TheSamba.com :: View topic - Engine Cooling and Cabin Heating System Tutorial

Fri Oct 01, 2010 5:31 am

I bought a new fastie in '70, it would cook ya in just a few blocks. Had a baja, drove it for 6-7 yrs. hadda keep the ice scraper handy for the inside of the windows :lol: These things will work when all the parts are there & function properly. Excellent writeup Paul !!!!!!!!!!!!!!! JP

Fri Oct 01, 2010 6:18 am

You should submit this to Hot VW or some other magazine for publication or make print outs available that VW shops could hand out to new owners...The majority of newbs out there could use this...when I was a newb, I figured it out on my own but it took a long time, a few mistakes and a few reads of Bentley and Haynes to get it right...(and I'm a graduate Engineer by trade....)

Fri Oct 01, 2010 8:16 am

tele68 wrote: You should submit this to Hot VW or some other magazine for publication or make print outs available that VW shops could hand out to new owners...The majority of newbs out there could use this...when I was a newb, I figured it out on my own but it took a long time, a few mistakes and a few reads of Bentley and Haynes to get it right...(and I'm a graduate Engineer by trade....)

This was my main reason for writing the article. I have owned my car since 1995 and read as much as there is to read. I own the Idiot book, the Bentley, the Haynes, I've read magazine articles and tidbits on the web, and I have never seen an article that has ever explained the system in it's entirety. Pieces here and there, like "check the cables", or "make sure the heater boxes don't leak", that's about it. I work at a Cadillac dealer, and the first thing to do when searching for ANY problem is to understand how a system is supposed to work when it's not broken. With a good understanding of how it works, one can more readily identify something wrong when it doesn't. Many of the Beetles one can find for sale now have been pulled out of swamps, butchered by previous owners with more "Knowledge" than the folks at VW, rusted badly, have missing parts, etc. A new-comer would have no knowledge of what is supposed to be there without an article to clearly demonstrate how it's supposed to be. Plus the "conventional wisdom" on the street clearly states that Beetles have no heat, so someone new to the hobby may overlook all kinds of things due to unintentional ignorance, and the assumption that a heating system doesn't exist.

Fri Oct 01, 2010 1:18 pm

I just added an explanation of the OE and new style thermostats.

Tue Oct 05, 2010 9:49 am

Added pics and explaination of flaps. Thank you, mnussbau, borrowed your pic from the gallery.

Tue Oct 05, 2010 12:17 pm

A great tutorial!

Wed Oct 06, 2010 10:11 pm

Those heater testimonies sound great for southern CA.
I've had lots of Bugs with fully functioning heaters. I've also driven them through fully functioning winters. They had problems. Being able to see out comes first, but with all the heat directed at the defrosters, the windshield might never clear off, and the interior never got comfortable. THEN I found the secret ! Start with the defroster on full, and race the engine a little so you can feel the airflow better with your hand over the defroster vent. Next, open the rear seat vents SLOWLY until the defroster flow decreases JUST A LITTLE. The heat that's now blasting out from under the rear seat is much hotter and faster than what squeezes out of the defroster vents, and it's perfectly aimed at the center of the interior. The whole interior gets warmer faster, AND defrosting is greatly accelerated because of this. Then leave that rear seat lever alone.
Depending on the year of your car, the front floor vents might benefit from similar tweeking.

Thu Oct 07, 2010 1:14 am

HFOAIE wrote: Those heater testimonies sound great for southern GERMANY.

Fixed it for you.

Thu Oct 07, 2010 8:06 am

HFOAIE wrote: Those heater testimonies sound great for southern CA.
.
works well here in the Blue ridge mountains of Va....

Thu Oct 07, 2010 10:53 am

HFOAIE wrote: Those heater testimonies sound great for southern CA.
I've had lots of Bugs with fully functioning heaters. I've also driven them through fully functioning winters. They had problems. Being able to see out comes first, but with all the heat directed at the defrosters, the windshield might never clear off, and the interior never got comfortable. THEN I found the secret ! Start with the defroster on full, and race the engine a little so you can feel the airflow better with your hand over the defroster vent. Next, open the rear seat vents SLOWLY until the defroster flow decreases JUST A LITTLE. The heat that's now blasting out from under the rear seat is much hotter and faster than what squeezes out of the defroster vents, and it's perfectly aimed at the center of the interior. The whole interior gets warmer faster, AND defrosting is greatly accelerated because of this. Then leave that rear seat lever alone.
Depending on the year of your car, the front floor vents might benefit from similar tweeking.

Great tips! I wish I had rear heat outlets!

Really, the poor defrosting is more a product of not having air conditioning than having poor air flow. Most modern cars run the a/c a little when defrost is selected. This is because a/c dehumidifies the air before it is thrown at the windshield, which wicks away the moisture that causes fog/frost, and deposits it as condensation on the face of the evaporator core. We had a Cadillac STS last winter in the shop with a recirculation door that was stuck so the blower kept pulling in humid air from the floor. The windshield would actually get worse the longer the defroster was on. This is why defrost in a Beetle is sometimes helped by opening a vent window when driving. The air outside in the winter (albeit cold) is usually dryer than our breath, which accumulates in an air tight car.

Thu Oct 07, 2010 10:56 am

rain x my friends, who needs a defroster then. I would die without it in my 53 f100

Thu Oct 07, 2010 12:28 pm

chappys4life wrote: rain x my friends, who needs a defroster then. I would die without it in my 53 f100

Junk. Get PPG Aquapel.....RainX on steroids. (Although I wouldn't use any of these products on interior glass surfaces.)

Thu Oct 07, 2010 7:40 pm

In my 76 standard beetle when it gets to be winter(months below freezing) here I modify my heater system a little bit. I leave the front floor vents shut (disconnect cable also) and run a section of hose from my rear heat vents to under my front seat. When driving I flip both levers. The heat on gives my defrost all the heat, the left lever heats up my cabin. In winters where we have highs in the single digits I'm plenty warm even with a slight dash leak and still have pretty decent defrost.

Fri Oct 08, 2010 12:52 pm

wow thank you so much for all this great info! I have a merged exhaust with no heater boxs, how do i check to make sure the flaps are open?

Mon Oct 11, 2010 12:44 pm

Manstache wrote: wow thank you so much for all this great info! I have a merged exhaust with no heater boxs, how do i check to make sure the flaps are open?

Which flaps? The flaps in the fan shroud?

Sun Oct 17, 2010 7:32 pm

Great info
I recently got a 74 Super that has been hacked up. So I will need to crawl under and look for the thermostat.

Thanks Again
Brett

Tue Oct 19, 2010 5:17 am

Congrats to the author!

Soon I have to crawl underneath my bug to set the heat "on" by opening the flaps, as both control cables are broken. Otherwise, my heating system works pretty fine[/quote]

The control cables are 10 bucks and even my grandma could replace them in an hour! Easy fix!

Tue Oct 19, 2010 10:09 am

Adding to the kudos.... great write-up!

Wed Oct 20, 2010 2:38 pm

My heater works down to 40 degrees too, which takes care of spring and fall in MN. Then we have winter, and 20 below zero. Never had the heater produce any warmth at that temp.

Wed Oct 20, 2010 2:45 pm

we don't get real cold temperatures here, we can hover around zero for a bit, but I still get too much heat at that temperature...gotta love a well working, as designed, system....even with all my rubber seals falling apart causing a draft... :wink: