What is the effect of removing the thermostat?

On a cold engine, remove radiator cap, where applicable, is there coolant in the radiator? Usually the reservoir has cold and hot coolant levels marked on it. If it got too hot that reservoir would fill up in a hurry. When it got hot, what was the temp reading in degrees F? When it got hot, was the radiator fan running?
If your thinking thermostat, the engine side of upper radiator hose, should go to thermostat housing. Have to remove thermostat housing to get at thermostat.
Any applicable trouble codes? Some of the national brand auto stores will check po codes for free or use an obd2 code reader to check codes, yourself. There could be other issues, coolant temp sensor, gasket problem--if combustion gases in the coolant.

any time you omit the thermostat the heater wont work but the engine will operate at a cooler temp. I live in a hot climate year round and we southerners leave out the tstats on older jalopy.

Remove thermostat and run engine

The thermostat not only allows the normal heat cycle but it also allows the coolant to be able to cool itself before getting returned to the engine block.. If you remove the thermostat then you are not giving the coolant enough time to cool itself before going back into the motor. This will actually make the vehicle run hotter then cooler. I would recommend looking into the lowest temp thermostat available for your vehicle and look for an additive to help cool better..

Holts Wondarweld
Flush engine.
EXTERNAL CRACKS
1 Run engine until hot,drain off enough coolant to remove thermostat.
2 Remove thermostat.
3 Mix contents of can thoughoughly! and pour contents into thermostat opening.
4 Replace thermostat cover.& fill radiator with hot water,replace radiator cap.
5 Run engine at a fast idle for 15 mins,dont allow to boil.Top up if necessary.
6 Leave Wondarweld in system for 2-3 days then drain off,flush system replace thermostat and refill.
HAIRLINE CRACKS
1 MIX thoroughly and pour into cold engine (radiator if it has a cap)
2 Run engine until hot.
3 Allow engine to cool then run again until hot.
4 Follow procedure 6 above.
INTERNAL CRACKS
1 Follow external crack instructions except after pouring Wondarweld into engine remove spark plug from
affected cylinder and run engine for 20 mins. If more than one cylinder affected run for 5 minute intervals.
2 Allow engine to cool then drain cooling system and refill with clean water.
3 Drain sump & flush,refill with fresh oil.
Note:- 1/2 pint of Wondarweld for every 6 pints of water,DO NOT add antifreeze for at least 3 days after process.

the sending unit will not affect heat but if its broken it will effect the fuel control by giving computer false info, i dont think theres a problem with the temp unit, i think the thermostant is bad and is stuck open or you are very low on coolant, if the thermostat was stuck open then you would get some heat not very hot and would take a long time to get heat. i would start by replacing the thermostat, it is very important to bleed air from system after coolant change or thermostat replacing, after filling run engine until fan turns on , let cool some to release preasure then remove cap start engine and top off, drive for 15min then park let cool and recheck coolant, hope this helps,

yes, engine is more efficient when warm. Thermostat gets engine warm much faster.

REMOVAL & INSTALLATION
Gasoline Engines
CAUTION
Never open, service or drain the radiator or
cooling system when hot; serious burns can occur from the steam and hot coolant.
Also, when draining engine coolant, keep in mind that cats and dogs are
attracted to ethylene glycol antifreeze and could drink any that is left in an
uncovered container or in puddles on the ground. This will prove fatal in
sufficient quantities. Always drain coolant into a sealable container. Coolant
should be reused unless it is contaminated or is several years old.

1. Drain the radiator until the coolant is below the thermostat level (below
   the level of the intake manifold).
   
2. Remove the water outlet elbow assembly from the engine. Remove the
   thermostat from the engine, or, on the 4.8L, from inside the adapter elbow.
   To install:
   
   
3. Clean the gasket surfaces on the water outlet elbow and the intake manifold.
   Use a new gasket when installing the elbow to the manifold.
   
4. Install the new thermostat making sure the spring side is inserted into the
   engine, or, on the 4.8L, downward into the thermostat housing. Tighten the
   thermostat housing bolts to 20 ft. lbs. (28 Nm). On the 4.3L, 5.0L, 5.7L tighten
   the studs to 21 ft. lbs. (28 Nm). On the 7.4L tighten the bolts to 27 ft. lbs.
   (37 Nm).
   
5. Refill the cooling system. Start the engine and check for leaks.
   
   
   
   
   
   Fig. 1: Remove the thermostat housing bolts
   
   
   
   
   
   
   
   Fig. 2: Remove the thermostat housing from the engine
   
   
   
   
   
   
   
   Fig. 3: Remove the thermostat from the housing
   
   
   
   
   
   
   
   Fig. 4: Thermostat housing - 4.3L engines
   
   
   
   
   
   
   
   Fig. 5: Thermostat housing - 4.8L engines
   
   
   
   
   
   
   
   Fig. 6: Thermostat housing - 5.0L and 5.7L engines
   
   
   
   
   
   
   
   Fig. 7: Thermostat housing - 7.4L engines, R/V series
   
   
   
   
   
   
   
   Fig. 8: Thermostat housing - 7.4L engines C/K series
   
   

Diesel Engines
1988-95 MODELS

1. Remove the upper fan shroud.
   
2. Drain the cooling system to a point below the thermostat.
   
   
   
   
   
   Fig. 9: Thermostat housing - 6.2L engines, R/V series
   
   
   
   
   
   
   
   Fig. 10: Thermostat housing - 6.2L and 6.5L diesel engines -
   1988-95 C/K series
   
   
   
   
   
3. Remove the engine oil dipstick tube brace and the oil fill brace.
   
4. Remove the upper radiator hose.
   
5. Remove the water outlet.
   
6. Remove the thermostat and gasket.
   
7. Installation is the reverse of removal.
   
8. Use a new gasket coated with sealer, Make sure that the spring end of the
   thermostat is in the engine. Tighten the bolts to 35 ft. lbs. (47 Nm) on 1988-91
   models and 31 ft. lbs. (42 Nm) on 1992-95 models.

1996-98 MODELS

1. Drain the cooling system to a point below the thermostat.
   
2. Disconnect the upper radiator (inlet) hose from the thermostat outlet.
   
3. Ufasten the thermostat housing bolt and stud, then remove the housing.
   
4. Remove the gasket and the thermostat.
   
5. Clean any remaining gasket from the thermostat hosing mating surfaces.
   
   
   
   
   
   Fig. 11: Exploded view of the thermostat assembly components
   1996-98 diesel engines
   
   
   To install:
   
   
6. Place the thermostat into position in the housing, then install the gasket.
   
7. Install the thermostat housing, the bolt and the stud. Tighten the bolt and
   stud to 31 ft. lbs. (42 Nm).
   
8. Attach the upper radiator (inlet) hose to the thermostat outlet.
   
9. Fill the cooling system.
   
10. Start the engine with the radiator cap still removed, until the upper
    radiator hose is hot (this means the thermostat is open).
    
11. With the engine idling, add coolant until the coolant level reaches the
    bottom of the filler neck.
    
12. Instal the radiator cap making sure the arrows line up with the overflow
    tube and check for coolant leaks.

hi.. your coolant temp sensor may be getting a bad reading, it also opperates as a compensator so it may effect the power of the vehicle.. check that the engine is actualy hot when it says and your car will probably run alot better if you change it anyway..

Hi and welcome to FixYa,

Offhand, your described condition indicates a sticking thermostat, that is there is considerable delay before the thermostat opens. It is also possible that there is some restriction wherein the thermostat is not opening completely when the triggering temperature has been reached. As a test and to confirm, you could try temporarily removing the thermostat and operate the engine without one; observe temperature. The side effect of this test is that it would take some time to warm-up the engine, but operationally should not cause anything untoward. Of course, care has to be exercised that the gasket would still be intact.

Good luck and thank you for using FixYa.