DIY: Heater core replacement

[Cobrajet]

I repeated the same test as above...this time using mineral spirits...

Attachment 20349

The results were slightly better than paint thinner. After 48 hours of sitting in mineral spirits, the flux was mostly dissolved and it completely fell apart and disappeared with some minor shaking of the jar.

If this goo is petroleum-based (like flux) then mineral spirits should break it up and cause it to fall off of the surfaces of the heater core where it has deposited. At that point, you would still need to flush the core to remove the dissolved goo.

I will probably try this on my car once the weather warms up. Using a method similar to what Doax did, I would fill the heater core with mineral spirits and let it sit for at least 48 hours. Then I would fill a 5-gallon bucket with hot, soapy water and pump it through the core (in both directions) to clean out the residual dissolved goo.

It sounds good in theory and it won't take a ton of time, effort or money. If it works, it could potentially save replacing a heater core.

This makes me want to unhook both heater hoses and connect them together, cap both heater core inlets after filling the core with spirits, and let the mineral spirits do their job all summer long. The natural jostling of the car while it is being driven should have the same basic effect you got when 'shaking the jar'. When fall comes, blast the core out with water pressure and see if there is an improvement. If you got those kinds of results in 48 hours then the results we see over 90 days might be impressive.

A few bucks worth of mineral spirits and some hoses sounds like a much better idea than tearing the dash out, and switching to a different coolant may keep the clogging happening again.

[Top_Fuel]

...unhook both heater hoses and connect them together, cap both heater core inlets after filling the core with spirits, and let the mineral spirits do their job all summer long.

I never considered filling the core and then continuing to drive the car around. Maybe build/install a heater core bypass like the one foama built.

From what I've read, mineral spirits won't harm aluminum or copper. The inlet/outlet tubes appear to be above the level of the core, so keeping it submerged shouldn't be an issue.

[Cobrajet]

I never considered filling the core and then continuing to drive the car around. Maybe build/install a heater core bypass like the one foama built.

From what I've read, mineral spirits won't harm aluminum or copper. The inlet/outlet tubes appear to be above the level of the core, so keeping it submerged shouldn't be an issue.

Exactly like what Foama did. Then fill the core with spirits, cap the inlet/outlet tubes, and put about 8,000 city miles on the car from June to August. I figure the solvent combined with the natural sloshing and jostling associated with driving the car, plus the summer heat, might do the job of flushing the core?

Not like I need a heater in the summer, right? Worth a try, maybe?

[Cobrajet]

Impossible to remove or reinstall? I already pulled one from a wreck this way and didn't ruin it. Reassembly would be a pita. If that's impossible, how about cut the tubes with a ratcheting pipe cutter and reassemble with a couple pieces of hose and some clamps? I did this in my 02 Dodge instead of draining the ac and removing the entire heater box to get the heater core out.

As I mentioned, I have thought of doing this myself.

Drain coolant or clamp the heater inlet and outlet hoses under the hood with hose clamp pliers. Make enough room under the dash to cut the heater core tubes at the locations indicated by the red arrows with a pipe cutter, Dremel, etc. This would include completely removing the 90 degree turn in one section of the tube as indicated. Slide the old core out, again moving components as needed. Cut the tubes on the new core in the same places. Slide the new core back in. Reconnect the old inlet/outlet tubes with the tubes on the new core using heater hose and clamps. A 90 degree elbow hose can be purchased by itself, as shown below.

As near as I can tell, the only thing that might get in the way are the brake/clutch pedals and/or steering joint, but I think the core might actually slide out behind them. There is one control module directly in the way, but it can easily be removed. I would rather loosen the pedal brackets and move a module than rip the whole fcukin' dash out.

I looked up under the dash yesterday and this looks feasible. Thoughts?

[pawpaw]

As I mentioned, I have thought of doing this myself.

Thoughts?

I thought of trying something like this but was too worried about coolant drips stinking up the passenger compartment. The tubes are not necessarily perfectly round in these areas. If it works you will save a ton of work. If it fails you are in a pickle.

Just yesterday I found my own replacement job was dripping in the engine compartment at one (or both) of the hose connections. Hopefully it is not a tubing crack and just too much messing with the hoses. I probably had them on and off four times at least. I bought new hoses and found these interesting new (to-me) clamps that I plan to try...



These sound like they will seal out of round/irregular connections better than the standard spring/screw clamps. Could be a possible part of a cutting solution if you are brave enough to go there!

edited to add... when I replace the hoses I plan on lubricating the attachment with a tiny bit of silicone grease to help make sure the new hoses/aluminum tubes are not damaged during install. Another trick I came across but never tried myself.

[Top_Fuel]

...I found my own replacement job was dripping in the engine compartment at one (or both) of the hose connections.

Those clamps sound interesting! Let us know if they work.

If you got rid of the OEM hose clamps and installed worm-gear hose clamps on the heater core connections, that might be part of the problem.

Check out this video explaining why (start watching at 1:40).

[pawpaw]

Those clamps sound interesting! Let us know if they work.

If you got rid of the OEM hose clamps and installed worm-gear hose clamps on the heater core connections, that might be part of the problem.

Check out this video explaining why (start watching at 1:40).

I kept the original spring clamps so I am more worried the aluminum tubing is cracked or out of round or the hoses were damaged by my previous efforts. The crack is my biggest fear because there is no way I want to do another Mirage heater core in this lifetime!

1/9/2022 - I never tried the Gates shrink clamps so the new hoses and clamps are still sitting in a box in my garage, I re-positioned the original spring clamps and hoses thinking "this will never work" and, well, it worked!, at least well enough that I have not seen noticeable leaking since

[skudder]

I just want to say thank you to everyone here. I have 2015 and I had smell of antifreeze in the cabin, scheduled service, but needed to make run. On way home I got hot coolant sprayed on my feet. Heater core is the issue. I had the thermostat warranty replaced at a dealer in 2018 since it didn't have any heat, now this one. I was quoted $450 for the part and the tip to get it at rock auto saved me a good chunk of change. The walkthrough here made me confidant that there was no way I had the time or know how to do it myself And will get a good after market coolant so this doesn't happen again. Love the little car and the gas mileage it gets me. Such good info here and you all are so helpful. I'll save the old heater core if anyone wants it to keep trying things with the blue goo. Would have been nice to know before hand to swap out the manufacturer coolant right away. Will probably just do that with every car now so I know I'm preventing build up. Thanks so much!

[Johnny Mullet]

Glad we were able to help. If anyone is interested, I work on these and other cars in my garage at home and already done 2 heater cores and one more coming in a month. I do the job correctly and damage free for $400 labor.

[domisvo]

Hi guys,its time to replace the heater core in my 2014 mirage(1.0 (52 KW / 71 PS) (05.2012 - .) and i have 2 questions:what is the size of heater core? 83x218x16 & 84x219x16,found 2 types.and the other what trademark is best of??Nissens?Thermotec?
https://www.autodoc.gr/exartimata-af...56018-1-0-a05a