[MyNameIdeasWereTaken]

Did you find that the leaking o ring was causing a significant leak, or just dripping coolant onto the carpet? After experiencing a CEM on the fritz, I just discovered that my carpet has got some coolant on it. It isn't flooded and that makes me think o-ring vs. heater core.

Pull the fuse box down and you should be able to look at the connection point with a flash light. If the car is cool, you can touch the pipe and feel if any coolant has been dripping from the plastic clip connection area. It's an easier view if you pull the glove box completely out.

Mine was just dripping, maybe a few drops with every drive. I want to say about 2 weeks before discovering the actual problem, I thought the coolant level had dropped a few millimeters in the expansion tank, but I ignored this since I rarely park on a level surface.

I didn't mention this before, but my first attempt at replacing the O ring felt like it went flawlessly. Pipes fit together, clip fit on, topped up with coolant, and it practically poured out at the O ring area. Turns out I had a very slight pinch in the O ring when putting the pipes together. Luckily I planned ahead and had an extra O ring, but I don't even feel like the O ring is necessary with the hose piece I put on there.

 

[mercdude]

I really like your solution to the plastic clip. It's completely unreasonable to have a flimsy plastic clip retaining a metal o-ring slip-fitting together. A rubber hose with clamps makes perfect sense. I plan on doing the same, even if I have to replace the heater core. What size coolant hose did you use and did you find that coolant had been leaking onto your fuse box (CEM)?

 

[MyNameIdeasWereTaken]

I really like your solution to the plastic clip. It's completely unreasonable to have a flimsy plastic clip retaining a metal o-ring slip-fitting together. A rubber hose with clamps makes perfect sense. I plan on doing the same, even if I have to replace the heater core. What size coolant hose did you use and did you find that coolant had been leaking onto your fuse box (CEM)?

It was some spare radiator hose I had laying around. Measuring it, it appears to be either 13/16th or 7/8th ID. I bought about 10' of this hose from Autozone for ~$12 a few years ago. It was a very tight squeeze getting it on the heater core piping, but I could feel the bulged out area of the metal pipe and knew both halves were tight together before tightening down the hose clamps.

Of course, with this being one of my cars, this will probably be 10x easier for me than it will be for anyone else.

No coolant leaked into the fuse box, even when it was dripping out at a good rate. Almost all of it collected right on the rubber floor mat.

 

[mercdude]

Lucky no fluid hit the cem. Mines going nuts! And yeah, there's the mniwt ease factor to contend with but it still seems straight forward.


Sent from my iPhone using Tapatalk

 

[serum]

Can't tell from the pics, but couldn't it simple be fixed by some strong self vulcanizing silicone tape? I've got a few rolls of this stuff and it's amazingly strong. Just look on youtube. Perhaps it could save you a serious amount of time. i don't care if it's sealed by a failing hard to access o ring that sits on the inside or by a piece of removable tough silicone that's on the outside of the tube. So it might look like a ghetto fix, but it might be sealing better than the original o ring.

 

[mercdude]

My first thought is that the tape's adhesive wouldn't stand up to the high temp of the coolant - at least not long term. MNIWT is right, coolant hose is the sure fix for even a leaking O-ring.

 

[serum]

The point of self vulcanizing tape is that it doesn't use glue. I'm using that same tape for soldering tips on my finger. (Press hot copper tinned wire in a puddle of tin and let it cool down to settle, pressing it in to get the lowest possible ir on the soldering joint) it's for a low voltage and 100A and higher current. It withstands 450 degree c without deforming. Silicone is known for it's capacity of withstanding high temperatures. I think it would be ideal in this application, and it doesn't require the teardown of the pipe assembly. (With a hose, you need to take it apart and re assemble)

I'm using the aliexpress version, but it works as advertised. Feel free to tear it down, but i think this tape will work perfectly.. in order to protect the cem modules that keep failing on our machines, it might be a good mod as well..

https://m.youtube.com/watch?v=bdg_izrJK08

 

[AutoGeek]

Did you find that the leaking o ring was causing a significant leak, or just dripping coolant onto the carpet? After experiencing a CEM on the fritz, I just discovered that my carpet has got some coolant on it. It isn't flooded and that makes me think o-ring vs. heater core.

If your heater core is leaking, you should see coolant dripping out the condensation drain under the car. If the o-rings are leaking it is likely just the carpet. Pull back the carpet panel on the right side of the console and you should be able to see the connections or reach in an feel.

 

[AutoGeek]

After reading posts about CEMs getting screwed up by these leaking o-rings, I think I'm going to proactively bag my CEM to protect it. I had o-rings go bad twice in my old V50 on 160K miles. The 2nd time I must have put too much pressure on the heater core pipe and cracked the weld and had to replace it. Probably just tempting fate with this V50 at 100K.

 

[mercdude]

It could be that my CEM is freaking out because coolant is in the connectors vs. the CEM - not sure yet. I'll know more tonight and this weekend. I'm really really really hoping that once I dry out whatever is being affected that everything will be okay (seems delusional, even as I type it). If coolant is hitting the CEM, though, this is one of the worst designs ever imagined.

I only have a few drops of coolant on the RF mat but the carpet seems moist (hard to tell though, I have a black interior) + I'm getting some condensation on the far right side of the windshield now. I'm guessing it's just started to leak and is running down something (probably wiring). Just a nightmare.

 

[mercdude]

The point of self vulcanizing tape is that it doesn't use glue. I'm using that same tape for soldering tips on my finger. (Press hot copper tinned wire in a puddle of tin and let it cool down to settle, pressing it in to get the lowest possible ir on the soldering joint) it's for a low voltage and 100A and higher current. It withstands 450 degree c without deforming. Silicone is known for it's capacity of withstanding high temperatures. I think it would be ideal in this application, and it doesn't require the teardown of the pipe assembly. (With a hose, you need to take it apart and re assemble)

I'm using the aliexpress version, but it works as advertised. Feel free to tear it down, but i think this tape will work perfectly.. in order to protect the cem modules that keep failing on our machines, it might be a good mod as well..

https://m.youtube.com/watch?v=bdg_izrJK08

I've used similar stuff before to insulate the front O2 sensor's wiring from exhaust heat. It works pretty good and stayed for at least a year, but I'm not sure I'd trust it more than radiator hose with hose clamps though.

 

[mercdude]

Took my heater core apart. Found my cem dripping with coolant (and fried), about a gallon of coolant under my carpet, and the offending heater core leak. It turned out that the lower heater core line's snap connector came off and the exposed o ring got shredded. Must have been leaking for a while. <div style="width:480px;text-align:right;"><embed width="480" height="360" src="http://pic2.pbsrc.com/flash/rss_slideshow.swf" flashvars="rssFeed=http://feed568.photobucket.com/albums/ss129/mercdude/heater%20core/feed.rss" type="application/x-shockwave-flash" wmode="transparent" /><a href="javascript:void(0);" target="_blank"><img src="http://pic.photobucket.com/share/icons/embed/btn_geturs.gif" style="border:none;" /></a><a href="http://s568.photobucket.com/albums/ss129/mercdude/heater%20core" target="_blank"><img src="http://pic.photobucket.com/share/icons/embed/btn_viewall.gif" style="border:none;" alt="mercdude'sheater core album on Photobucket" /></a></div>

I ended up using a new snap connector, o-ring, and wrapping both line connections with silicone tape. Worked pretty well. But man, what a pain the engine compartment twist-lock radiator hose connectors are!

 

[serum]

Would you say it is possible to add silicone tape without taking it apart from the engine compartment? (Just in case, trying to prevent a leaking o ring)

 

[mercdude]

Definitely. I did that with the non leaking heater core line. You'll just have to take the front passenger side carpet out and seat and glove box then you have easy-ish access to the pipe connectors. The carpet and seat removal may not be necessary, use your discretion


Sent from my iPhone using Tapatalk

 

[mmustangsrus]

Thanks SS! For Another helpful thread

This is the project I’m tackling today


Sent from my iPhone using Tapatalk

 

[mmustangsrus]

Help!! I’ve got the HC lines fixed reinstalled the interior fuse panel. & hooked the battery back up
Stuck the key in the ignition. It went click no dash lights only interior lights & now I can’t get the key out of the ignition



Sent from my iPhone using Tapatalk

 

[240gator]

Help!! I’ve got the HC lines fixed reinstalled the interior fuse panel. & hooked the battery back up
Stuck the key in the ignition. It went click no dash lights only interior lights & now I can’t get the key out of the ignition



Sent from my iPhone using Tapatalk

Had this happen. I think it was the CEM, Go over all your harness connectors again. Remove them all and put them back on making sure they are locked in tight. Don't forget any either.

 

[tmtalpey]

Disconnect the battery first!

 

[mmustangsrus]

Had this happen. I think it was the CEM, Go over all your harness connectors again. Remove them all and put them back on making sure they are locked in tight. Don't forget any either.

Thanks!! Will do! Report back tomorrow.
Time to thaw out




Sent from my iPhone using Tapatalk

 

[Ben_B]

Great thread guys. Yesterday I noticed a maple-syrup smell when I turned my defroster on, and my windows are fogging up a bit after parking the car and having run the heat. Noticed some condensation on the windshield passenger side, checked under the carpet on the passenger side and there's definitely some small amounts of coolant starting to get under there (luckily not a huge amount yet.) Car is definitely consuming a small amount of coolant (between max and min over a couple weeks.) I reached up to check the pipes and didn't feel anything crusty or too wet (maybe a liiiiittle wet? nothing crusty and no big drips) but noticed the clamp on the upper hose is no longer attached and is dangling from the hose. Stuck my hand under heater core box and managed to find a little wetness/coolant, but not much.

What are the chances its the O-rings vs the core itself? Is the smell a dead-sign that it's the core? Would a leaky o-ring produce the same maple syrup smell when you turn on the defogger to high heat?

Called shop for an estimate on doing whole heater core ($$$ [a little over $1k] but not as bad as I thought especially with the high labor rate in my area and the price of the Volvo part) and I'm going to take it in next week. It's a good Volvo mechanic and they'll check everything out before doing unnecessary work. I'm going to tinker around with the tubes before then and least get the old clamp back on. Anything I should be looking for there? I went ahead and shoved a bunch of towels along the firewall and tunnel under the carpet to hopefully soak up anything new that leaks and will be keeping an eye on the coolant levels.

Any opinions on chance of it being the core vs the tubes?

Perhaps also worth mentioning that the rear of the car got fairly wet (took it apart and cleaned/dried it all out) from a clogged A/C condenser drain earlier this year. We just had some rain here so I've been fairly carefully checking the floor and sunroof drains (they seem to be draining fine) which is part of how I caught this, but the smell was my first real lightbulb moment.

I'm pretty annoyed by this...big ticket fixes for this kind of thing are frustrating, BUT I'm happy I caught it before everything got too soaked...this car has had me on my toes since I bought it and I'm catching things early.