I have a 99 2 door blazer and its been giving me some trouble lately, earlier this spring it was over heating a lot and all i could do at the time was to keep a couple extra jugs of water in the back of the vehicle when i left for work in the morning so i could make it home afterwards. to say I'm "not mechanically inclined" is an understatement.. however a buddy of mine had a look at it and said it was air locked cause the thermostat was sticking. he advised to just take the thermostat out entirely and run it with water. he said it would be fine like that for the summer but i would need to remember to get a new one put in before winter and replace the water with actual coolant before it got cold (I live in central Alberta so it gets pretty dam cold). he took it out for me and just as he said the vehicle was fine all summer, no issues.

Then about a month ago i went and got a new thermostat and stopped at the hardware store for coolant. walked up to a guy stocking shelves in an aisle in the automotive section and told him i was putting a new thermostat in my vehicle and needed coolant. he handed me a jug of what he was stocking the shelf with and said it was premixed but it would work fine. turns out it was plumbing coolant. I had no idea..

So i put the new thermostat in and added the plumbing coolant and it was fine for 5 or 6 days, then i was heading home from the store one evening and noticed a weird smell coming through the vents.. and the windshield started to fog up really badly. found out the next day from doing a bit of research online and talking to a couple people that what i put in the rad completely screwed the heater core.. so i bought a new one and decided to try replacing it myself. found some videos online with some helpful tips and with the help of a friend of mine managed to get it all put back together and back on the road.
(I also put in a new blower motor at the same time because the one in it was completely screwed.. I went all summer and part of last winter with no heat, no A/C, or fan at all.)
Everything went well for the most part and everything was working just fine for about 2 weeks or so. then 2 days ago it randomly over heated again.. I pulled over and got out of the vehicle to open the hood but when i shut the vehicle off there was a bunch of smoke/steam coming from under the hood. when i opened the hood the steam/smoke looked to be coming from somewhere in between the rad/fan and the front side of the motor but underneath it kind of.. it seems like there might be a leak in the lower hose that connects to the rad because when i squeeze it i can hear air escaping from somewhere. it doesn't seem like it has a blown head gasket cause it definitely the coolant isn't getting into the oil at all.
do i need a new water pump? or maybe just hoses for the coolant system? any advice or suggestions would be appreciated alot.. thanks in advance..

 

Sounds like a water pump from the position you described. They have a weep hole directly underneath the shaft going back through it, and this is where water comes out when the pump goes bad.

Good luck!

 

Sounds like water pump to me as well. I changed mine out last summer. It was to bad of a job when getting the correct tools you will need. The fan clutch tool and correct fan clutch wrench make it a breeze. You can rent the tools at oreillys. The water pump comes with paper gaskets and they suck. I trashed them and used sealant instead. Going strong a year later no issues. Also changed out thermostat while I was at it. It took about 5 hours and if I had to do it again I could do it in half the time. I'm not very mechanically inclined as I do home remodeling.

Also question for ya what is plumbing coolant!?? Always use DEXOS coolant you know it's right if it's orange. They make a universal green coolant but it's not recommended and it's the same price as the right stuff.

 

Plumbing coolant is meant for a motor home to "winterproof" it for use in cold weather apparently... i guess it can be used in your boat or in a cottage as well. its to keep your pipes from freezing and bursting when it gets freezing cold.. not intended for an engine (as I've learned the hard way).. lol

 

How can I make sure its the water pump? Unfortunately funds are pretty limited lately as I'm currently on WCB and still healing from falling off a roof at work 4 1/2 meters (15 feet) onto my head on a concrete driveway back in July.. I don't want to go buy a new water pump and take the time to install it just to find out it was something else all along..

 

To test for water leaks, you often can rent or borrow a pressure tester from a local autoparts stores. These consist of a hand pump with pressure gauge and adapters for attaching to where the radiator cap goes.

Attach the tester to your cold radiator and pump it up to the same value as the radiator cap. Then look for a pressure drop and leaks.

 

What Christine said. You can also use florescent dye and a black light.

George