I have 1994 S10 with the 2.2. The problem is the heater does not work. The relevant information to my situation is as follows:

1. I pulled the hoses to the heater core and flushed it out completely.

2. The entire coolant system has been flushed so there is no blockage to the flow of coolant.

3. When the engine is running and the hoses to the heater core are removed, there is no flow of coolant coming out of them at all. It seems to me that with the engine running warm and the thermostat open, the pressure of the coolant system would send coolant out of the hose going into the heater core. I even tried removing the thermostat and still no dice.

4. If I disconnect the hose leading into the radiator and the engine is running and the thermostat is open, there are intermittent belches of water that come through the hose, not a steady stream like I would expect. Note that the radiator is full of coolant.

5. While driving the vehicle, the temperature gauge settles at about 3/4 the way up, probably about 230 degrees and stays there.

Is it possible that the water pump is in need of replacement? Or is it possibly something else? If I am leaving out any relevant info, please let me know. Thanks in advance. By the way, this is my first s10 and I bought it a few days ago for 800 bucks.

The fitting that the hoseattaches to might be plugged. I believe it attaches at the thermostat housing. Also, if your removing the supply hose at the core inlet, there may be a flap inside of the hose, try some new hoses.

I have 1994 S10 with the 2.2. The problem is the heater does not work. The relevant information to my situation is as follows:

1. I pulled the hoses to the heater core and flushed it out completely.

2. The entire coolant system has been flushed so there is no blockage to the flow of coolant.

3. When the engine is running and the hoses to the heater core are removed, there is no flow of coolant coming out of them at all. It seems to me that with the engine running warm and the thermostat open, the pressure of the coolant system would send coolant out of the hose going into the heater core. I even tried removing the thermostat and still no dice.

4. If I disconnect the hose leading into the radiator and the engine is running and the thermostat is open, there are intermittent belches of water that come through the hose, not a steady stream like I would expect. Note that the radiator is full of coolant.

5. While driving the vehicle, the temperature gauge settles at about 3/4 the way up, probably about 230 degrees and stays there.

Is it possible that the water pump is in need of replacement? Or is it possibly something else? If I am leaving out any relevant info, please let me know. Thanks in advance. By the way, this is my first s10 and I bought it a few days ago for 800 bucks.

Jesus, stop driving it like this. You can't drive a vehicle that hot, you are only doing damage.

First of all, did you completely refill the rad?

Did you replace the Rad cap, if not, do it, it will fail, it did on my 1995.

Go out in the morning and open the rad cap and tell me if the fluid is right up to the top?

I am taking your advice and am not driving the truck until the problem is resolved. I did fill it with radiator fluid last night and it is still full today. I have not replaced the radiator cap but I am going to do so today. Incidentally, I don't know why I said its a 94, its actually a 95 too. I really don't think its the hoses because not only would fluid not flow through the small heater core ones, it wouldn't even come out of the large hose that goes into the radiator with the engine running. I am sure there is no blockage in the system because I ran a water hose through it and it gushed out. Therefore leading me to believe its the water pump. Thanks for the replies.

Did you add coolant to the reservoir or to the radiator? I've found that adding to the reservoir does not necessarily help.

I actually added it to both.

Learn to answer people's questions:

First of all, did you completely refill the rad?

Did you replace the Rad cap, if not, do it, it will fail, it did on my 1995.

Go out in the morning and open the rad cap and tell me if the fluid is right up to the top?

Thanks for the help and the suggestions, BlazerLT. I pulled the water pump off and it was missing the impellers. So, obviously, it was the water pump primarily. Now, I am concerned there may be the remnants of the impellers in my engine block and radiator. Any suggestions for their removal? BTW, BlazerLT, I did completely fill the rad and reservoir, replaced the cap per your suggestion and checked it this morning. It was full to the top after sitting all night.

Excellent, then everything should be ok withthe levels then.

As to the blades in the cooling system, you better check that out and check for them where they go into the engine and remove the intake hose going to the heater and chek for the blades blocking the hose.

How many blades were missing?

All of them. Its amazing the engine didn't overheat and die. But the guy I bought it off of said he has been driving it for several months after it started "overheating". I flushed the block out with a water hose and replaced all of the coolant system hoses. Some broken pieces of metal came out of the block. I put on a new water pump and everything seems to be okay now. The heater works and the temp actually sits a little too low. Anyway, thanks for the help.

Replace the thermostat.