My 01 deville wont stop overheating we replaced waterpump thermostat waterpump cover and all the gaskets wat else could it b

You've covered everything on the outside of the engine now you need to look for a bad head gasket or cracked head. The best way is removal, because anything that you may have missed until the tear down is included in the gasket kit. I recommend you order the valve grinding gasket set before you tear it apart because the shop that rebuilds the head needs parts from the kit, this is usually not a big job. I hope this helps. Take Care.

you may have a air lock if you did all that work and it is overheating-thermostat ok?

If it is overheating, coolant coming out of tank, you may have a head gasket issue

I'd start with replacing thermostat (that's the most common fault) Other possibilities; waterpump,leaky hose, radiator cap (not holding pressure), fan belt broken. I'd inspect for belt & leaks - if good replace thermostat.

This car is hard to blow a head gasket but sounds like you overheated it too the point the motor stopped running, you will need to find out first what the leak was and repair it and also replace the thermostat due to overheating it, then fill with coolant and run the motor, if you have an overheating problem then have a block test done to see if the gasket let go.i ve worked on many that were overheated and they were ok, they just needed a thermostat and a waterpump that leaked or the impeller was rotted away, hope this helps.

BLOWN HEAD GASKET IS THE PROBLEM CANT PATCH UP WITH STOP LEAK PRODUCTS WHICH WILL STOP RADIATOR CORES AND HEATER CORES UP PROMOTING OVERHEATING.HEADGASKET LEAKS HAS TO BE FIX.IT GOING TO COST SOME MONEY.

A head gasket leak is usually indicated (among other things) by continous overheating of the motor, and subsequent loss of coolant.
It can also be indicated by the presence of engine combustion gas bubbles in the coolant resevoir.
Ensure the coolant system has no external leaks, such as faulty hose/s, radiator etc.

Ensure motor tune or other motor mechanical condition is not the cause of overheating.
I assume the motor is actually running hot.

Check cooling fans are operating ok (as necessary when car warms up):- if not check
1) fuse,
2) relay operation,
3) heat sensor switch.

Check/replace the thermostat,
Check the coolant pressure cap is serviceable & of correct rating,
Ensure cooling system is correctly filled, bleed off any airlocks as necessary when re-filling,
Ensure radiator hose on suction side of waterpump is not collapsing at engine revs above idle (due softening),
If the motor has been severely overheated, the head gasket could be blown - look for combustion gas bubbles in the coolant resevoir.

I assume motor tune or other mechanical condition is not causing the problem.
Yes, the thermostat is a common cause of overheating - replace the thermostat.
Also:-
Check operation of the radiator cooling fans is ok.
Check the coolant pressure cap is serviceable & of correct rating,
Ensure cooling system is correctly filled, bleed off any airlocks as necessary,
Ensure radiator hose on suction side of waterpump is not collapsing at engine revs above idle (due softening),
Check radiator cooling core is not blocked internally or externally.
If the motor has been severely overheated, the head gasket could be blown - look for combustion gas bubbles in the coolant resevoir.

Sounds like an overheating problem, best to get it checked, maybe thermostat stuck closed, pluged radiator, head gasget, cracked head.

99 cadillac deville overheating put in new radiator,thermostat,waterpump. it stays cool at idle for a hour running.drivin about 15-30 minutes it overheats. is not using hardly any coolant to speak of.