Hi,

I have a 1992 Blazer 4.3 V6 Vin "W". It started overheating last week so i replaced the thermostat. The thermostat was stuck open and a bit rusty. After replacing the thermostat it is still overheating so i assume its the water pump now, but when i checked around the thermostat i noticed a small leak. Doesn't that mean the water pump works to make enough pressure to cause the little leak? could it be a faulty thermostat or something else...

Just want to know for sure if its the water pump before i switch it out, don't really got much extra cash to replace things that don't really need to be replaced.


Thanks,

Colin

 

Well first of all a thermostat stuck open will not cause overheating. I would say you have radiator problems since you mentioned rust. Radiator probably needs a good cleaning or replacing. Your leak around the thermostat housing is probably just a gasket problem. I would imagine the heater core is rusty as well but that is a major knuckle buster.

 

I did a flush when i replaced the thermostat that's why i'm leaning towards it being the water pump...

The truck starts fine, runs good until it reaches running temp then it will struggle and just keep climbing in temp. i also noticed the top radiator hose doesn't feel like anything is making it there. I also get a check engine light after about 5-10min of idling and no heat inside the cab at all

how can i check for sure that it is the water pump?

 

No heat in the cab means your heater core is either plugged or has a lot of air trapped in it.

You need to backflush the heater core and then do several bleeding cycles on the radiator with the front right wheel a little higher than everything else.

 

Yeah I would say you are definitely plugged up. Depending on how long you intend to keep the truck, I would try to backflush that heater core with a water hose. Be careful not too much pressure because that rust may be eating through it and it may burst. I put one in mine and it is NO fun and I will never put another in. You can get a new radiator for less than $150-New or cheaper to get a radiator shop to clean the old one or go to a junk yard. If you are doing all this I would also replace the pump and hoses.......But that is just me. It is your decision...Is this truck worth the investment?
*COMBINING CONSECUTIVE POSTS*
Oh get the code checked for the check engine light with a OBD 1 reader or research here for a way to do it with a paper clip. More than likely I guess it is the temperature sensor.

 

Oh get the code checked for the check engine light with a OBD 1 reader or research here for a way to do it with a paper clip. More than likely I guess it is the temperature sensor.

 

Just replaced the water pump in my blazer and by what you are describing yours does not sound like the water pump
When the water pump goes bad there is a plug at the bottom that releases pressure so it doesn't back up into your system
So when it goes you will basically be dumping antifreeze out of the water pump.

I would check to see if the water pump is wet undernieth and then check the radiator hose for cracks and leaks.

Water pump is fairly inexpensive but taking apart the fan and fan clutch is a little tight quatered.

 

well since it could be a number of things i think i'm going to take it over to a shop for them to find out whats wrong then go from there.

We just got about 8 inches of snow here and due to this problem i have been driving around my jetta vr6 that is lowered on coilovers and has 17" rims with summer tires....it sucks [:@]

 

Just got it back from the shop on friday. They replaced the Intake Manifold gasket and some other gaskets and threw in a new thermostat and flushed the system. It was still overheating, but not as quickly as before. So they told me the radiator is most likely plugged or bad so replace it myself today and still the engine overheats. I think i got all the air pockets out of the system and i'm now not sure what to do next.... Also the temp gauge seems to be acting up as it will show the engine overheating instantly when i know the engine is cold, but was working fine earlier in the day... Any ideas?

 

All that's left is the water pump and heater core. You could get something from a local parts store to bypass the heater core for the time being. Changing the heater core isn't that bad to do.