I've been having overheating issues with my 95 f150 132k miles 5.0 automatic 4x4.I started replacing the coolant system components (burping until no bubbles for every part)with no improvement every time,Started with the Radiator,Thermastat,heater core,water pump,lower main hose on radiator and coolant temp sensor (because gauge wasn't working)than had a local reputable shop do coolant test and they said everything was fine with the head gasket and have good circulation.What was happening is after running for 20-30 min the upper main radiator hose would get very hot and look to be very expanded than the rad cap would burst out coolant or lower hose would blow off losing most of the coolant,the engine also got very sluggish every time the engine would get to operating temp.I have replaced the rad cap twice.also note the coolant temp gauge still don't work.Ive done a tune up with wires,cap/rotor,plugs and air filter.Truck runs like a top until it warms up than all hell breaks loose.Not exactly sure if it really is overheating because of the temp gauge not working but sure seems like it is or could be not circulating properly....Please help!! Need this 4x4 for the winter,thanks.

A worn water pump is the most likely. If the coolant is going down, the water is going somewhere.

The most common reasons an Oldsmobile Alero is overheating are a coolant leak (water pump, radiator, hose etc.), the radiator fan, or a failed thermostat. Coolant leak (water pump, radiator, hose etc.)

Oldsmobile Alero Overheating - RepairPal

Videos on overheating. You probably have air in the system from when you replaced the thermostat. The coolant system needs 'burping' of air.

https://www.google.com/search?q=2000+Oldsmobile+Alero+running+ho

Burping

https://www.google.com/search?q=burping+coolant+system

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1. The radiator cap if working correctly it will release pressure in the system provided the cap you have is the correct pressure setting. If you are having a problem with pressure then replace the cap with a new radiator cap with the correct pressure setting. Do not use a cap with a pressure setting other than the original equipment pressure spec. So you do not go to the parts store and buy any radiator cap on the shelf that fits because they come with different pressure ratings and some of these will be totally unsuitable for your car.

2. If the pressure valve is stuck in the "old" cap the pressure release system will not work.

3. Overheating
Air pockets in the cooling system can definitely cause overheating and can retard coolant flow through the system. If you are draining the radiator to replace the coolant or replacing the radiator you need to follow the correct procedures for bleeding air out of the system for that particular engine after coolant refilling. Some engines have bleeder screws on the cooling system to assist in the air bleeding procedure and some don't.

There are various causes for overheating so don't assume it will necessarily be solved by bleeding any remaining air from the cooling system and replacing the radiator cap with one that works.

Other causes can be...........
1. Faulty cooling system thermostat. (Replace the Thermostat)
2. Faulty water pump, especially if the impellers have corroded away or have disintegrated in the case of those design genius water pumps with plastic impellers. (Replace the water pump)

3. Cooling fans not working and if so the cause needs to be tracked. Check that your fans are kicking in. If the engine is overheating the fans should be running because they will switch on when the coolant reaches a specific temp and well before the coolant gets excessively hot.

4. A partial blockage in the coolant passages inside the engine but not in the radiator if you have a new one. If the coolant is not changed at the required intervals(frequently the case with many owners) or is over diluted with water you can get a build up of debris. If products like stop leak have been used in the system this can create similar problems with partial blockages inside the engine coolant passages.

5. A compression leak into the cooling system.
If you have bled air from the system and have continuous air bubbles in the cooling system I would suspect a compression leak. In that event a basic leak down test will show if you have compression gasses leaking into the cooling system and from which cylinder(s). The spark plug is removed and compressed air is forced into the cylinder via the spark plug fitting and air bubbles will show up in the coolant of there is a leak into the cooling system.
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Have the problem with overheating addressed immediately. Running the engine with an overheat condition will cause expensive engine damage many times the cost of fixing the overheating issue.

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Are you sure the coolant level is full?
Did you "burp" the cooling system after you replaced the parts?

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

sounds like air in system ...
Leave the radiator cap off, turn the engine on and let it run until the radiator "burps": You will see the coolant level drop and may see or hear a large air bubble come to the top as the system burps.
Keep an eye on the temperature gauge throughout this process

Refill the radiator to the top and coolant reservoir as needed. Put the radiator cap back on. Note that if the engine runs hot after this procedure there may have been another pocket of air that "burped." Let the engine cool down and then add more coolant to both the radiator and the coolant reservoir.

Raise the car front end as high as possible with a floor jack, fill the coolant tank to the top, run the engine until it reaches just short of overheating, shut it down and run water over the radiator, this will burp the air out. Repeat as needed. Don't let the coolant recovery tank run dry during procedure.

clogged with old rad chunks
no white smoke

yes some systems have to be burped or the boil over can occur in the motor and cause head gasket issues..at 195k i think you should check the system for leaks and thermostat if it is opening at right tempatures or is slow..plus the vented cap on your radiator check with vacuum gauge if it holds about 12-14 psi before it vents...

48,000 miles or 48 months
Maintenance Service Schedule 2007 dodge
Change engine oil and engine oil filter
Rotate tires
Lubricate drivetrain / steering / suspension
grease fittings (if equipped)-except Powerwagon
Lubricate front drive shaft fitting
(2500 / 3500, 4X4 & Powewagon)
Lubricate tie rod end links - Powerwagon
Check automatic transmission fluid level
Check manual transmission fluid level
Check the coolant level, hoses and clamps
Inspect exhaust system
Inspect brake hoses and brake linings
Inspect the CV joints/U-joints (if equipped) and
front suspension components
Check spare tire for proper pressure & correct
stowage
Lubricate outer tie rod ends 2500/3500 4X4

51,000 miles or 51 months
Maintenance Service Schedule
Change engine oil and engine oil filter
Lubricate drivetrain / steering / suspension
grease fittings (if equipped)-except Powerwagon
Lubricate front drive shaft fitting
(2500/3500, 4X4 & Powerwagon)
Lubricate tie rod end links - Powerwagon
Check automatic transmission fluid level
Check manual transmission fluid level
Check the coolant level, hoses and clamps
Inspect exhaust system
Inspect brake hoses
Inspect the CV joints/U-joints (if equipped) and
front suspension components

It's possible that your transmission and filter has built-up a lot of gunk and deposits and is working overtime to get fluid to circulate through the transmission. The only other thing that can normally be checked without taking the vehicle to a transmission expert is the fluid level. However, I can tell you that I own a 2002 Blazer with a 4.3 L Vortec, and Blazers have always been notorious for having the transmissions go out on them if they are not checked and flushed on a routine basis (I suggest checking and/or flushing every 10-15K miles.). Hopefully this will help to shed some light on your problem. Have a great day!

Who did the replacement of the parts? Was it done at a shop or at home? Do you know if the cooling system was "burped" after the parts were installed and the coolant was refilled? If you're not sure, burp the radiator. This is easy to do. Jack up the vehicle so that the thermostat is angled upward. Start the car and let it idle until it's 3/4 of the way to overheating, then shut it off and allow it to cool down somewhat. Then pop the cap, let the coolant drain down, and refill it. Restart the vehicle and repeat the process, until the coolant level doesn't drop anymore.

What you're doing is this - anytime the cooling system is opened up, especially when the fluid is drained and parts are replaced, air gets into the system. When you reassemble and refill with coolant, you trap air bubbles in the system. Since the system is sealed, it operates under pressure. As the car runs, the coolant and the air bubbles are circulated. The bubbles get caught behind the thermostat (if you have it angled upward) and keep it from opening. This causes the engine to heat up to the point of overheating. You want to allow it to get about 3/4 of the way to an overheat so that you know the air bubbles are blocking the thermostat. Shutting down the car stops it from heating up to the point of damage, and allows the system time to cool off so that when you pop the cap, you don't get an explosion of coolant in your face. Once it's cool enough to open the system, you open it and release the pressure. This allows the thermostat to open and bleed the bubbles upward to the open cap, where they "burp" into the air. The space they took up fills with coolant, which is why your coolant level drains down. You top it off and repeat to make sure that all the bubbles are out. You'll know you're in good shape when you let it run and it gets to operating temperature and doesn't overheat anymore. Let it cool that final time, open the cap, and since you have no air pockets left in the system, nothing will burp out and your coolant level won't decrease. Then you should be good to go - put the cap back on and drive away happy.