I got a 2003 buick lesabre, I recently put in a radiator, water pump, heads. head gasket, 02 sensors, now my check engine light came back on an code reading p0463 (fuel level sending unit condition an p1181 (max adaptive an long term shift.i also have a small transmission leak plus my transmission fluid holder is lose... I need help I keep utting money in parts an larbor, I need answers....

Check coolant level.

There are a number of possibilities. Does the car overheat? It can be a blown head gasket. To check this, open the radiator cap (not the plastic filler bottle, I mean the metal cap on the radiator itself).
Put your nose close to the opening and smell the water. If it smells of exhaust gas, you have a blown head gasket.
Another check is to pull out the dipstick and have a look at the colour of the oil in the sump. If it has a grey colour, you have a blown head gasket.
The first place to look however is check on the floor after you've driven the car for a while, and see if you can see water dripping to the floor, or if you open the hood immediately after a longish drive, check for steam which could indicate a bad head gasket that did not blow into the water chamber per se.
Steam from a hot engine will also indicate leaking radiator hoses or a leaking water pump.
If you suspect the water pump, again, open the metal radiator cap and fill the radiator to the top. Let the engine idle until it is hot, then rev it a bit. If the water pump is working, you will see the water inside the radiator circulating. Just make sure the engine is hot, else the thermostat will prevent the water from circulating.
An extra bit of information, if you can see the water circulating and also notice bubbles in the water, it is an indication of a leaking head gasket.

Take it back to who ever is guessing what the issue is and tell them to fix the intake gasket. IT was not installed correctly or torqued right. Depending on the mileage you may get a free catalytic converter. They are rated for 10 years. Contact a dealer about it. But if you had a blown head gasket and coolant got into the exhaust, the cat should be replaced. Silicon additives in coolant ruin catalytic converters

Check to see if your fan is coming on. if it is then check the middle of your radiator if it is cool while the outside is hot you have plugged radiator

Was the oil changed? Has the low pressure been verified with a mechanical test gauge at the oil pressure sending unit pressure port? Do that 1st before assuming the pressure is low.

OVERHEATING CAN BE CAUSE BY MANY THINGS LIKE FAULTY THERMOSTAT AND FAULTY RADIATOR PRESSURE CAP,TOO MUCH WATER IN COOLANT SYSTEM NEED 50 / 50 WATER AND ANTIFREEZE.LOOK FOR WATER PUMP WEEP HOLE LEAK, IF COOLANT LEAKING OUT WEEP HOLE WATER PUMP BAD NEED REPLACING.CHECK FOR LOW COOLANT LEVEL, YOUR RADIATOR OVERFLOW JUG SHOULD HAVE COOLANT AT THE FULL COLD MARK IF NOT KEEP ADDING COOLANT INTO COOLANT OVERFLOW JUG UNTIL COOLANT STOP DROPPING AND FULL COLD MARK, IF OVERFLOW COOLANT JUG WAS EMPTY RADIATOR IS LOW ON COOLANT.WHICH CAUSE AIR IN COOLANT SYSTEM KEEPING THE ENGINE COOLANT TEMPERATURE SENSOR FROM BEING SUBMERGE IN HOT COOLANT WHICH TURN ON THE COOLANT FANS.WHEN ENGINE COOLANT TEMPERATURE GET CERTAIN SET TEMPERATURE LIKE 190 DEGREES THE PCM AND COOLANT SENSOR WILL TURN ON COOLANT FANS, IF VECHICLE OVERHEATING COOLANT FANS NOT WORKING EITHER YOU HAVE FAULTY ENGINE COOLANT TEMPERATURE SENSOR CHECK COOLANT FANS FUSE AND RELAYS. YOU CAN CODE SCAN CAR TO SEE IF YOU HAVE FAULTY PCM, FAULTY ENGINE COOLANT TEMPERATURE SENSOR OR FAULTY COOLANT FAN RELAY.IF COOLANT FAN AND ENGINE COOLANT TEMPERATURE SENSOR OKAY,YOU HAVE CORRECT COOLANT LEVEL IN COOLANT SYSTEM, THERMOSTAT AND RADIATOR PRESSURE CAP BEEN REPLACED, YOU COULD HAVE BLOWN HEAD GASKET CHECK ENGINE OIL LOOKS LIKE MILK SHAKE HEAD GASKET BLOWED ALSO WHEN HEAD GASKET BLOWED YOU CAN DRIVE CAR SHORT DISTANCE START OVERHEATING AND YOU LOOSE ENGINE POWER SUSPECT BLOWED HEAD GASKET.

Hello robtui: My name is Roger and I will help with your problem. The engine cranks over and does not start? Collant is belched out of the radiator? Problem is a warped head(s).Blown head gasket or cracked head. Remove the spark plugs fill the coolant system and you should see coolant fill and run out a spark plug hole. The engine should of had a miss before this happend. You could also do a compression test instead of filling the radiator and looking for coolant to run out. Either way you will find a cylinder compression leaking to the coolant passage. Should you need further help please just ask. Please rate the answer. Thank You for using Fix Ya. Roger

Sounds like the intake gasket or even possibly the head gasket have gone south if everything else has been replaced. Internal engine leaks will cause engine to overheat very easily.

You have a head gasket blown,or a crack in one of the heads

The coolant that you are adding fills up to the top of radiator, then slowly drains down through engine block and water pump, You will have to fill radiator completely about 2 times for it to stay full for good.