Hello All,

I have a 1996 850 GLT wagon with a 5 speed manual (non-turbo) with 330,000 miles on the odometer. Recently, I have noticed when I first start the car, especially if I have the defrost or heater on, I will smell a strong scent of coolant. I've noticed this experience on and off with this car over the years, but it seems particularly strong now. I've checked and the heater core and it is not leaking (the floor rug on the driver's side is bone dry). I have not noticed any leaks of coolant coming from the engine. After a little driving, the smell seems to dissipate.

I mentioned this to my independent Volvo mechanic, and he told me this was a design flaw with the heater core used by Volvo. The heater core doesn't leak, but it does "sweat" coolant which you smell when you initially start the car. This opinion was also shared with me by a sales representative with iPd. I have replaced the heater core on this car a couple of times over the years (when I detected coolant collecting in the rug on the driver's side). I have an identical 1996 850 GLT wagon, also a 5 speed manual, with 264,000 miles and I don't get the smell of coolant at all - though maybe sometime in the past I did experience it, and have just forgotten.

My questions are:

1) Is the smell of coolant a design defect sometimes experienced with the Volvo heater core?

2) If it isn't, any idea what is cause this smell and its source? As I said, after I drive the car a while the odor of coolant seems to drop off.

Thanks to all who reply.

Hugh

I switched to www.startpage.com for a search engine.
(I'm laboring with the idea that Google is way, over the top, too invasive.)

I entered "volvo 850 heater core, how-to"
Just ignore the first few ads that are presented for some good answers.

http://www.instructables.com/id/replacing-faulty-heater-core-in-Volvo-850-car/

There's some more links presented there faster than you can say "Go Red Sox!"

Cheers, Bill

BB,

Thank you for the directions. I printed them. Together with the "How to videos" I think I can tackle this job. Again, thank you for your help.

Hugh

It is time to replace the heater core again if the O rings are not leaking. The O rings cannot be reused. Depending on how long ago you replaced the core, just get a cheaper version on Ebay, there is one for less than $50, and get OEM O rings for it.

Klaus,

Thank you for your 3 replies. I guess I'm in denial about the heater core leaking. I remember seeing an excellent "How to" video" on how to replace the heater core. Yet as I write this, I can't recall where I saw it. Any suggestions?

Hugh

There are lots of videos, but they all use V70s. The 850 does not need to have the glove box removed.

Either lower the coolant level by draining the engine, or, clamp the two hoses that go through the firewall. No need to spill a gallon of coolant inside the car.

Both kick panels come out and tossed in the back seat. The black panel behind the carpet that covers the empty center dash space gets popped our and slides rearward to free up and come out.

Get a small supermarket bag that doesn't have holes in it to catch any antifreeze that will drip out. Remove the T25 screws that hold the plastic shell together. Remove the single T25 that holds the core to the piping that goes to the firewall. Remove the O rings. Remove the core with the plastic bag.

Take off the housing on the old core and put it on the new core, if not supplied. Put O rings on the metal piping. Slide the new core up and in. Connect the pipes with the T25.

Take off the hose clamps to the firewall. Start the engine and let it warm up until the engine fan kicks in, leave the cabin blower off to speed up the process. Turn the engine off and inspect the bottom of the heater core for leaks. Put everything back on, done.

If you like a slow show, this is pretty good:

http://www.bing.com/videos/search?q=volvo+850+heater+core+removal&FORM=VIRE3#view=detail&mid=DD54C877BB25102D596EDD54C877BB25102D596E

Klaus,

Thanks for the details and the link to the "How to Video". I viewed the iPd one and the other by the fellow called Robert Simpson, who is replacing the heater core on a T5. Between your comments and the videos, I feel confident I could do this repair. Thank you.

I have two '96 850s and a '99 XC, so the ability to replace a heater core may well become a "life skill".

Hugh

"Sweating coolant" , means there is a leak. The heater core is aluminum and as such is not porous. Sweating is usually attributed to the evaporator as it collects water vapor on its fins and is wet during cooling cycles.

The poor design of the heater core is mostly attributable to the lack of a cabin fresh air filter and the constant flow of coolant through the core. A core that has been replaced will also have stress on the firewall coupling, something that needs to be inspected on both sides of the firewall. I use a paper towel to find residue. Don't wait for the antifreeze to run down the center hump and into the floor mat.

Also check the cap for the overflow bottle. It doesn't age well, 10 year replacement cycle sounds good to me, as it could be either cracked or plugged up and allowing overpressure.

x2. Yup, it's a weak link.
"Sweating coolant" is nonsense. A heater core should not leak, period.
Replace it before you find fog on the windshield.
It's actually relatively easy if you're handy with tools.
I'm going to try to eliminate the firewall coupling when I do ours.
--
"Differences of opinions should be tolerated, but not if they're too different' - Sharon Craig

This looks real easy, especially the longer hoses:

http://www.matthewsvolvosite.com/forums/viewtopic.php?f=1&t=44948

Alschnertz,

Thank you for your comments and suggestion. Can you recommend any good "How to" video for showing how to replace a heater core?

Hugh

Koodo's for revamping the firewall coupling. There are 2 reasons for the current coupling. 1 - Incase of crash and engine submarining, coolant is not sprayed into the interior. 2 - Ease of manufacture. Number 2 is more important.

Except for sealing the firewall, running coolant hoses directly to the core would be quite simple and cheaper. Remember the engine can move, so there needs to be flexibility in the engine compartment, but not in the cabin where the core is fastened and rigid.