1998 V70 No heat MVSuccess! Heater core foam missing

[urmas97]

Hello!

I have I problem with my 1998 V70 2,5TD. The car has ECC. Since it is quite cold outside ( as low as -20C), I have noticed that I don´t get as much hot air in the cabin as I would like to. The air that blows from the vents is just lukewarm (although when the blower is not blowing so hard, it gets warmer). When I drove 200km yesterday, I could not take the winter jacket off because the cabin was not warm enough. The blower was blowing hard all the time (trying to achive the 24C that I asked the ECC to do), but no hot air was entering the car, just lukewarm.

The problem is not the thermostat, because the engine temperature is good. Also the problem is not about hot water not entering the heater core because both the inlet and outlet pipes of the heater core were very hot when I touched them. So, the hot water enters the heater core, but why there is no hot air in the car?

For the last few days I have searched the forums for solution and I came up with two possible reasons for that.

1. Shortly after buying my car I had to change the leaking heater core. I´m a bit worried that maybe the heater core that I bought might not be powerful enough to extract neccessary heat from the coolant. I´ve heard that some people have noticed that when they replaced their original heater core to an aftermarket "noname" heater core, then their cabin became colder than it was before. I did not have the opportunity to test the original heater core in cold weather so I can´t compare the new to the old one. Has anyone had problem like that with their car?

2. The second thing might be that the damper motors are not moving to the end positions (No error codes related to the damper motors). In my case, they might not be moving to the extreme where only heated air is directed to the cabin. Why I think that might be a problem is that my original ECC unit failed and I got an old one from the junkyard. I installed it and it started working properly. Now I have read the forums and found out that the damper motors need to be recalibrated after using an ECC unit from a different car. I have found a lot of information how to recalibrate the damper motors on 850s, but haven´t found anything that talk about how to do it on 1998 V70 with OBDII. Does somebody know if there are instructions somewhere about my car?

And for those who see that I could easily short out which one of these two is the problem, I can tell that I can´t sort it out because when I changed the heater core, it was not that cold outside to see any difference between the new and old one. Shortly after replacing heater core I changed the ECC and at that time it was also not so cold outside to see any difference.

Hopefully some of you has some good tips for me!

Urmas

[Ozark Lee]

I have encountered heater cores that are slightly narrower than the originals and they leak air around the sides if additional weatherstrip material isn't added to them. It isn't that the core isn't "powerful enough" it is more of an issue of cold air leaking around it and mixing with the heated air.

One other thing to check is that you have your fresh air vent on the center upper dash vents turned off. That makes a huge difference by itself.

...Lee

[urmas97]

I have encountered heater cores that are slightly narrower than the originals and they leak air around the sides if additional weatherstrip material isn't added to them. It isn't that the core isn't "powerful enough" it is more of an issue of cold air leaking around it and mixing with the heated air.

One other thing to check is that you have your fresh air vent on the center upper dash vents turned off. That makes a huge difference by itself.

...Lee

The fresh air vent is turned off, otherwise it would be really cold.

The cold air leaking around the heater core is an interesting idea. When I changed the heater core I remember that there was somekind of a soft isolation material that had sticker on one side. I´m pretty sure I used it in the correct mannaer. Unfortunately I did not take any pictures and to find out if I misplaced it would require taking the heater core apart again. But maybe it is something I need to do, when not finding any other solutions.

[abscate]

It isn't hard to drop the core out of the car - the dash can stay in place.

[urmas97]

I solved the problem. Took it out and saw that indeed, the heater core was narrower than the plastic casing. It was about 5mm of empty space on both sides. I added some soft foam like material to the sides and now it works perfectly. What a pleasure to drive in the warm car

Thank you Ozark Lee!