of questions to start...Can you describe this awfull noise ie: screech, squeal, hiss, ticking etc. Am I correct that you did not hear this till after the oil change or do I have that wrong? You also state you can smell the coolant but can see no leak on the ground...Are you inside the car when you smell this oder? If you are check to see if passenger floor is wet, check mat and underneath mat. (if it is wet could be a heater core leak or loose hose clamp to heater core)

No coolant in the engine oil. and its like a humming noise. And yes the noise started after the oil change. I can smell it in or outside the car like if I were to pull up in your driveway you could smell it. I have had people tell me they smell it to.

No coolant in the engine oil. and its like a humming noise. And yes the noise started after the oil change. I can smell it in or outside the car like if I were to pull up in your driveway you could smell it. I have had people tell me they smell it to.

On the noise look it over and make sure hoses and stuff is all hooked up good.
Was anything else besides oil change done?
MT

The noise starting after the oil change may have been a coincidence. Your coolant loos problem sounds like a water pump going south since no coolant is getting in the oil.

The heater blower losing speed 1 is a bad blower motor resistor, a common issue on these cars.

Guys i think coolant, noise and A/c is two different problems. probably pump is not sirculating coolant and when it gets hot it trowing thru radiator cap to reservuar and then out. Probably you pump went down and it makes noise. About a/c chek if fan have all levels of speed on heat or just vent. Maybe something wrong with the regulator switch. I never heard that something can be common with two different things. BTW check your radiator fans if they runing well.
Good luck.

Tell you husband to check what iam gonna write . He can remove serpentine belt easylly. Just tell him to remove and start the car then he have to make quik ride around the block. But only QUICK cause it can make major damages (battery die, overheat). Let him see if he have that noise without generator, pump, and a/c compressor. But i repeat he cant run it more than 3-5minute max.

Ok princess1 the noise is a humming sound...you and others can smell in or outside the car...NO wet floor...This causes me to think that you have an overheating problem..there are generally several items that can be the cause of this. Water pump (but most often is detected by a leak from weep hole from backside of pump puddled on the ground) Poor or no coolant circulation due to thermostat not opening all the way or not at all. Radiator cap not holding pressure (this causes the boiling point to lower) which will let hot coolant back to the resevoir or out of top of radiator. Bad temperature sensor, not giving signal to turn fan(s) on. These need to be eliminated one at a time till you find the fault. One other possible thing to look at is the bleed screws of which there are 2, 1 is at top of black pipe near water pump and one on the thermostat housing. One of them could be loose. Make sure those are tight but be carefull, they are brass (soft metal) and are sometimes painted black. The humming sound could be several things as well: water pump, serpentine belt worn..serpentine belt tensioner going bad, belt out of alighnment. Bad radiator cap and loose bleed screw may hum as pressure releases. If you do find what the problem is, please post and let us know.

A common cause of a coolant leak is the heater core. Do your windows fog up if using the defroster.
Put a pressure tester on the radiator if it pulses the gage it is a blown head gasket. Water pumps sometimes leak and then seal up for a couple of weeks and then dump. Look around the radiator with a flashlight around both the upper and lower tank.

My '02 Imp 3.8 has been displaying the "Low Coolant Level" light for several months now and would usually go out after an extended warm up. The other day I decided to find out what was going on with it as many previous checks had determined that there was no leak and the level was appropiate. Well I took the sensor out of the radiator after I removed the corner brace and the battery and disconnected the sensor lead and retaining clip. I then carefully pried the sensor out of the radiator and examined it. I noticed a heavy build up Dexcool sludge on the sensor probe so with the help of a can of WD 40 I cleaned the probe and the well the sensor seats in and reinstalled everything. For the past week now the "Low coolant level" light has not iluminated.