98 Blazer Heat Problems

hello. new to the forum here. i have a 98 blazer and recently my heater is doing nothing but blowing cold air, which is just great during february in boston!!! anyway, i recently had 2 leaks fixed (new gasket and freeze plug) so i no longer have any leaks but it seems right after i had those fixed my heater just went cold. the fan/blower is fine, it's just that the air is coming out like A/C. i also noticed that for a while, if i revved the motor extremely high, the heat seemed like it wanted to kick in but once i took my foot off the gas, it went right back to cold. also, i thought it might be a thermostat, but the temp. guage is reading normal. any ideas would help. thanx.

Go pick up a prestone flush kit from wal-mart or any local auto parts place, install it and flush the core. The fluid causes all sorts of gunk to build up in the core. My jimmy was an 00 and the core clogged in 03 with 60k on it. Installed the back flush, flushed it, refilled with the good old green stuff and not a problem since.

Go pick up a prestone flush kit from wal-mart or any local auto parts place, install it and flush the core. The fluid causes all sorts of gunk to build up in the core. My jimmy was an 00 and the core clogged in 03 with 60k on it. Installed the back flush, flushed it, refilled with the good old green stuff and not a problem since.

Skip the do it yourself kit and get it done at a shop. Antifreeze is a toxic subtance and it's illegal to dispose of in the sewers, streets or storm drain systems.

Here is the EPA web page adressing the subject: http://www.epa.gov/msw/antifree.htm

Skip the do it yourself kit and get it done at a shop. Antifreeze is a toxic subtance and it's illegal to dispose of in the sewers, streets or storm drain systems.

Here is the EPA web page adressing the subject: http://www.epa.gov/msw/antifree.htm

Where did I inform him to flush it into the sewers? The kit comes with a piece to allow you to direct the out flow to a container. Thanks for saving the environment but lets help the guy save 80 bucks. As well you can take the fluids to the auto parts store for proper disposal.

My 93 did this when I revved the engine it would work CHECK YOUR ANTIFREEZE LEVEL IMMEDIATELY Mine was a gallon low & when I put it in my heat worked but I had already blown the head gasket :banghead: My temp gauge read normal too so I didn't think about that. I would start there. then try the flush thing (at a shop or with a kit)

As for the Do-It-Yourself flush kits my 93 has one on it but it was installed when I bought it the 95 don't I was gonna put one on this summer but I don't know yet.

Where did I inform him to flush it into the sewers? The kit comes with a piece to allow you to direct the out flow to a container. Thanks for saving the environment but lets help the guy save 80 bucks. As well you can take the fluids to the auto parts store for proper disposal.

Some spillage is most certainly to occur with the DIY kits. The out flow container is marginal in containing a normal flush job and not adequate for the amount of flushing reguired to clear a major blockage and was only added to the kit to keep it on the market in spite of it's potential for enviromental damage. Be sure to get a kit with one, old stock is still sold without one. A professional flush and fill is under $30 labor, maybe $80 with a pressure test, which is a good idea.

So how much do you realy save by driving down to Walmart, searching for the right kit, taking it home and finding out you don't have the right knives to cut the hose, go back for the right tools, come home and cut the cooling line, loosing coolant and contaminating your self and the enviroment. Then you have to install two hose clamps over a cheap piece of plastic that will have to remain with the vehicle introducing three new possible failure points in the cooling system, all to save maybe $15?

Sorry if I seem to be on a rant but my wife had a Grand Mal seizure after accidental exposure to anti-freeze. She had about 20 mins of unconciouness afterwards, an ambulance ride, 4 hours in the emergency room and an immediate suspension of her driving privelages for six months. Since she had a CDL she was without work for six months also and had barely enough sick time to keep her senority. Nasty stuff, check it out here: http://www.iowapoison.com/index.asp?pageID=155

check the level in the radiator and barf tank. also, your system might need to be burped. you might have air caught in the heater core. park your blazer at a incline where the front end is higher that the rear. run engine to operating temp with the radiator cap off. fill if needed. fill the barf tank to level and start to rev your engine a little to force the air in the core out. hopefully this helps. I had to burp my system after replacing gaskets. also had to burb again after replacing heater core..

thanks for the help guys.. i thought it might be an air pocket also but after trying to "burp" it, the heat still isn't working well. i think i'll try the flush and do to my laziness, i'll help the environment too!!! i don't see myself doing this in my yard so i'll get it done at a shop. see, even lazy people are environmentally conscious!!