1994 BuickRegal...low coolant light came on then the engine gauge went into the red area. Would these symptoms be that of a thermostat or plug on the fan?

New thermostat, installed, saw, new coolant made a little mess filling reservoir, (normal) checked fan fuse for some reason, and condenser fan fuse (xxx ?:), and temp guage, is slightly lower on gauge (than normal?) (disconnected xxxx? quit? a bit? to get to thermosta?.t no dash warning lights have a feeling I popped a relay.

Answer:

ok, you did a coolant service with STAT,

and it failed.

tell us what works right and wrong, symptoms only.

over heating? parked, (fan never comes on)? as it hits 225F?

under heating? ( fan stuck on , up North can cause huge cold engine)

dash gauge stuck low. (thermostat wrong heat range 180f is best. see FSM for spec. on this temp. spec..

Dash guage varies.? oddly (air in system)?

Dash gauge too high.? (Stat put in upside-down or bleed hole (jiggle) not UP side. higher side of mount , trapping air.)

Does something wrong happen only driving?

leaks?

does cap on rad hold 12-14psi pressure, hot.?

if car has fan belts, are they tight? (for sure water pump does)

Tough to say without a fault code read out. There was a nice service information bulletin about your instrument lighting up like a christmas tree that lead to an engine harness. Your thermostat could also do that. As long as your check engine light NOT on and your coolant level is good, then you should be ok to drive on it. While a jammed thermostat will sometimes not set a fault, it could over heat your engine. With the vehicle COLD, try opening the expansion tank then starting the vehicle, if you see a small jet of coolant then your water pump is good.

Yes, the temperature gauge should normally stop in the middle, between the cold and hot points on the gauge. When the engine is cold the thermostat will be closed and will keep recirculating the coolant in the engine block until it warms up sufficiently. Then the temperature of the warm coolant will cause the thermostat to open the channel to the radiator to get rid of excess heat, which should stop the coolant from over heating. So the effect of the thermostat keeps the coolant at a fairly stable temperature. When the coolant runs low, it can't transfer enough heat to the radiator and the coolant and engine then over heats. Watch for radiator leaks under your car after you have been driving it. If the coolant goes low again fairly quickly you could have a leak in a hose or the radiator itself.

To start with, you are talking about the temp gauge. The thermostat is in the engine.
The coolant system could be low or have air pockets and still look full.
First thing I would check is the cooling fan, then the coolant level.

Hi,

The overheating and lack of cabin heat both point to a failed engine thermostat which would be stuck closed. At the warm up stage, the coolant stays in the engine block to bring the engine to efficient operating temperature, then it opens and circulates the coolant through the radiator and heat core. If the thermostat is stuck closed, the engine will overheat, and coolant will never reach the heater core, and you will not get cabin heat.

Blinking oil light at idle which goes away during driving could be a low oil level, but may also be a drop in oil pressue. You could have a clogged oil fliter (at best) pickup tube, or a failing oil pump.

You are describing a slow coolant leak and the resultant no heat and blockoverheating symptoms. The no heat is because there is insufficient coolant to cycle through the heater core, and the chuggin you describe is the engine indicating serious overheating.
With engine cold, you must add water--not anti-freeze--to the radiator itself, until it reaches the top of the radiator, then start the engine. If you do not have a radiator cap in addition to the overflow bottle (some vehicles don't), you must still add water to the radiator, even if you have to bypass the overflow bottle hose to do it. Add water until no more will go into the radiator. Start engine, let idle until operating temperature is reached. Thermostat should open and a good bit of the water will "sink" into the depth of the radiator. If you have no radiator cap, observe the temperature guage. When it reaches normal operating temp, when the thermostat opens, the temp will drop briefly at first, and you will notice warm air from the heater/defroster.
Once engine is warm and known to be full of water, seal radiator cap and/or system, and let idle for 30 minutes. Use this time to locate the "mystery leak." They can be very hard to find, and some won't leak until after the engine is turned off. During this idle period, observe the vehicle exhaust from the tailpipe as well as looking for actual water leaks: sometimes a bad head gasket can be diagnosed this way; if the exhaust is white and thick like steam, and smells like anit-freeze, you have a more serious problem. It is possible that after the repeated overheating cycles you have endured you may now have both a "mystery leak" and a blown head gasket.
Once leak is located, your next step is to let engine cool completely, drain the water, fix the leak, and then and only then add new antifreeze of the proper rating and ratio recommended by Chevy for your vehicle.
Anytime you drain a cooling system and refill it, it is necessary to check the overflow bottle at least 3 times in the first week after repair to ensure that you have the proper coolant level, and have not either missed another leak or not correctly repaired one. You MUST check it before you drive the vehicle the second time after the first repair attempt because it is normal to need to add more coolant than you added initially after the repair because of air trapped in the cooling system that will only be expelled after the first start/stop heating cycle. If after 1 week of daily normal driving you have only added a little more coolant once, and there are no more problems, you can be very comfortable that you have fixed your car.

Could be the thermostat. I know nothing about cars but I noticed my 2000 Grand Prix temp gauge was not going to the normal level. My wife drives this car so I didn't notice it for a month or so. Eventually the Engine light came on. Took it to Autozone and the code came back as P0180... (1) low coolant (2) bad thermostat (3) enginge fuel temp sensor. They used a code reader that was about the size of an Ipod nano.

Coolant was okay, so took it to my mechanic. His netbook sized computer showed it was the Thermostat. He reset the codes and the temp guage went back to normal. Was short on $40 for the fix at the time, so I parked the car and promised to bring it back in 3 days. Went out and checked the car a day later at 25 degrees outside without starting the car... gauge still sitting at the normal level. No question it's the thermostat. That car will not be driven again until T.stat is fixed in 2 days.

There are two possiblities that come to mind. Low coolant level with a very big air bubble may not permit proper cooling (too much air in the cooling system so add more liquid) or the second thing could be that the thermostat is not the proper rating for your gauge to remain below the middle level. You should try replacing the thermostat with a 180 degree thermostat (yes again and make sure orientation of the thermostat is correct... not upside down) and if the NEW thermostat is "good" it will stay near the middle regardless of whether the AC is on or not. You should also carefully check for coolant leaks or a reservoir tank crack, a loose fitting radiator cap with a worn o-ring or anything that would keep the system from being pressurized since pressure and glycol are what prevents the water from boiling in the cooling system.

When your temperature gauge reaches "H' it may too late to prevent a major breakdown. Knowing the symptoms of an overheated car and how they occur may be the difference between being inconvenienced and incapacitated.
Identification:---Other than a low oil level or low oil pressure light, there is not a more significant part of a car's instrumentation than a rising temperature gauge or a glowing "Hot" light. These lights are really the only confirmation a driver has that his car is really overheating. It is the identification of the symptoms of an overheating car that enable the motorist to avert a badly damaged engine. Overheating is always a traumatic event for a car's engine, which makes the early identification of the symptom an important addition to the informed motorist's tool kit.
Stuck Thermostat:--The car's thermostat is a valve that controls coolant flow from the engine block to the radiator. When the engine is cold the thermostat remains closed so that the coolant can reach operating temperature quicker and also provide heat to the passenger's compartment. The thermostat has a spring on it that moves depending on coolant temperature causing the thermostat to open. Sometimes the thermostat fails to open thus restricting coolant flow to the radiator where it would be cooled down. This condition is often the cause of overheating. The symptoms of this cause would be a rising temperature gauge and possibly the loss of heat inside the car.
Restricted Radiator:---A car's radiator will have thousands of gallons of coolant passing through in its lifetime. Along with the coolant comes particulate matter in the form of corrosion breaking loose from various parts of the car's cooling system. These contaminates collect in the tubes of the radiator reducing its efficiency. Extensive "plugging" in the radiator will cause the car to overheat. The symptom of this condition would be a rising temperature gauge which goes up when you accelerate.
Coolant Loss:--A car's cooling system is a closed loop system. You are not supposed to lose coolant. Sufficient coolant loss will cause the engine to run hot because engine is heating less coolant to higher temperatures. The symptom of overheating induced by coolant loss would be a pool of coolant on the pavement when the leak is external. Steam under the hood as the lost coolant hits hot parts of the engine, or a rising temperature gauge in the case of a undetectable engine related leak. Of course, the gauge would also go up if the leaks were not detected. Deteriorated Water Pump:--Cars use a belt driven pump to push the water and coolant mixture through the cooling system. This part is called the water pump. Rarely the impeller that draws the coolant through the pump will rust away making it impossible to push any through the system. If this occurs the temperature gauge will climb and coolant will boil over in the radiator. Inoperable Fan:----Most cooling fans are electrically driven. Some are driven by fan belts. If a belt breaks or the electric supply to the fan is interrupted overheating may result. Electric fans are tuned on thermostatically when needed. When the car runs at idle for extended periods or the weather is extremely hot, a failed fan will cause overheating otherwise it serves as a standby assist to the rest of the cooling system. In stress conditions an inoperable fan will cause the temperature gauge to rise. This will help. Thanks please keep updated.please please do rate the solution positively .thank you for using fixya

The problem is your coolant level has gone too low check and top up when engine is cold, you will see the marks on the expansion bottle, if prob persists there may be an airlock in the heater radiator. keep an eye on coolant level or you will have cylinder head problems.