Hi,
I bought a 1999 s70 turbo and knew that the heater core was leaking coolant when the heater is on. I changed out the heater core with a heater core from ebay
Volvo Heater Core 850 S70 V70 C70 1994 Through 2000 Made in Europe 9144221 New | eBay

replaced it via RSPI's video with no issues. The coolant was brownish because it's old and the previous owner used some coolant leak blocker that was black.


now this is what happens.

No smells
> when Temp is on all the way to COLD
> when the vent is on fresh or recirculated

Smells like burnt plastic
> when the Temp is near HOT
> smells less like burnt plastic after 10 minutes and airing out.
> smoked a little earlier this week

I checked the cabin air filter and it was a little dirty, but not gross. Haven't changed a new one yet.

So I got a coolant flush and it's still the same smell.

Any ideas? Thanks

 

You should have washed the new core before installing it. Some new ones have a film of some sort on it and the smell will go away after a while.

The smoke is something that I never heard of from a heater core so it may be something completely different, perhaps the blower motor may be on its way out.

 

Thanks for posting. I will make a note on my video for people to wash it prior to installing.

They recently got a new supply of the cores so maybe something different is happening with their supplier. Please leave a message on their listing so they can try to have something done about it before they ship or buy.

 

Are you sure you didn't mess with any wiring when you were pulling stuff out? I find that burnt plastic smells in the passenger compartment are overheated wiring. A good thing to look at is the circulation fan resistor block and the wiring connecting to to it. the heater core itself will only get to the temp of the coolant which is less than 200 degrees. A coating could cause that but I would think that would be gone. You also mentioned smoke which is also a sign of a really hot electrical wire that is starting to melt.

 

At kwatt, I'll have to look into that..cuz a funny thing happened when i replaced the heater core...the dashboard lights came on for 10 minutes. then on wednesday i messed around the wires of the knee area of the drivers side and the dashboard lights worked for 30 minutes.

I smelt a burnt metal smell on thursday and the lights haven't worked very consistently.

 

If I recall correctly, didn't you have an issue with your dash lights some time back and you took the radio out or something along those lines and it worked????

You have a loose wire somewhere under the dash. You need to solve permanently or your going to end up with a melted wire or worse yet a fire. Some basics.... if you are smelling burnt plastic you are dealing with a high amp circuit. A 3 or 5 amp circuit is not going to generate enough heat before the fuse blows (imho).

Consider pulling the radio. It should make a big hole in the dash so you can look in there and see stuff. Same with the climate control unit. RSPI has some video on how to do most, if not all, of that.

Look for discolored wire. Most of the higher capacity circuits are yellow with some color or not or striping. Look near connectors for wires that all of a sudden look darker. When the plastic overheats it discolors. Look for discolored connectors. many are clear/white. If they are burnt a bit or have lost their rectangular shape, they have been very hot and melted some. Don't discount the climate control fan resistor block. If the dash has been out of the car, look at the connectors, if you can and make sure they aren't pinched between metal. I've seen where people use a connector to spread parts so they don;t squeak.

 

I should qualify the burnt smell is not fresh plastic smell when the heat is turned on. It's more like old rubber or old plastic smell.

That said, I will look for the Yellow wiring and any discoloration wires.

Thanks kwatt

 

Please do, you do NOT want this:

 

that's that image RSPI? I can't see it.

 

A picture of a 850 in flames.