Engine Cooling problem
1989 Chevy Blazer 6 cyl Four Wheel Drive Automatic 138000 miles
I recently purchased an '89 chevy s-blazer with the 4.3 L V-6. I live in a high elavation colder climate and as it has gotten colder I noticed the truck wasn't putting out very much heat. So the first thing I thought was to replace the thermostat. When going to replace it I found there wasn't one in there. When I put one in, the engine will overheat. To make a long story shorter, I ended up replacing the radiator cap, upper and lower hoses, radiator ( new ), and water pump. After none of this stopped the overheating, I tested the thermostat and found that two I had puchased didn't open but the third did. This didn't stop the overheating. I took the water pump apart to check rotation to the pulley and found it is turning in the wrong direction. This is the pump direction ( reverse ) that is used through '95. I tried to use a newer pump ( clockwise) but It is to different to mount. I'm not sure what if any modifications were done to this engine. After $200.00 + I'm running out of ideas as to why the pump is running the wrong direction. Living in the high country I would like to have heat without overheating the engine. Note: The cooling system was also back flushed before the new radiator.
The truck will run cool without the thermostat, as it was when I bought it, but this is with low heat, poor milelage, less passing and climbing power, etc.
Bottom line: Why doesn't engine rotation corrispond to the water pump.
That 4.3 should have a reverse rotation pump on it if it has the serpentine belt drive. If it has the older V belt drive then it uses a standard rotation pump.
November, 11, 2008 AT 6:24 PM
This 4.3 has the serpentine belt. Is there a standard rotation pump that will fit this year?
November, 11, 2008 AT 9:11 PM
Unless the belt is routed the wrong way for some reason it should be a reverse rotation pump. The pump is driven off the back of the belt and rotates the reverse of the engine. It should rotate the same direction as the fan draws air through the radiator.
From what it sounds like I suspect the problem with overheating is caused by something else. You did install the thermostat with the element down? Did you burp all the air out of the system after the work? I usually park so the right front is up on a bank. Then fill the engine slowly. Then with the cap off start the engine and let it warm up. Now let it cool off and top it off. You may need to do that a couple times to get all the air out of the heater core and block.
Here is a belt diagram
November, 12, 2008 AT 7:05 PM
The belt is routed as in the diagram, but the pulley and the fan turn clockwise ( as stated from the drivers seat ) and the water pump is reverse. I know this because I've had two new pumps apart to check there direction and they are reverse to the pulley direction. If I can get the water pump to work right and still have a problem, then maybe I didn't burp the system good enough or something. I just can't figure out what was done to this truck to run the pulley clockwise when it should be counterclockwise.
November, 12, 2008 AT 9:01 PM
Where are you buying your pumps from and what are you asking for when you get them. I ask because if you simply say it's for an 89 Blazer they will be giving you a standard rotation pump.
You need to specify that this is a reverse rotation pump for an S10 Blazer.
Advance part number is WP715 or WP715HD Both are new reverse rotation pumps, the HD is heavy duty.