2000 V70 - Low heat from HVAC

[rolsen11]

Now that the arctic January cold has finally hit, I've been wondering about the lack of hot air my car has always had since I've bought it. During the winter the car gets barely warm enough to be mostly comfortable at best. And this takes along time, usually only gets to that point at the end of my 30 minute commute.

I don't believe that a Volvo would output that little amount of heat from factory so I assume something is wrong. My hypothesis is that the heater core is clogged since the previous owner brilliantly decided to unload a bunch of copper stop leak into the cooling system. So much so that years later when I replaced the overflow resevoir it still had a thick layer of copper sludge sitting at the bottom.

However, I would like to gather other opinions on what the issue could be so that I know what else to look for. I would like to measure the heat output at some point but I don't have the tools for that at the moment. Considering I can get a Nissens heater core for for about 30 bucks I'm probably just going to get a new one on order anyways.

[scot850]

There are 3 things that come to mind:

1) No thermostat fitted - car may never get up to temp and will run cool as well as the heating system
2) Blocked heater core - Not common, unless plain water has been used or someone has used liquid head gasket fix that can plug that and the engine radiator as well
3) The heater system servos are not directing the hot air to the cabin. If both sides are affected there are 2 places I'd suggest checking:
a) The cold air flap behind the cabin heater fan is not stuck open. There is a plastic arm that breaks. From memory it leaves the cold air intake on full cold.
b) The air blend servo motor is not working correctly. On a 2000 P80 it is hard to get too. It is fitted up on the RHS of the steering column.

Neil.

[rolsen11]

There are 3 things that come to mind:

1) No thermostat fitted - car may never get up to temp and will run cool as well as the heating system
2) Blocked heater core - Not common, unless plain water has been used or someone has used liquid head gasket fix that can plug that and the engine radiator as well
3) The heater system servos are not directing the hot air to the cabin. If both sides are affected there are 2 places I'd suggest checking:
a) The cold air flap behind the cabin heater fan is not stuck open. There is a plastic arm that breaks. From memory it leaves the cold air intake on full cold.
b) The air blend servo motor is not working correctly. On a 2000 P80 it is hard to get too. It is fitted up on the RHS of the steering column.

Neil.

The car does have a thermostat, it was one of the first things I did to the car when I bought it since the old one was sticking mostly closed.
I think item 2 is probably what's wrong, there was so much stop leak in the reservoir that I can safely assume there is a bunch of it pooled up in the heater core too.
Items 3a and b are something I can certainly try to take a look at. It will have to wait a bit though, it's currently a very balmy -24F with a -51F windchill.

I am not going outside if I can help it

[rolsen11]

Measured the heat output on my way to work this morning, car up to temp, exterior temp ~25F. Center vents ~112F, side vents ~130F. Too low, even at a warmer exterior temp the car never got hot on the inside.

New heater core arrives tomorrow, plan to replace this weekend. I also ordered a new actuator arm for the air intake flap just in case, will replace as necessary when I get in there for the heater core.

Reference:
viewtopic.php?t=107507

[rolsen11]

The job is done! There wasn't any obvious copper stop leak in the old core like I thought there might be. I might try to flush the old core with water just to see what happens. It's definitely not the original heater core, but I don't know how old it is or what brand it is, appears to have been a cheap no-name replacement.

Upon removal of the glove box, I discovered that the recirc damper arm was not attached to the actuator. However, when I pulled the arm towards me and got a good picture of it, I saw that it wasn't broken. It actually looks like a new part. Somehow it fell off of the square drive of the actuator, maybe due to vibrations. I put the arm back onto the actuator and viola, the recirc function works again.

Either way, the car now has nice, HOT heat. Have to give a big kudos to the Volvo engineers for making the heater core an accessible part.

Access panels removed

Old heater core removed

New Nissens heater core

New Nissens heater core

New heater core installed

Arm disconnected from actuator

Old recirc arm not stripped out