Heater vs. defroster

sp1681 · Post by **sp1681** » 11 Feb 2011, 08:29

My 2000 V70 interior windows fog up when I have the heater on. Even after several minutes with car at temperature the windows never clear up. The only way to keep the windows clear is to have the valve set to defroster and the switch in AUTO as per manual. I just bought this car recently and use it for a daily driver and would like it a lot better if I could be warm. I've also noticed the car gets a musty smell when the heater is on as well. The car has 105K on it, just got the timing belt and water pump replaced. What's going on here? Thanks.

Post by **jblackburn** » 11 Feb 2011, 08:37

Your heater core is leaking and needs to be replaced.

It's a very easy, 30 minute do-it-yourself job. If you do end up taking it somewhere, don't let them tell you the dash needs to be removed.

https://www.matthewsvolvosite.com/2011/0 ... n-the-850/

sp1681 · Post by **sp1681** » 11 Feb 2011, 08:51

Thanks jablackburn for reply and link- another weekend project for me. If I were to go cheap would you recommend going with a used core or bite the bullet and get a new one?

Post by **jblackburn** » 11 Feb 2011, 08:57

Do it once and do it right - most are leaking by now anyway. An aftermarket heater core is $100 or so from FCP Groton; $130 for the OEM one. I went the OEM route, so I can't comment on how well the aftermarket one works.

Get the genuine Volvo O-rings for the connections into the core. The FCP O-rings leak like crazy, but their price on the core is good.

Post by **BEJinFbk** » 11 Feb 2011, 14:09

Before you start tearing it up and spending money,
Is there a lot of snow/rain where you are? Tracking it in?
If there's a lot of moisture in the car, your core may be fine.
The defrost setting activates the A/C and that pulls moisture out.
The heater will just keep blowing it around in the car.
Your windows wouldn't clear until that heater had been running for
a very long time. All the glass would have to get warm enough to
prevent condensation.

You may also want to check the condition of your cabin air filter.
If it's all clogged up, you'll have moisture and mustiness...

So check a few things first and maybe save some coin.
Loosing coolant? Is the carpet wet below the core?
Just some thoughts...

Post by **misha** » 11 Feb 2011, 17:32

This could be funny,but,is your "rec" switch in off position?

If it's on....that's the problem.Turn it off.

Post by **BEJinFbk** » 11 Feb 2011, 18:26

misha wrote:This could be funny,but,is your "rec" switch in off position?

If it's on....that's the problem.Turn it off.

But, what if I really DO want to Record?

sp1681 · Post by **sp1681** » 12 Feb 2011, 18:29

Thanks for the good replies, I'm going to check out the cabin filter and do some more investigating before getting into the core. I don't have wet carpet and don't think I'm losing coolant. The car came from MA and it came with a musty smell.
I do understand the REC switch being off to keep from recirculating the moist air. It's ok, I have a sense of humor too.
Thanks again for replies.