I can't believe it - I bypassed my Heater Core!

Post by **taxidad** » 19 Feb 2011, 01:40

My '99 V70 XC (that I never want to sell), has been giving me a little grief lately. Picking up my kids from school, I turned the corner & heard what sounded like a balloon bursting in my dash! Steam coming out & windscreen fogging up - Oh no! After picking up the kids I opened the rear passenger door (right hand drive) - green pool of water on the carpet. I'd parked on a slope and this is where the coolant ended up. So I call my mechanic. "Oh that's not good" he says. "That's your heater core. We'll need to pull out your whole dash to get it out & replace it. More than a day's work - expensive. We could bypass it & do it down the track if you need the car now." So I check Matthew's Volvo site & discover that it's a bit awkward but the whole dash doesn't need to come out - I also discover that it's a reasonably easy DIY & a simple bypass will get me by until I can get a heater core.

So I have a look at where the cooling system runs into the Fire Wall in the engine bay - no idea how to take them off! Where are the hose clamps? Discover as I sift the postings also that they are "quick connect" fittings, and spend a lot of time looking for someone who has described how to "quickly disconnet" them. It's probably here & but I couldn't find it & read some talk about breaking the plastic couplings while trying to get them out with a screw-driver - don't want to do that. I had a long look at the connections again, wriggle the copper (or brass) tubing around a bit, and discover what looks like a way to squeeze a light coloured plastic connector ring. Squeeze and gently pull - whalla; out she comes. Same with the other tube. All I needed now is some 5/8 radiator tube to clamp around the metal fittings, which I found at an auto parts place. It needs to be in somewhat of a U-shape already to avoid a kink, and undue stress on the connections. It seems to be fine so far - Here's what I did - I'm new at this, so any other suggestions are welcome. I was wondering if I should secure the connected hoses in some way - at present they seem fine leaning against the fire wall until I can replace the heater core.

: Hose connections at firewall before removal.

: Squeeze lugs on connector ring.

: Work the pipe out while sqeezing lugs - came out with no difficulty.

: Both hoses detached.

: Clamp a curved 5/8 radiator hose to each bard & you're done.

Post by **mikealder** » 19 Feb 2011, 02:47

Excellent write up and I hope the heater core replacement goes to plan - Mike

Post by **precopster** » 19 Feb 2011, 03:19

Welcome to the site. Well done!!

Now you can step up to this little job:

https://www.matthewsvolvosite.com/forums ... =1&t=36218

Post by **taxidad** » 24 May 2011, 00:31

Update on my heater core bypass. Turns out I had a blown head gasket which the mechanic says is why I blew the heater core - gases leaking from the engine into the cooling system building up too much pressure. Even after I did the bypass, I was still losing coolant. I replaced the cap three times. Before the heater core blew I had split a coolant recovery bottle. The strange thing is that I have never overheated the engine, even when I was running around with the blown head gasket. The mechanic said that this fact is testament to how good these engines are - cold comfort when I still have to foot the bill to have a big job done.

elchopperfreak · Post by **elchopperfreak** » 24 May 2011, 00:41

Cool
Doing the same, but permanent, since I have no use whatsoever for the heater..

lfilson · Post by **lfilson** » 19 Apr 2012, 19:33

How much did the head gasket wind up costing and how did you figure out that it was blown?

zandaink · Post by **zandaink** » 11 Dec 2013, 17:55

Thanks for posting this!! I know it's an old post but it helped me fix my problem in the parking lot of an auto parts shop... I have long nails so it was a little tricky but otherwise super simple

I noticed foggy windows & crappy performance of the heater on my 99 v70 wagon I just bought. So I knew the heater core was going out.. I had no idea it would flood the back floorboards when it did though!! OMG it was crazy & took a moment for me to figure out why the ehhf antifreeze is IN the car. But now I know.

I'll be buying a new heater core soon and hope to put it in myself, but as of now this bypass fix is doing a great job.

Thanks yo!

Post by **rspi** » 11 Dec 2013, 22:05

dwhite66 · Post by **dwhite66** » 14 Dec 2013, 17:32

Thanks for this post. I did a similar bypass process on my 98 V70 GLT when the heater core failed, but inside the car under the dash with much less hassles, after removing the heater core which took me probably 10 minutes. With an approximately 16" section of 5/8" heater hose obtained from a local auto parts shop and a couple of clamps, I created an effective loop at the connections and all worked perfectly while waiting for the new core that I had ordered. Fortunately it was during the summer here in Arizona and it did not affect the a/c operation at all. I did not think about it until afterwards that I should have taken pictures or video to post here. It is a really great bit of engineering that the heater cores in these vehicles are so easily accessible. I removed and replaced my heater core at a slow pace in probably less than an hour total, including refilling the system with the OE coolant. It took me longer to clean the carpets from the coolant damage.

It is from the video posts and this forum that showed me how easy the task is. Need I say how grateful I am for that. I have owned and serviced my Volvos since 1982 when I bought my first 145. Although there are other vehicles that I like, a Volvo is my first choice and preference over any others.

Post by **j-dawg** » 26 Oct 2014, 00:13

lost my heater core on the highway today. it's a surreal experience, that moment between feeling steam on your hand and realizing what's happened. i'm going to go back tomorrow morning and bypass the core, but i'm just trying to make sure that i can cover all possibilities - since i'm getting a ride from a friend, i'll have to bring everything i need in one shot.

any advice as to what to bring with? i need a good deal of 5/8" heater hose, i guess, and some clamps. i guess i should check compression when i get back in case it's the head gasket, so i'll rent a tester as well. (really hoping it's not that.) i'll need coolant and water. i'll want torx bits to open up the dash.

anything else you guys can think of? also, i have to drive to detroit (4 hrs) and back this week - will the bypass be reliable (assuming compression is fine) or should i just rent a hooptie?

if anyone spots a lonely white T5 on I-376 between downtown pgh and oakland, blow it a little kiss for me...