Preheat Hose Locations (Beetle)

Rickles · Post by **Rickles** » Sun Feb 07, 2016 12:10 pm

I may not have searched for the correct terms; didn't find anything.

Were there two routing versions for the preheat hose from the air cleaner?

One version with a hole next to the large fresh-air hose on the left side of the rear engine cover tin (this is what I remember on my two '66s from years ago), and another version where the hose is routed to somewhere on the left front of the engine (I've seen this in pictures). If this is the case, then are there two version of the heater box?

I've looked at pictures of replacement rear engine covers at a couple of on-line parts places, but none had the hole for the preheat hose. I guess they are meant to be more "universal" this way?[/img]

Rickles · Post by **Rickles** » Sun Feb 07, 2016 7:29 pm

Maybe I've answered my own question. During the restoration and engine rebuild, they may have used the older design because they couldn't get the regular '66 pre-heat tube and tin. Just my guess anyway.

Digger89L · Post by **Digger89L** » Mon Feb 08, 2016 4:20 pm

I have two 'barn find' VWs .....the 66 that I'm rebuilding, and a 64 that I've since sold off to fund the 66 project. The photo of the engine in the 66 shows the same set up as the first pic you posted, (except that the hose is missing) ...and the photo of 64's engine shows the hose going around to the back of the engine. So ...I'm assuming the hose at the front is correct for 66 (its shown that way in the Owner's Manual). Perhaps someone swapped in an older engine on yours ...or older tins.

h~moto · Post by **h~moto** » Mon Feb 08, 2016 4:21 pm

On May 4, 1966 at chassis #116852850 (eng # F0 767046), the carburetor preheating was changed from taken from the underside of the cylinder head to taken from the left heat exchanger.

I think `67's might have switched back to using heat from the underside of the cylinder head but pulled it from the left and the right side (don't quote me on this).

Rickles · Post by **Rickles** » Mon Feb 08, 2016 5:31 pm

Thanks, both. The chassis is 11682... on the one I'm looking at, so I guess it should have had the rear mount next to the fresh-air hose. I'm also guessing they couldn't get the correct sheet metal during the rebuild which is why it was switched. The owner told me today he's noticed some hesitation until it warms up but runs perfectly after that. They rebuilt the carb. again to no avail. I guess the hose placement has nothing to do with it, then. He said the heat riser tubes get good and hot.

Thanks again for the good info.

Blue Baron · Post by **Blue Baron** » Sat Mar 05, 2016 1:44 am

I think H~moto is right. My late '66 has the hose going to the left heater box, though I've seen this arrangement on some early cars as well. Perhaps it was a modification for colder countries? Whatever it was, it's a bad idea to pipe such hot air back into the engine. I have mine hooked up for looks, but I have the hose blocked off. (I don't really need it living in Forida.)

darzoom · Post by **darzoom** » Mon Mar 07, 2016 7:10 am

Just to agree, Page 42 of the original owners manual shows like your first photo. Except the tube is the black cardboard style and not shiny.

Digger89L · Post by **Digger89L** » Sun Apr 03, 2016 12:37 pm

" Whatever it was, it's a bad idea to pipe such hot air back into the engine." This is not the case if your system is working correctly: once the engine warms up, the air cleaner flap will open, allowing cooler, fresh air into the air cleaner, and at the same time blocking off the hot air coming up thru that tube from the manifold area. As someone said on the forum, if the German engineers of the day designed and built things the way they did, they knew what they were doing and did it for good reason.

darzoom · Post by **darzoom** » Tue Apr 05, 2016 7:09 am

Not to start a fight, But, the engineers at VW were not GODS. I agree they designed the Bug a certain way for the time it was built. But, things have changed (materials, fuel, oils etc.) along the way and there are now better ways to make the VW better. If that were not the case, VW would still be producing the same car that was originally introduced in the 40's.

Now if the point is "Stock or Not" that is a personal preference.

Blue Baron · Post by **Blue Baron** » Tue May 03, 2016 1:04 am

Digger89L wrote:" Whatever it was, it's a bad idea to pipe such hot air back into the engine." This is not the case if your system is working correctly: once the engine warms up, the air cleaner flap will open, allowing cooler, fresh air into the air cleaner, and at the same time blocking off the hot air coming up thru that tube from the manifold area. As someone said on the forum, if the German engineers of the day designed and built things the way they did, they knew what they were doing and did it for good reason.

That was probably me. Anyone who has read much of what I post here knows I'm about as orthodox as they come, and bow down to the krauts in white coats, but if your original heater is in any kind of good condition like mine is, you'll be piping red hot air into your engine every time the car sits and idles, because that flap only opens when the engine begins to accelerate, or if you go back there and lock it open with the little lever on the air cleaner. The fact that they couldn't make up their minds, and switched it around a few times, should indicate that they didn't get it resolved until later on. But the biggest drawback of the whole thing is when the hose rots or falls off the heater box connection and is no longer connected to the air cleaner. Then it pours hot air into the engine compartment and there's no shutting it off unless you can get back there and plug it.