Leaking coolant inside

I just found a leak! I dunno how long its been going on for either! EEK! Its dripping right by my accelerator pedal. Its coming from the back of the heater. I'm assuming its a hose? Could it be my heater core? If so, how could it be my core?

I had my fan on the cold setting running high, and I got my accel pedal stuck so it revved almost to 6k! I shut the engine off, and then looked at it. Everything was okay. So I was going to work on my speakers and when I got down I noticed it was dripping. could the high rev have blown something?

Either that or its been doing it for a while. And I kind of notice it does'nt have alot of heat coming through anymore.

i would have to say it is your heater core leaking...if you pressure test the cooling system you could verify it or just disconnect the 2 hoses going to the heater core -bypass the heater core-install a bypass tube in between......good luck...

Oh, boy. Well, if it is my heater core, how does it go out? What causes it to leak? I don't understand...

Correct me if I'm wrong, but do I not have to pull the dash out to get to it?

It is just like ur radiator except on a smaller scale.Rads leak all the time and after awhile so do the cores.It is a beautch to get at.BJ

yeah i bypassed my core lot easier to bypass it then it was to remove the entire dash to replace it

Heater cores rot after some time... they either plug up or they leak.

When they plug up you don't have any heat in the vehicle. If they leak they usually do this where the coolant pipes attach to the heater core. This means coolant inside the cab or at the firewall inside the engine bay.

The bad news is that you need to remove the entire dash to access the heater core.

Search this site and you should find a techie on the entire process.

Good luck!!

post deleted

Here's hoping that's the case 'cause the "techie" below says otherwise...




Bagged89Mazda
Mazdabscene Supporter

Joined: 13 Apr 2005
Posts: 1087
Location: West Grove ,Pa

If its still cold and does not fix the issue then your heater core is clogged- before disassmebly order your self a new heater core and when it comes in then disassemble .


to change your heater core you have to unhook the hoses that go thru your fire wall in the middle of the wall be prepared for water/antifreeze there . And move them away . Now go in side - ready? ok- you're gona need 10 mm sockets to get the bolts out of the dash . thats right you have to remove the dash to get the heater core out of the truck no ifs ands or buts . I've taken 2 dashes out its not that hard to do -


break down :

***1 bolt on each end of dash (hidden by covers ) take them out -
on the top of the dash theres 3-4 bolts- you'll need to get a wobble extention as this is a difficult place to get with a regular socket-

***on each end of the dash theres 1 bolt on that stays in the dash you are removing the nut off it as this bolt slips into a bracket on the cab walls.

***Take gauage cluster out i believe if i remember right theres 1 bolt in there
under the dash again the lower vent that is screwed in - remove that theres a mounting plate for the colum - 2 bolts 14mm-15mm remove them that will let the colum lay down out the way .

*** open glove box remove insert theres 1-2 bolts in there -

*** remove heat /ac benzel and unbolt the controls for your vent and settings (simple little nuts one them ) you'll have to unscrew the heater control from the dash as you will have to push that thru inorder to get the dash away enough to gain access .



I'm sure i'm forgeting something but for warned if you do this your self its easy - and saves you money - sending the truck to a mechanic to do will cost you 300-400 simply cause of labor involved with takin your dash in and out . hehe . if i'd known how to take the dash apart 4-5 years ago i would have kept the mazda i had back then it had a bad heater core too- had wet floor - shop said 300-400 to do it -

the part it self will probably run you about 50$

DAMN I JUST wrote a techy . lol .

Well, I'm one step ahead of you guys! I pulled my dash out yesterday! I've done it before so it took me only a couple hours! It sure does bring up past nightmares! Lol! Wow I hated doing it.

Really, I did'nt need to pull my dash in the first place... Once I figurd it out I could have just got down upside down to fix it! It was indeed the hoses to the heater control valve! I replaced the hoses and gto new clamps!

It took another 4 hours to fix it though... I just wonder now if maybe I should replace the core since I have the dash out? I mean its not leaking or anything, but I dunno if it is clogged. I do get heat, but I dunno if I should be getting more heat than what it puts out? Lol...

So as I have my dash pulled, I'm going to pull the rest of my interior, AGAIN! I also have to take out the carpet, AGAIN now to clean it. My dad said the coolant won't evaporate and that I need to shampoo it?

Once everything is pulled, I'm going to dynamat it ALL! Then, I'm going to fiberglass ALL my panels and dash so I can paint it a gloss white! WOO! One thing is, I'll be without my dash for a WHILE! I rigged up my cluster to my column so I can drive a little more accurately. I just won't be able to see it in the night, so is there anyway I can rig up my guages to have light? I know the harness for the dimmer controls whether or not it lights up. Maybe I can connect a wire to the harness block for light?

Lol, dunno, maybe I'll just drive as fast as everyne else, lol!

I do that all the time on my moped 'cause the speedo isn't worth crap...