Whats messed up...Heater Core or the Pipe going to it?
 

Few weeks ago I sprung a leak in the heater hose (one that starts under the oil filter, bends a few million times and connects to the firewall)

Did the reinstall, used some RTV to seal the nipple because it was all crumply and not nice and circular and now I'm leaking coolant from somewhere...

When I redline the car (doesn't even have to be in gear) splashes of coolant come onto the driver side mat and pedals, theres no coolant leaking from where the hose attaches to the messed up nipple on the firewall..

I searched and found out that it might be messed up on the inside or it might be a faulty heater core (which is what my mechanic immediately said when I showed him the coolant coming onto the drivers side)

Basically my question is what should I do to check if its really the heater core or just a pipe connecting to it...heater core will run me 90 bucks and a weekend of sitting in the driveway with my entire dash in pieces, what can I do to fix up the pipe if thats what it is?

It's definitely not the new hose I installed, and I didn't think it would be the heater core because I don't smell coolant when the defrost or the heat is on which is how I always thought you test the heater core..

If its not the heater core how do I go about fixing this thing?

Final note, the nipple stickin outta the firewall was thoroughly coated with RTV because of my paranoia about it leaking and lo and behold it leaks in new and interesting ways

Thanks for reading this giant post, I appreciate your help guys

Probably just the nipple. If you still have the ghetto mazda clamp on there, get a regular band style clamp and tighten the crap out of it. Should fix your problem.

Did you let the RTV cure completely before you put coolant back in the system? And did you clean the heater core pipe off thoroughly with a good solvent to remove any coolant oil residue? (Before the RTV application)

I cleaned the nipple off real good with the stuff plumbers use...flux I think its called I don't remember, something my friend had

I bought two new clamps when I ordered the hose and they are tight (I'll check if they still are?)

Also I let the RTV cure for like 3 hours, friends and I went out to lunch when I was done

could it be anything else?

PS: thanks for the replies..I think Wayne is my new best friend whether you like it or not :)
always helpin out..thanks man

How did you remove the old hose? Just pulling it? Cut it? Muscle it around at all? You may have worked loose the soldered connection from the inlet to the core, and if that's the case, there probably wouldn't be a leak at the firewall, just inside the car. Sounds like you'll have to remove the core, if you're sure the leak is not at the hose connection. If you've broken the solder at the inlet to the core, a radiator shop will be able to resolder it for you, assuming the rest of the core is good.

I don't know how "circular" you managed to get the pipe, but if you had a pretty big ding in it, and tightened the clamp before the RTV set up, the clamp would have deformed the hose, depending on exactly where the "ding" is...Hmmm, plumber's flux? The stuff you use for PVC & CPCV pipe? Or the stuff you use to acid etch copper tubing before brazing? Either one...Hmmm...

Dude, the easiest thing to do right now, unless you really want to abuse yourself & get to that heater core, is to try to remove the hose again, without further damage to the pipe...If it was RTV'd correctly, it will be a royal pain to get back off. I'm thinking the pipe wasn't prepped correctly (the RTV won't adhere properly if any "foreign substance" was on the pipe). Get some acetone, MEK, or toulene, (the "manly man" solvents) and clean her back up again. Also, don't shove the hose all the way on-leave a little space at the end, so that if you do leak, it will tend to remain in the engine compartment instead of the cabin...

Nopistons might have nailed it, too :)

remove the heater core and lines and everything under the dash......the 7 needs to lose a little weight anyways.

the flux I used was the one you use to clean copper piping up before you solder things..

I didn't put the clamp on until the RTV was cured, I got the hose back on pretty well...there won't be any way to get the hose off w/o cutting it which means I gotta order another hose..

I'm afraid that nopistons will be right, I talked to my buddy who helped me get the old one out and he shamefully admitted that he really went to town on the sucker when I was up here when the hose first blew up...of course he can admit it now that he's 3000 miles away right..so it looks like that solder joint thinger is messed up and needs to get redone which means the whole dash is coming out...:(

Where would I be looking once I get down to the bare firewall..from the engine bay the rubber hose attaches to a copper nipple that does (insert answer here) and somehow magically hooks up to the heatercore?

thanks again for all your help

RX7racer, I'd do that in a second if I didn't need the defrost when old man winter comes around

also...this is somewhat unrelated but I bet Wayne knows the answer...

when I drive it lots of hot air comes out through the shifter area..I've searched on here and read that its the shifter bushings that I should get from Mazdatrix, so I'm thinking about putting an order through for that..maybe toss in a short throw shifter too :)
The problem is theres also heat coming out of the vents and stuff even when the heat is off..what could be causing that, I figure if I'm taking the dash out tomorrow I might as well take care of everything I can right...?

thanks guys

Well, your air mix motor door might not be doing its thing, for one, which means your air mix motor or logicon might not be working. While driving, can you hear the door switching positions when the temp range knob is moved?

The shifter heat is totally unrelated, there are strips of insulation that are supposed to be in there, plus your rubber boots at the bottom of the shifter should be keeping some of the heat out. Even if everything's perfect, though, you're still going to feel some heat, if you're paying attention to it...

Yeah I hear something moving around when I move the temperature slider...

also about the shifter, worn out/completely gone bushings wouldn't cause more heat to come in? (I need new bushings anyway because when the car is in gear I can move the shifter side to side pretty damn far and I'm pretty sure that means I need new bushings...

Finally note on the original issue at hand the leaky coolant, I couldn't finish ripping the interior apart today but tomorrow morning I will have it in pieces and hopefully find the root of the problem...

thanks for your help Wayne I don't think I can ever thank you enough, but I'll sure as hell try

updates:

its done, car's running, for those wondering, it was the inside section of the pipe, not the heater core, but it was a bitch to get in there...

its all back together and done, although many pieces of plastic broke during the process, meh you can't win them all

thanks for all the help I got :)