The blazer has over heated twice in a week. I noticed steam bubbling out of a hole on the top of the water pump behind the pulley. Is the water pump bad?

if you used some rad sealer the thermostat is probably bad, so it will be overheating, this will blow the head gasket. take the thermostat out and refit. without the it in, go for a drive, the temp should rise up and down. when you come back leave to cool down. and flush the system out with fresh water, and then replace with new thermostat, if no leaks top up with antifreeze and water, leave top off and run engine to get bubbles out of engine squeeze radiator pipes as warming up. and top up water as it goes below line. when all air is out and fan has come on to say its at full temp. leave to go cold. and top up if needed and put cap back on.

check the engine for where the water is leaking. I had an engine leaking at the back side and it was corroded
Welsh plugs in the engine. If it was the water pump water it would be leaking out the water pump. Check Hoses with engine hot . Also check exhaust pipe is not blowing steam out from a blown head gasket.

probably a bad water pump.. steam escaping from the small hole behind the pulley or around the gasket. before changing water pump though, search for exactly where the steam is coming from... could be just a worn hose.

Could be either. Try tightening the clamp on the hose. If still leaking, probably the pump. There is a hole on bottom of pump behind the pump pulley, called a "weep hole". If the pump's internal seal is bad, this hole will leak coolant. Can you get a piece of mirror situated right to view this area? Or if you see white stains on the pump behind the pulley, that could be coolant leak.

If you are seeing air bubbles, then the cooling system still has air pockets in it. Loosen the overflow cap and leave it that way for a few days while you drive.Keep the heater turned on at the max heat level. Roll a window down if necessary. Check and top up the overflow bucket daily and top up as necessary. The bubbles should disappear after a few days, then you can tighten the cap. This should also solve your no heat problem. Once the bubbles are gone you can tighten the cap.

If the problem doesn't fix itself in a week, you should have the car looked at for a possible bad head gasket, which would force air into the cooling system. Hope this helps.

try the thermostat, located on the top radiator hose. top side of engine. also does it steam?? does it lose water but no leak, does the heat blow hot? if your heat isnt hot and it steams and loses water you may have a cracked head or head gasket. if you have heat, doesnt lose water and doesnt steam it may also be your water pump. most pumps will leak visibly from the weep hole when running

You can buy or possibly rent a coolant system tester which pumps air into it to help locate leaks. Very simple to use. You just remove your radiator cap and replace it with the tester and pump it up to the PSI listed on your radiator cap and watch for leaks. I would pay close attention to the water pump and intake manifold gaskets. It could be something as simple as a loose radiator hose clamp. It is common for intake manifolds to leak and they expand when hot and contract when cool so the leak is more noticable after sitting. Look on top of the engine around your intake manifold and your heater hose for coolant or a chalky like residue which can form from coolant leaking. Your water pump has what is called a weep hole on it which will be located behind the pulley close to the shaft. You may need to use a mirror to see it. If coolant is leaking out of it the water pump will need replaced.

Their is a small hole in both timing wheel's with a treaded hole behind them in the engine turn the mark ot the bottom shaft to the top screw in two screws to both wheel's timing set. For more timing info search fixya as I have answered this question four times in the last two weeks and have gone to great detail with it. Cheer's

Look behind the pulley, there is a little hols called the weep hole. If water is coming from there it's the seal replacemrnt is necessary

I have an 05 TB. I have replaced the idler pulley twice in the three years I owned it. Cheap and quick fix. Call your dealer and get the part. Problem is that the part comes with the whole bracket. Take the pulley of the new part and put it on the existing bracket already on your vehicle. 30 minute fix.