Replaced heater core but still leaks!!

flamo · Postby **flamo** » Fri Jun 18, 2010 6:33 pm

I done the no removal of dash heater core removal today. I noticed the core I took out looked pretty good and didn't notice any cracks etc. I replaced It anyway and put it all back together. I hooked up hoses again, started car and let it run for a while and it still leaks. It is a small leak in passanger side footwell. I am guessing I am goin to have to remove whole dash now and replace pipes. Before I do anyone have any other possible reasons why it would still be leaking? And I have searched but could not find a guide
on removing dash, anyone know one?

Mr Morlock · Postby **Mr Morlock** » Fri Jun 18, 2010 6:52 pm

if you replaced the core with a new one then it will not be leaking. The leak has to be identified but simple explanation is hose connection??

ak_perth · Postby **ak_perth** » Fri Jun 18, 2010 8:26 pm

Hi flamo,

I dont know what year your car is but I found a pdf which tells you how to remove the dash for 89-93 MX5 if that's any help?

www.miata.net/garage/DashRmv_89_93.pdf

Cheers

AK

wun911 · Postby **wun911** » Sun Jun 20, 2010 3:35 am

If your kinda lazy, you can bypass it, and just not have a heater core with flud running in it...

Benny · Postby **Benny** » Mon Jun 21, 2010 5:38 pm

If it's leaking in the passenger footwell, it could be the air conditioning as there is a tube there that gets rid of the water that is pulled out of the air.

Lift the carpet on the passenger's footwell, and you should see a plastic tube with a T piece in it.
This tube can come undone, and when it does, it drips water into the footwell.

greenMachine · Postby **greenMachine** » Mon Jun 21, 2010 5:58 pm

It is possible, but not likely, that the new core that you installed is faulty. :frown:

Not having used the method that you used, I do not know if this might have happened, but if you had to apply any force to position the core properly, you may have opened up a joint or something similar.

The air-conditioning drain is your best bet, for a cheap fix! How would you feel if that was the problem all along, and you didn't need to replace the heater core? I think that I can guess ...

:mrgreen:

flamo · Postby **flamo** » Tue Jun 22, 2010 9:17 pm

Thanks for the help

I ended up pulling the whole dash out and found that one of the copper pipes that run from the firewall to the heater core had a crack in it. Replaced it, and put dash back together (didn't test it until I put it all back) and than found that I had damaged one of the rubber hoses that connect the pipes to the core so it then started to leak from there. So I than had to pull out the core again and replace the hoses, lukily I did not have to pull the dash to do this.
So to fix this small leak and get my heater working again I spent 2hrs replacing core, 8 hours pulling dash and replacing pipe, another 2Hr to replace rubber hose.. After all that i guess it's still worth it, especially at 5am
on the way to work lol
Thanks for the guide on pulling the dash, it came in very handy!!

Postby **Okibi** » Tue Jun 22, 2010 9:27 pm

I've replaced a heater core - I feel your pain.

Postby **NitroDann** » Fri Jun 25, 2010 12:56 pm

I recently had a leaky heater core and i replaced it via the drivers footwell but ended up snapping one of the heater core controls and had to remove the whole dash to plastiweld one tiny broken bit. While i was there i found heaps od dodgy wiring done by previous owners, almost as bad as the stuff i found on the loom at the computer when i wired in my Link.

Dann

justinowell · Postby **justinowell** » Fri Jun 03, 2011 3:23 pm

flamo wrote:I done the no removal of dash heater core removal today. I noticed the core I took out looked pretty good and didn't notice any cracks etc. I replaced It anyway and put it all back together. I hooked up hoses again, started car and let it run for a while and it still leaks. It is a small leak in passanger side footwell. I am guessing I am goin to have to remove whole dash now and replace pipes. Before I do anyone have any other possible reasons why it would still be leaking? And I have searched but could not find a guide
on removing dash, anyone know one?

It could or could not be the heater core, but I know several similar scenarios and all of them pointed to a malfunctioning heater core.

jerrah · Postby **jerrah** » Fri Jun 03, 2011 3:36 pm

Would love to know how to replace the heater core without pulling the dash? I did mine about two years ago and fingers crossed it lasts another 20 years.

NitroDann my ECU wiring thankfully is in good shape, but there's a real mess on the drivers side. I took out about a mile of wire that wasn't required. If I was doing it again I would have probably found a unmolested replacement loom.

devski · Postby **devski** » Sat Jun 04, 2011 12:54 am

I got mine replaced by a mechanic under statutory warranty.

For those interested to know, a heater core replacement in an mx5 will set you back around 2 weeks of no car and $980
The two weeks was most likely because I live in tassie and we have very little parts down here!

Postby **NitroDann** » Sat Jun 04, 2011 3:30 pm

jerrah wrote:Would love to know how to replace the heater core without pulling the dash? I did mine about two years ago and fingers crossed it lasts another 20 years.

NitroDann my ECU wiring thankfully is in good shape, but there's a real mess on the drivers side. I took out about a mile of wire that wasn't required. If I was doing it again I would have probably found a unmolested replacement loom.

You look under the middle of the dash looking from the pedals towards the passenger side of the car, the heater core has a plastic cover over it. take it off, undo the clamps. Slide the heater core out.

Dann