DIY: Heater core replacement

[SoundAdvice]

Yes, I reckon next time it could be done in a day. Could it be that the car was originally designed as a LH drive, then modified for RH?
We are keeping the Mirages here. Zero road tax, up to 66 mpg (UK), and low insurance, second-hand value increasing!

[foama]

Sadly this is a right-hand drive car. The pipes are different, plus extraction of the heater is obstructed by the blower, input filter and recirculation actuator - all of which would need to be removed. I'll take a look though, as my other car is the same model and year and will probably go the same way. Deep joy.

I can imagine what it looks like, but as Fummins said, pictures for the forum would be great! In Japan and some other east Asian countries, RHD cars are the norm, so I can imagine this car was originally designed as RHD with differences designed later for LHD. That lets you expect the RHD design was made thoroughly.

A note of caution: mine was clogged with lime scale. I am the first and only owner of the car, and only once added less than half a pint of tap water. Thats the only way lime scale could have been introduced. A blasted half pint of hard tap water clogged the core!
My advice: Never use tap water, but use demineralized or distilled water instead! The cost of demineralized water is so miminal, maybe less than one Pound, so don't scimp on that.


We have a how-to for replacing the core:

https://mirageforum.com/forum/showth...-core-with-pix

PS @ SoundAdvice: Just saw your most recent post and agree with everything.

[SoundAdvice]

We have hard water here too, however as I bought 5 L of G30 and could only get 2 L of it into the cooling system then I didn't go for dilution. I flushed and refilled my other Mirage with the remainder while I was in the mood.



Picture is of a RH drive 2013 Mirage 3 prior to removing the horizontal bar and lowering the steering. On the left you can see the two pipes going to the heater which is only visible after removing the actuator above the blower. The dash airbag is a single connector which is easily removed. I disconnected the battery after the car had shutdown (measured with a DC current clamp) and then waited a half hour to ensure all the ECUs had ceased to function before disconnecting the air bag. No problems on powering up.

The other thing to mention on cars of this age is while the battery is disconnected its worth loosening all the high current terminals and retightening to break any oxidation and gain good electrical conductivity.

[foama]

I sure hope you didn't have to remove all that for changing the core..?

[SoundAdvice]

The horizontal bar had to be removed from its mountings but then lowered slightly in-situ with the steering mechanism to allow the heater box to pull away from the bulkhead in order to extract the heater pipes.
And breath.
The major removals were the dash and all components attached to it, plus the air intake box and blower.

[foama]

Wow, thats a lot more than I did:
https://mirageforum.com/forum/showth...-core-with-pix

[SoundAdvice]

Wow, thats a lot more than I did:
https://mirageforum.com/forum/showth...-core-with-pix

It is...I guess that's because mine is RH drive and yours was LH drive.

[Morphector]

Just stumble on that link on an outlander phev facebook group...

There's a picture with a blue goop in a strainer that really ressemble of the one we saw in multiple mirage heater core...

https://carhoodsecrects.com/mitsubis...Qz4pBvUnjkMDTc

[Top_Fuel]

...if the dealer replaces my core with another OEM core and...OEM coolant...will I be looking at the same thing two years down the road?

No...you should be fine. A new heater core will restore your heat to 100% for many years to come.


My 2015 has the same problem your car does. I made the decision not to have the heater core replaced under warranty for a few reasons:

1. A lack of heat on 1 side isn't a huge deal if you have mild winters.

My car has plenty of heat 99.9% of the time. There might be 2 days out of the year where it's 5F outside and my defroster struggles to clear the windshield on the passenger side. Where I live (southern Ohio), I can get by most winters without even noticing. If I lived in Wisconsin, Minnesota, Canada, etc...then I may have a different attitude about it.


2. I didn't want a dealership tech tearing my dash apart.

This is a pretty involved job and a lot of stuff has to be taken apart to access the heater core. You have to hope that the guy doing the work has done a bunch of these already and knows how to do it the right way. The downside is something might go wrong...and you might end up with some mystery squeaks in your dash that weren't there before they did the repair...or maybe they screw something else up.


3. I think an unconventional flush method might cure my problem.

If my problem suddenly got worse, I would try soaking the core in some "alternate" liquids...or I would have an independent shop do it for me. We have done some experimenting with different liquids that looked like they might be able to help clear out the core without removing or replacing it.

[Eggman]

3. I think an unconventional flush method might cure my problem.

If my problem suddenly got worse, I would try soaking the core in some "alternate" liquids...or I would have an independent shop do it for me. We have done some experimenting with different liquids that looked like they might be able to help clear out the core without removing or replacing it.

+1 on the flush in place.

This is just a suggestion. Wait for warmer weather and use the time to look for a mechanic you know & trust. Ask that they disconnect and bypass the heater core and treat just the core with a cleaner. I found ammonia detergent works to dissolve the goo. Soak & flush it five times then thoroughly rinse out any remaining ammonia residue. Connect the heater core as it was and fill with your favorite new coolant.