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Tue Aug 19, 2008 6:31 pm

Today leaving work I accidently left my engine lid open and drove about 20 miles before making a stop and realising. What I did notice on the drive though was that my oil temp was running about 15 degrees colder than normal. I have been told opening the decklid only interferes with vws design with the air scoops and actually makes the engine run hotter do to pulling in hot exhaust air via the vortex affect. I have all stock tin in place and all seals. I do notice that when working on the bus the horizontal part of the apron gets extremely hot from the exhaust header (cb performance quiet one). I think this must increase engine compartment temps considerably I bought some exhaust wrap tape today that I will put on this weekend to see if that makes a difference. anyone use that stuff?

Tue Aug 19, 2008 6:47 pm

You can also try taking off the apron and making/attaching a heat shield on the underside to deflect some of the heat. General rules of thumb like running with the decklid open go out the window when your bus deviates from stock too much. You might be running a little too hot with your setup to begin with, who knows.

Tue Aug 19, 2008 6:56 pm

my motor is pretty much stock except the exhaust and as of yesterday a maxi pump 3 with remote oil filter. I was thinking about adding a heat sheild or even just gluing some aluminium foil under the apron

Tue Aug 19, 2008 8:25 pm

I have used the exhaust tape and over time it will just hold moisture and speed up the rusting process.

Tue Aug 19, 2008 10:02 pm

i personally think that when you are "blowing" down the highway, like when you leave work and travel 20 miles, the more air the better. right? your engine is air cooled. under a load--as in driving around town, in traffic--the scoops and their location allow the engine to bring in (via the fan) relatively cool air and literally blow it over the beast and get rid of heat. just remember that Z Germans did an extremely good job at getting and air cooled engine to work at all! check out raby @ aircooledtechnology...(somebody)... i don't know how to post a link, but i do know how to keep a bus from cooking in lake havasu az and it's not hard.

Tue Aug 19, 2008 10:25 pm

I myself have heard from some pretty reputable ACVW guys that leaving the decklid (bus) cracked about an inch or so can shed as much as 10-15 degrees CHT temps.

Wed Aug 20, 2008 12:40 am

orangesuper wrote: Today leaving work I accidently left my engine lid open and drove about 20 miles before making a stop and realising. What I did notice on the drive though was that my oil temp was running about 15 degrees colder than normal.

You sure it wasn't running cooler because of your new full flow filter.

Thu Aug 21, 2008 6:09 pm

It does run a few degrees cooler with the full flow filter but not the drastic difference that the gauge showed with the engine compartment door open

Thu Aug 21, 2008 6:14 pm

The air density could have also changed, changing the air/fuel mixture of your carb(s)

Thu Aug 21, 2008 8:19 pm

I leave the T4 theory out of this, but on a T1 pushing a bus, pop the deck lid completly open and you will find out that people who say it won´t help cooling the engine while continually runing, don´t know nothing about these beasts, just because it might not be legal to drive a car in the U.S with a door open, it don´t mean you got to go telling other people not to do it, on the basis that their engine will run hotter, yeah right... :roll: you might want to stop wasting money on those fancy CHT gauges and likewise and start knowing you vehicle better. Eaven the water cooled bays around here get the cooling efect from a engine compartment openden all the way, a lot of people around here would have a heart atack if they see this, or just think everybody else is stupid....

just my 0.20
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Thu Aug 21, 2008 8:33 pm

El_Güero wrote: you might want to stop wasting money on those fancy CHT gauges and likewise and start knowing you vehicle better.

How will you know your vehicle better without a gauge that gives you simple data? Are you just going to pull the dipstick and touch the oil to see if it is hot?

Thu Aug 21, 2008 8:53 pm

Take a drive around Mexico city and you will see a high percentage of Combis running with their lids open. An open lid is also good to keep the local mounties from seeing what license plate number you have in case you are driving in the ciudad on the wrong day.

Thu Aug 21, 2008 8:59 pm

Quote: How will you know your vehicle better without a gauge that gives you simple data? Are you just going to pull the dipstick and touch the oil to see if it is hot?

How will you know your data is right, if your having nighmares just to find the right location and best device to put in, the "ring seating problem" you read all the time in all those CHT makes you wonder, and what about getting a right oil temp reading, you have to mess around with the sender location etc etc. Interesting you mention the dipstick, a quick touch just to feel if you can grab it will tell you more sometimes.

Thu Aug 21, 2008 9:08 pm

Quote: Take a drive around Mexico city and you will see a high percentage of Combis running with their lids open. An open lid is also good to keep the local mounties from seeing what license plate number you have in case you are driving in the ciudad on the wrong day.

that use to be a trick, but then again, all vehicles in México have a copied sticker of the license pate number, glued to the rear glass, the sticker includes a color code wich will tell you what day is your day, so cops don´t look for number, they actually search for a tiny litle colored square, things are waaaay different than they used to be.

Thu Aug 21, 2008 9:51 pm

VW wanted that lid closed for some reason, they even sealed it up real good.

The only thing that jumps out at me is, if you leave the lid open the engine could be drawing in exhaust gases, road dirt/dust and hot air trying to leave from under the car. The reason I think this is, I see after driving my Bus for quite a while that the lid area gets dirty from exhaust gases...

Deron.

Thu Aug 21, 2008 9:56 pm

Come to think about it, the scoops for the engine compartment are purposely put real high on the Bus. Could be cosmetic, but they would pick up less road dirt and dust up there.

Deron.

Thu Aug 21, 2008 10:18 pm

Quote: Come to think about it, the scoops for the engine compartment are purposely put real high on the Bus. Could be cosmetic, but they would pick up less road dirt and dust up there.

Thats true. in the 1.8 watercooled version, the air filter is confined in a cylinder shaped box wich has its normal inlet conected to a large periscope thats bolted all the way to the top of the left scoop.

Thu Aug 21, 2008 10:32 pm

El_Güero wrote: I leave the T4 theory out of this, but on a T1 pushing a bus, pop the deck lid completly open and you will find out that people who say it won´t help cooling the engine while continually runing, don´t know nothing about these beasts, just because it might not be legal to drive a car in the U.S with a door open, it don´t mean you got to go telling other people not to do it, on the basis that their engine will run hotter, yeah right... :roll: you might want to stop wasting money on those fancy CHT gauges and likewise and start knowing you vehicle better. Eaven the water cooled bays around here get the cooling efect from a engine compartment openden all the way, a lot of people around here would have a heart atack if they see this, or just think everybody else is stupid....

just my 0.20

:-s water cooled bays... :-k

Fri Aug 22, 2008 1:02 am

Quote: water cooled bays...
TOTALLY ROCK!

(well, I like to think mine does, anyways....) :wink: