alright, replaced the water pump on my S10 Blazer winter car (4.3L), and now the thing runs hot, around 220 to 240 according to the guage. the temp jumps around. We had to remove the radiator to get the pump out.

 

check thermostat, its a very common part to go to hell, plus its a very cheap fix if thats the problem. also it could be your radiator cap or freeze plugs, good luck man

 

If your cap is old that could very well be the problem as well. Do you have any way to check the factory gague? Also check your hoses, tough to say not being there, but good luck.

 

You may have a air lock in the system too. Try taking it for a little drive with the rad cap half off. YOu know...there are two catches on the cap just tighten it to the first one and goe for a ride, if there is a air lock this may help to get it out. HTH
Keiran

 

Install a new thermostat, just to be sure. Verify the cooling system if completely full(no air pockets). Check for proper fan operation--at those temps it should be blowing full force(loud roar if you rev it at all). If the fan clutch is very old, it's good idea to replace it when you change the pump. Of course, this is all assuming the temp guage is fairly accurate and you are running hotter than you need to be, and you are using a mechanical fan. FYI, what year are we talking about?

 

'89, and yes, unfortunatley, it is a mechanical fan. I've got no way to check the accuracy of the guage, but it ran a little below what was indicated to 210 before, and now above that, perhaps 220 - 240--way too hot.
Tryed cruizin kaz's idea about the radiator cap--no luck. I heard the roar, fgan is workin'. I'll try to throw on a new thermostat today if i get time. I had thought about that originally, since running the heater full force in Park makes no difference in temp at all, but I didn't want to replace it because that one is like 3-4 months old.
Thanks alot guys!

 

yes thermostats can go to hell even after a week, i went through 3 in a week cuz i got them from autozone, do yourself a favor and buy it from napa, autozones stuff is junk imo

 

Also, how clean is the radiator? With the grill set-up you have, the radiator takes on alot of trash. I have to clean mine a couple times a year--usually full of bugs, grass/weeds, other trash items.

 

Put the radiator back in.

 

Why did you have to take out the radiator anyway? Don't need to pull the radiator to put in a water pump in that vehicle.

 

We were too drunk
no really, i have no idea why we didn't think to take the fan off while the belt was still on, but we couldn't get the water pump off without removing the radiator. The thing came off really easily, but, of course, was a pain in my a** to put back in.

 

Does the new waterpump impeller rotate in the same direction as the old waterpump impeller? Serpentine waterpumps and V-Belt waterpumps rotate in opposite directions.