96 850 GLT - Steam/Vapor coming from Vents

Your heater core has failed, you'll have to get that replaced before it makes a real mess. It probably won't blow up, but it will leak coolant into your interior and it's not good for you to breathe the vapor either.

As James says, the heater core has failed... the symptoms are unmistakable. (I'm assuming the vapor had the sweetish odor of antifreeze.) Unfastening the heater hoses and plugging them will allow you to drive it until you can get the heater core replaced if there will be a long lead time, but then you will have no heat and no defroster.

If you drive the way it is you risk warping the cylinder head.

Mike

Dear Listers,

I noticed that the coolant was low, so I added to the reservoir, started the engine, left the cap off and went to do something else, while the engine was warming up. I come back to see that the overflow reservoir is boiling happily away. So, I shut the engine down, replaced the cap and restarted the engine and left to go finish something else.

When I came back steam/vapor was coming from the air vents, so selected a higher setting for the fan. It blew the vapor away temporarily, but I could see vapor still coming out of the side vents of the dash, where it goes into the door panel. (The driver's door was open). I shut the fan down and the vapor came seeping back through all the vents and it was quite hot.

The ambient temperature was about 20 C (68 F) and the thermostat setting was on 72 degrees and the A/C compressor switch was off and the recirculation toggle switch was off. (Light was not on and fresh air was coming in).

What gives? Can I drive this car without the cooling system blowing up?

Thanks for any advice.... As James says, the heater core has failed... the symptoms are unmistakable. (I'm assuming the vapor had the sweetish odor of antifreeze.) Unfastening the heater hoses and plugging them will allow you to drive it until you can get the heater core replaced if there will be a long lead time, but then you will have no heat and no defroster.

If you drive the way it is you risk warping the cylinder head.

Mike

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Replace the thermostat and ect sensor below the t-stat also. Water should not be boiling out of the coolant bottle, even with the coolant cap removed. The electric cooling fan should have turned on instead. The coolant boiling out in probablly due to a stuck closed t-stat. The extra water pressure could have caused the heater core 2 fail and start leaking. The heater core is probably $300 to $400 and about

Dear Listers,

I noticed that the coolant was low, so I added to the reservoir, started the engine, left the cap off and went to do something else, while the engine was warming up. I come back to see that the overflow reservoir is boiling happily away. So, I shut the engine down, replaced the cap and restarted the engine and left to go finish something else.

When I came back steam/vapor was coming from the air vents, so selected a higher setting for the fan. It blew the vapor away temporarily, but I could see vapor still coming out of the side vents of the dash, where it goes into the door panel. (The driver's door was open). I shut the fan down and the vapor came seeping back through all the vents and it was quite hot.

The ambient temperature was about 20 C (68 F) and the thermostat setting was on 72 degrees and the A/C compressor switch was off and the recirculation toggle switch was off. (Light was not on and fresh air was coming in).

What gives? Can I drive this car without the cooling system blowing up?

Thanks for any advice....

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Depends, the part is $171 online, the job is quite labor intensive though, figure 4-6 hours of shop time. Seems like I've heard it quoted at $600-$800 to have it done at an independent shop but you'll want to call and find out. If you're a reasonably capable home mechanic you can do it yourself but in most cars essentially the entire dashboard has to be removed.

Anything more then 3 Hours labor then find another repair shop the dashboard does not have to come out to do the heater core Glenn

I guess they improved that on the 850? I know a heater core on a 240 is a *major* job, having spent the better part of a day on one. Thankfully I haven't had to find out on any newer cars yet but it doesn't look real easy to get to on my 740 either.

The 740 is no easier than the 240 (haven't done a 240, but I'll take your word!). The first time it took me three days because the Haynes manual indicated the dash didn't have to come out. Technically, I suppose it doesn't, but it's really *much* easier to remove the dash. There is no hard part that way (just a whole lot of tedious parts), but the passenger compartment looks like an explosion in a wire factory by the time you get that far.

Glad to hear about the 850.

Mike

I just replaced the core on my 850 - an hour and a half and the new core was in place.

Well, fellow listers, here's the scoop:

I also made a stop at a Volvo, sort of "boutique" repair shop and asked similar questions. Well, lots of drama here. "Oh, bubbles coming from the reservoir - well, that's a sure sign of a blown head gasket".

Really now. Could it possibly be a stuck thermostat?

"Oh no, we see this kind of thing all the time in an 850. Yes, we just did one with a similar problem".

Uh huh. And what was the cost?

"I can look that up, yes, here it is... about $1300.00, let's see $340 for the heater core...."

Ok, thanks for the insight, I'll think about this.

"Shall we send a tow truck?"

No, I need to consider what to do with the car.

So, I check on E-Bay and get a core for $109.00. I call another guy, who's done work for me and my wife and explain the problem.

It turned out to be the heater core, as part of the problem. Second part is a stuck thermostat. Replaced both. Car runs perfectly.

Total cost: $109 for heater core, $200 for labor and another $20.00 for the thermostat, including labor = $329

My thanks to you all for your advice and guidance.

pkallis wrote: