Hi guys, 23 y/o vehicles have one problem after another. I lifted up my driver's side floor mat 3 days ago to find a puddle of antifreeze on the floor. The heater still works, but there must be a leak in the heater core. It can't be too bad of a leak, but i do notice a drop in coolant after a couple of days. The weird thing is that I see the puddle on the floor, but can't trace a wet spot on the carpet up to anywhere, its just like puddle but no trail. The rear lines to my rear heater in my 1985 4Runner SR5 were leaking so I bypassed them on the firewall. I don't think that has anything to do with the leak. I was wondering how hard it is to replace the heater core and the best way to do it. I tried some Bar's leak liquid aluminum slimy crap that says it will stop heater core leaks, but I don't think its working too well. Thinking about dumping another bottle in, but that may be a bad descision. Any advice is appreciated as always. thanks. <img src="/forums/images/graemlins/confused.gif" alt="" />

Haven't had to do it to a yota but I've yanked a dash before in an Isuzu. Not fun the first time but gets easier the more you do it. Hope once is all you have to do it!! Any Chiltons/Haynes manual will tell you how to do it. Usually entails pulling your steering wheel and removing some heater tubing. The harder side will be the drivers side. Probably have to disconnect your speedo and wiring harnesses.Now would be a good time to replace any burnt out bulbs in your dash cluster. Make sure you don't lose any of your speed clips, not the end of the world but a pain in the a$$!! I ended up with a few extra screws the first attempt and tore it back apart to find them.

#1 Do not put any more additive cr*p in there. In fact, before you go removing the core, FLUSH THE WHOLE WORKS. You might save your radiator in the process.

Heater core replacement isn't fun nor easy, no matter how you do it. If you're a big fella, you might consider pulling the seat to have some more room to move around.

Now, you said DRIVER'S SIDE. Are you sure it isn't clutch fluid? Your heater core's on the pax side. <img src="/forums/images/graemlins/confused.gif" alt="" />

Check your brake and clutch fluid levels.

Can the additive crap do some damage? What do you mean by save my radiator? The liquid on the floor seemed watery unlike clutch and brake fluid. I will check again, but it really seems like coolant. I also cannot find a trail, just the puddle. The rear heater line leak was spraying upwards from underneath when it happened, but the chances of it somehow going through the floor seems small. If the heater core is on the passenger side I am really confused. I am hoping someone with similar experience will help.I need a vacation <img src="/forums/images/graemlins/zombie.gif" alt="" />

additive plugs holes.... additive doesn't know the difference between a hole / port / tube ect... it will plug / block those openings too... other parts to cooling system = radiator.. plugged rad will overheat... not to say that a tube will block up the rad and your hosed, but it could on an older rad that already has rust floating around.... Kinda the double edged sword can help and can hurt... i've seen a guy throw 2+ tubes of that through his stuff and rad is still working, but to what avail??


Last heater core I did was on my 83 Mustang <img src="/forums/images/graemlins/ignore.gif" alt="" /> I had in high school - yes a PITA!!! and on the pass side...
maybe yours is leaking and running across something then dripping on the drivers side??

I'm kind of beginning to wonder if what you're seeing might be rain water. There are a couple of drain holes under your windshield grille that can get clogged and not allow the water to drain, and it ends up in the cab. Few folks here have had that issue.

If you carefully remove the closeout screen in your glovebox, you'll see the heater core; it's to the left of your blower motor, and to the right of your A/C, if installed.

Thanks alot guys, lots of good suggestions, you might have something there with the rain water b/c I have those heavy rubber mats, and who know how long the puddle was under there. Thing is I vacumed it out 2 days ago, and the water is what looks like to be slowly coming back. Its skanky, but do I dare dab my finger and taste it to see if it is sweet tasting. I'll try anything that doesn't involve the removal of the heater core right now. <img src="/forums/images/graemlins/rolleyes.gif" alt="" />

Is it the same color as your coolant? If not, it is unlikely to be coolant. If it is, time to learn what's under the dash....

Update: I peeled up my carpet on the driver's side and there is warm dampness on top of the tranny hump behind the radio. The leak appears to be before the heater core, perhaps right when the lines come into the cab, its not big but plenty annoying. Is there an easy way to get to the hoses/connections instead of the heater core, perhaps by pulling them out through the outside or something? Tomorrow I will look at it closer (time for work now) and see if I can find something else out. thanks.