"Chainsaw" Heater Core Swap

[adrianpike]

So let's say you're heater core is failing. How do you know, you say?

• Leaking Coolant


• Smell of antifreeze with heater running


• No defrost or heat


• Some cases are bad enough that your windows will actually fog when you try to run the defrost

So you've got two or more of those symptoms, you've decided to do the heater core swap, and all you've heard about the job is how much a pain it is. Perhaps you've heard rumors, or in my case, even been given diagrams, that there is "a better way". Well, my friends, (droogs, if you will) there is a better way, and I'm here to show you how to do it, in true pictoral fashion.
There are a few names circulating around for this "hack", which it truly is.
The Chainsaw method, the Dremel method, and sometimes, it's just called "cutting a big hole in the side of the heater box".
Basically, to replace the heater core the classic way, it requires removing the entire heater assembly, which to do, you usually have to remove the dash. Removing the dash in and of itself isn't really all that horrible, it can be done. It's the removal of the center console and guages, plus the myriad of little electric glitches that will present themselves once you've put everything back together, that really gets you. Here is a photo of an assembly in it's natural environment, highlighted for your viewing pleasure.


So now, I shall speak of my better way. It's not for everybody, as it involves permanently modifying parts of your car that are in some ways better off unmodified, but it makes the job night and day easier.
Pros:
-Shaves hours off core replacement.
-Less headache with wiring
-Easy to replace in future
-Don't have to de-pressurize A/C system

Cons:
-Heater will be less efficient
-Ethical issues with a "quick fix"

Tools/equipment required:
-New Core
-Dremel or close-quarters hack saw
-Eye protection if you're using a powered cutting tool
-RTV Silicone
-Foam, with one adhesive side (weatherstripping works)
-Screwdrivers, socket wrenches, etc.
-Vacuum (not required, but desired)
-Sandpaper (optional, see below)

Here's a diagram of the cut you'll make, much thanks to kyle242GT:


And here's a photo outlining the same cut:

Note that the cut has to be curved around the top to create a slot for the core tubes to slide out, as shown in the next photo:


Now that I have shown and described the cut, I'll do a step-by-step process on how to swap in a new heater core, using the "chainsaw" method.

1. Remove the front passenger seat. This is optional, but it makes your life a lot easier.
2. Remove the fabric on the underside of the dash in the passenger footwell. It's held in by little black clips. All you have to do is turn them 90 degrees and they come out.
3. Remove the center console passenger-side trim, as well as the front trim. The side trim is held in by a screw at the top side of the front trim, and a clip, again which you turn 90 degrees, at the bottom of the front trim.
4. Remove the glovebox. Six screws, open the glovebox and they're on the lip.
5. Remove the passenger kickpanel. Again, this is optional, but you might as well, it's easy to pull out. Pull up the rocker trim, peel back the rubber weatherstripping around the door, and pull out the kickpanel.
6. Pull back the carpet as far as you like. This is optional, but a good idea, as it's very likely that some coolant will come in your direction.
7. Here's where it gets fun. Now you should be able to make out the heater unit, and now you get to remove the "oh %$@*" clips that hold the panel on the outside of the unit. Here's a photo showing where they like to hide.

They like to shoot off into the void when you pry them off with a screwdriver, so have something ready to retain them. I found that a magnet right next to the clip would grab it before it got a chance to zoom off into god-knows where.
Keep in mind that you may have to loosen the vertical support bracket for the dash on the passenger's side of the console to get at all the clips, and to remove the panel. I've outlined the bracket in the following photo:

Note that it has already been unbolted and moved out of the way.
8. Now that you've got the clips off, remove the panel that they were holding on. It may take some persuasion. Now you'll see the blower fan:

Pull the blower fan off by removing the clip. The clip slides up or down relative to the shaft, and the clip is narrower in the middle. The shaft is slotted for the clip to fit. Slide the clip until the shaft is in one of the larger holes and pull it out.
9. You might want to sand down the shaft to help the fan slide off it.
10. Slide the fan off the shaft. Be careful, I've got a cut on my finger that says it likes to bite.
11. Now remove the three screws holding in the backing plate for the fan.

12. Now go have a beer, because the goal is in sight! While you're at it, drain the cooling system.

13. Let's cut! Make the cuts mentioned earlier, and when you're done, this is what you should see:

Make sure and wear eye protection, and cover anything you don't want plastic dust on. A filter mask is a good idea here too.
14. Now that you see the core, remove the two coolant hoses that run to the top of it, being careful not to spill too much all over yourself (you did drain the coolant, right? ). Have a plug or rag ready to stopper the flow. The core slides out your hole easy as can be, but it may require a little bit of extra cutting for it to be butter-like. Don't cut too much, you've got to seal that hole back up in a few minutes.
15. Clean out the heater core area of any coolant, dirt, or plastic chips and dust that will have accumulated in there. This is where the vacuum comes in handy.
16. Slide the new core in the way the old one came out, and hook up the coolant lines to it.
17. Now, using an RTV silicone or equivalent sealing adhesive, glue and seal the plate that you cut out back into place, and let the glue dry.
18. Reassembly is the reverse of removal. Don't replace all of the trim until you test it out and make sure that all of your re-wiring is correct, especially the blower motor. This is a scary one to find doesn't work once you get everything back together.
19. No matter how well you vacuumed everything up, the first time you fire up the blower motor, a little bit of plastic chips and dust will come flying out. Don't worry about it, unless it lasts more than a few seconds.

[the poi]

I don't even have a 240 and I find this helpful. Great writeup, and I'm not even sure about the "less heater efficeincy", enough RTV ought to make it good as new. Sounds like the way to go

[kyle242gt]

Good job!!! ... though personally, I think the 240 core replacement should remain shrouded in mystery and disinformation to better separate the hardcore volvo maniacs from the wimps. Otherwise, the supply of solid low mileage cars, "for sale, runs great, needs heater core" might dry up.

[rwturbo]

Thats the way I have been doing it for about 5 years, done 15 so far and no complaints, it has become a 1.5 hr job. however I leave it up to the customer if they want it done the correct expensive way or shortcut cheeper way, as for I would never charge the customer the full given time, and so far have had only one want it the correct way.

[boostdemon]

nice, this will be a perfect article for our new "preventive maintenance" article section... to include things like poly bushing installs, seal replacment, headlights through a relay, other tricks we've learned etc..

[adrianpike]

Originally Posted by tryckjävel

nice, this will be a perfect article for our new "preventive maintenance" article section... to include things like poly bushing installs, seal replacment, headlights through a relay, other tricks we've learned etc..

Cool, I wasn't sure if there was any interest in maintenance articles, but I figured, what the hell. Let me know if anybody's got any ideas to fill in any holes or finds any typos, other than that it's pretty much complete.

[vurbo]

cool adrian, nice job!

[linuxman51]

thats a champion hack right there. there's a trick to 700 series heatercores as well, but I won't be sharing that one with anyone, it remains more of a rite of passage..

[stylngle2003]

adrian...thats so cool, gotta be one of the biggest timesavers around!

[boosted]

ahh, the 240's seem to be built AROUND the heater core

[dl242gt]

If you take off the dash you can get to the heater core from the top of the heater unit. That would be a lot less to cut. Then you just slide the core right out the top. Then you won't have to do as much disassembly of the console area. Plus with the new core installed the area to cover up won't affect the efficiency of the heater at all.

Nice job for an alternative method Adrian!

[adrianpike]

Originally Posted by dlot

If you take off the dash you can get to the heater core from the top of the heater unit. That would be a lot less to cut. Then you just slide the core right out the top. Then you won't have to do as much disassembly of the console area. Plus with the new core installed the area to cover up won't affect the efficiency of the heater at all.

Nice job for an alternative method Adrian!

Well, aside from the problem with removing the dash (in my case, removing the guages would be a biznatch) there would actually be a signifigantly harder cut to make going from the top. I'll try to explain with a diagram (viewed from the side)

Those braces keep the core from moving forward and back in the housing, and they would be a beast to cut through. You have to kind of nick the edges of them to cut the side panel, and that's pretty annoying. It would be nice to pull out the top... especially if the vent/speaker hole in the top was big enough..

[v240tic]

I don't see the problem, last time I changed the heater core "the propper way" it took me less than 3 hours. (but then I just might be a "hardcore" volvo mechanic).

[volvorod85]

I can get the dash out of a 700 series in an hour or less, center console and all. Now putting it back together, that takes up words of...oh 4-5 hours, depending how how you installed all of your electrical goodies. personally, im taking the dash off....again....cause the new heater core of 2 months....is leaking. *yelling and a sigh of whatever*
Mark

But a very good deminstration none that less! This wouldnt be the first car ive seen 'modified' for ease of heater core replacement.

[adrianpike]

Originally Posted by v240tic

I don't see the problem, last time I changed the heater core "the propper way" it took me less than 3 hours. (but then I just might be a "hardcore" volvo mechanic).

I guess you're a hardcore mechanic, but even the most hardcore of us get a little impatient when it starts pouring rain all over your shop, and the yellowjackets are literally flying into the spinning blade of your Dremel, because it's the only dry place for miles.
And volvorod:
Oh yeah on the putting back together. Taking everything apart is fine, but putting it back together (correctly) is a real biznatch. It's always cool when you put everything back together and have a screw or two left over. Or especially when your blower motor doesn't work.

So this thread has been around for a few days now, I guess it's almost time to zip it up and send it over to Dana... Anybody got any last additions to make?

[Tenacious Todd]

We call people like you at our shop (HACKS) .

[The Aspirator]

Originally Posted by adrianpike

Hahahaha, I LOVE the use of "VOLVO" font! I know it's not true old school volvo font, but it's what the new advertisements use. I've got it on my computer also.

Very sweet little write up you've done here! If I ever have to do a heater core swap I'll DEFINATELY be reading this one again. I like your use of pictures and really like how you outlined and highlighted everything important. Great job!

So how's it working? Nice and HOT? Not that it really gets cold in a pacific northwest winter, but it sure gets cold enough to want the heater bad enough!

John

[adrianpike]

Originally Posted by The Aspirator

Hahahaha, I LOVE the use of "VOLVO" font! I know it's not true old school volvo font, but it's what the new advertisements use. I've got it on my computer also.

Very sweet little write up you've done here! If I ever have to do a heater core swap I'll DEFINATELY be reading this one again. I like your use of pictures and really like how you outlined and highlighted everything important. Great job!

So how's it working? Nice and HOT? Not that it really gets cold in a pacific northwest winter, but it sure gets cold enough to want the heater bad enough!

Yeah, it works just fine. If I were doing it again, I would have got some wider weatherstripping to fit around the core for more of an airtight seal and therefore more heat, but my car never gets over about 60°, so it's not going to be scalding anyways. As it is it works great, let me know if you want to check it out sometime. Defrost is nice to have again.

Originally Posted by turbo16psi

We call people like you at our shop (HACKS) .

I call people who have a shop to work in (SPOILED) . But thanks for the compliment.

Originally Posted by dictionary.com

hacker

1. A person who enjoys exploring the details of
programmable systems and how to stretch their capabilities, as
opposed to most users, who prefer to learn only the minimum
necessary.

2. One who programs enthusiastically (even obsessively) or who
enjoys programming rather than just theorizing about
programming.

3. A person capable of appreciating hack value.

4. A person who is good at programming quickly.

5. An expert at a particular program, or one who frequently
does work using it or on it; as in "a Unix hacker".
(Definitions 1 through 5 are correlated, and people who fit
them congregate.)

6. An expert or enthusiast of any kind. One might be an
astronomy hacker, for example.

7. One who enjoys the intellectual challenge of creatively
overcoming or circumventing limitations.

Definition 6 and 7 are most appropriate in this sense, although number three works as well.

In my original writeup, I specifically said that this isn't for everybody, and those who have the time and patience to do it the correct way will be better off swapping cores the correct way. For those of us who care less about the work and more about the results, this method is ideal. Just in case you haven't noticed, this is in the "article composition" section, not off-topic. If you've got something useful or positive to say regarding heater core replacement and repair, say it. Otherwise, go post somewhere else, this isn't the thread for personal comments as to my ability or aptitude for automotive repair.

[Tenacious Todd]

I am A Volvo tech I was just admiring your work you did save a lot of money doing it yourself and that has to be comended for doing tit yourself..

[MARS]

Sorry to dig this up from 7 years ago, but all the links for the pics are dead, it's 8f out side and my heat is randomly blowing steam. Does any one have these pics?

[Koston740]

is this for 2 or 7 series?

[thelostartof]

Originally Posted by Koston740

is this for 2 or 7 series?

2 Series

[TestPoint]

Any chance of getting the 12 year old picture links back up?

[Eglacias]

I would hate to do this job without the photos. Can the original poster throw those back up there! Man, I PayPal you 15 bucks to do it :-)

If I never hear back, I’m going to re-post the entire original paragraph with my own pictures to update the site

[2turbotoys]

I don't think it saves that much work. I just did it the regular way using this: http://cleanflametrap.com/heater_core/ and a couple other things I googled since my car is older than the one in the link.