Cooling System

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NO to K&N

Read this first from TDI Club about Silica

Airbox Filters

Using a proper filtering air-box & filter is critical to a proper running engine. Knowing your engines requirements really helps suiting an airbox!

1.6na (CS) - 210cfm

CS Air Filter & Cross Reference)

There's no real benefit to upgrading the 1.6na engine if you have it intact. It won't be till you upgrade to a different engine for when you need to look into it.

1.6td (JX) - 125cfm

These engines came with a 125cfm airbox & filter

JX Air Filter & Cross Reference

1.9td (AAZ)

These generally use the same as the 1.9tdi (1z/AHU/ALH) counter-parts.

1.9tdi (1z/AHU/ALH) - 210cfm

These engines came with a 210cfm airbox & filter

AHU Air Filter & Cross Reference

ALH Air Filter & Cross Reference

Airbox Intake Routing

A good layout for the Airbox & Intake is shown below for turbo diesel setups with an IC in the rear PS pillar. If you relocate your starter battery and clear that area up for an airbox, you got a great path of air.

  • Airbox to most turbos (K14,K03,GT2052) will be 2.25” or 57mm that includes the 2.25”x1”x2.25” tee or better termed “57mm BOV” in ebay. The BOV tee is preturbo post airbox that the CCV dumps into
  • Most Turbos (K14,K03,GT2052) to IC will be 2.25” or 57mm and IC to Intake manifold is 2.25” or 57mm

Air comes into the passenger side vents and feed air into the airbox of your choosing. The driver side air vents bring air into the A2A IC placed.

IC Intake Routing.jpg

Do NOT use a K&N air-filter for your air-box at all costs. It doesn't filter well enough for the TDI. More information here

Airbox Options



Donaldson 2.5” - 175CFM filter

Donaldson 3.0” - 215CFM filter

These are the Donaldson filter housings often used.

90° Outlet

  • G065411 with 2.5" inlet & outlet ports @ 175CFM
  • G065433 with 2.5" inlet & outlet ports @ 175CFM
  • G070018 with 3.0" inlet & outlet ports @ 215CFM
  • G070020 with 3.0" inlet & outlet ports @ 215CFM

Straight Outlet

  • G065424 with 2.5" inlet & outlet ports @ 175CFM
  • G065432 with 2.5" inlet & outlet ports @ 175CFM
  • G070017 with 3.0" inlet & outlet ports @ 215CFM
  • G070019 with 3.0" inlet & outlet ports @ 215CFM

The reason for the starter battery relocation was for the Donaldson G065433 air-box with the bracket p/n H0084412 or H008444

I wanted to get the intake routing as direct as possible with my setup.

Using a passenger fabbed snorkel coming into thje passenger side, putting the Donaldson as shown below, makes it way easier and direct for the hoses.

NOTE: I had to remove the tabs off the old DV snorkel and those foam bits. It was then able to fit into the passenger side with some wiggling effort with the 3" hose. It WILL go, but be patient and take your time. For securing the hose to the snorkel use Rescue Tape!


Installed view without hoses, yes the clips are functional! The lower is a little bit tight, but it works!

Betsy Intake Box-a.jpg

Betsy Intake Box-d.jpg

This gives some idea of how much hose clearance I'll have. The taillight is installed in the last photo to get a reference:

Betsy Intake Box-b.jpg

Betsy Intake Box-c.jpg

This is the snorkel and 3" hose attached. It was a bit to work the 3" around the snorkel, but it WAS possible!

DV snorkel 3inch tubing.jpg

This is the snorkel wrapped with Rescue Tape to attach the hose. This is the BEST tape to use compared to "duct-tape". No substitution for this project!

DV snorkel rescued.jpg

This is how the snorkel will look when test-fitting. You'll need to remove the tabs/foam for it to fit

DV snorkel moved ps.jpg

Snorkel hose is now attached to the Donaldson as shown in this photo looking in from the rear light

Betsy Intake Snorkel Hose Routed.jpg

The red one is going to the turbo. It's a tight fit! But it's doable! It's 2.5" on the Donaldson side to 2.25" on the metal pipe

Betsy Intake Snorkel Hose Routed-red.jpg

Jaguar XJ6 1979-87

I haven't done this personally, but others have. Here are some photos

Jaguar XJ6 Airbox.jpg

Installed in a vanagon

Jaguar XJ6 Vanagon Airbox Install.jpg


I'm currently in the process of making a TDI Carbon Fiber air-box that wlil go where the Donaldson goes. The best airbox for the TDI engine! Keep posted ;)

Airbox CFM Math

First let's put some referenes up front.

Bar Pressure

Let's get some basic numbers

1 bar of pressure is 14.5psi
1.25 bar of pressure is 18.1psi
1.50 bar of pressure is 21.7psi
1.75 bar of pressure is 25.4psi
2.00 bar of pressure is 29.0psi

Air flow Calculation


Widman International CFM Calculator



Displacement: 1896 cm3 or 115.7 cu-in

Air Capacitycfm = (displacement x RPM) ÷ (1,728 x 2)

Note: Air capacity is a function of displacement (volumetric capacity) and engine speed (RPM). The displacement is divided by 1,728 (the number of cubic inches in a cubic foot) to convert it to cubic feet. The RPM is divided by 2 because the engine only intakes on every other revolution. The formula can be simplified as follows:

Air Capacitycfm = (displacement x RPM) ÷ 3,456

Let’s calculate the airflow requirement for a stock AHU VW TDI engine of 115.7-ci with a torque peak at 1900 rpm and a maximum engine speed of 4000 rpm.

NO BOOST examples:

Torque peak:

CFM = (115.7 x 1900) ÷ 3,456 = 63 cfm at the torque peak

Middle 3k:

CFM = (115.7 x 3000) ÷ 3,456 = 100.4 cfm at the torque peak

Power peak:

CFM = (115.7 x 4000) ÷ 3,456 = 133.9cfm at the power peak

18psi max boost'

  • 1.2bar = 18psi

Torque peak:

CFM = (115.7 x 1900) ÷ 3,456 = 63 cfm at the torque peak x 1.2bar = 75.6cfm

Middle 3k:

CFM = (115.7 x 3000) ÷ 3,456 = 100.4 cfm at the torque peak x 1.2bar = 120.48cfm

Power peak:

CFM = (115.7 x 4000) ÷ 3,456 = 133.9cfm at the power peak x 1.2bar = 160.68cfm

29lbs max boost - crazy fucks!

  • 2.0bar = 29psi

Torque peak:

CFM = (115.7 x 1900) ÷ 3,456 = 63 cfm at the torque peak x 2bar = 126cfm

Middle 3k: :CFM = (115.7 x 3000) ÷ 3,456 = 100.4 cfm at the torque peak x 2bar = 200.8cfm

Power peak: :CFM = (115.7 x 4000) ÷ 3,456 = 133.9cfm at the power peak x 2bar = 267.8cfm

Coolant System

NOTE: Before you start disconnect the negative wire to the starting battery!

NOTE: This assumes your water-pump & thermostat are good, if not that should be replaced! If not here you go for p/ns ETKA If you're doing a conversion soon, may want to hold off on the water-pump till the new engine ;)

The van is HOW old? And how important is a coolant system to a functioning engine? The answer is VERY to both questions!

Revamp your coolant system!

  • New Radiator p/n 068-121-253E
  • New Radiator Fan p/n 165-959-455AM
  • New Radiator Temp Switch stock vanagon is p/n 251-959-481K 85,93, but many put in the low temp switch 251-959-481-75 in instead. Especially those with conversions.
  • New temp sensor p/n 049-919-501
  • New radiator hoses p/n 251-121-083H & 251-121-082
  • New SS Coolant Pipes if you can get them!

The 82 & 83' diesels have a radiator setup that should be overhauled to the newer setup.

The main differences between this setup compared to the later vanagon radiator setup is the following:

  • Newer radiator shroud (metal) non-ac from an 85-90 van to be safe. The stock diesel one is plastic and not usable
  • Newer 85+ radiator mounts

You can use an AC fan-shroud, but you'll need to make an adaptor as shown below.

  • Newer lower radiator support brackets 85-90. It doesn't matter if it's AC or non-AC
  • New radiator hoses; the return hose is different between the diesel vanagon and the newer setups

Obtaining Hoses

So, you may be trying to locate an alternative to the DV crazy hose setup.

You can get new silicone made hoses by GeeBee


These were the references I used to get the job done on my van and help another with theirs.

Radiator and Cooling Upgrade

Radiator Install

Electrical Setup

Rad Fan Replacement

Radiator Replacement


This was pretty easy. Once you put the new style brackets (they are a C shape almost) and use the same 13mm hardware as your existing.

The only thing you need to fabricate, is the top bracket to hold the radiator in. This can be done by a simple L bracket for a drawer or something. It'll be aparent when you look. Like this:

83radiator upper bracket.jpg

Here is a photo of what the "newer" 83+ style brackets look-like


Radiator Fan replacement

p/n 165 959 455AM

You will need to use an 85+ radiator shroud (metal) for a non-AC Vanagon.

However, if you can only find an AC based shroud, you can still use it.

You just need to make an adaptor plate for the non-AC fan to fit the AC shroud.

This can be done tracing the File:Diesel-acshroud-template.pdf template. I originally used a bucket lid when I discovered this issue; stoned engineering tricks!


Original bucket-lid! This made me 2000 miles from STL to LA and then some.


Template marked on sheet-metal; if using thin sheet-metal double up!



Metal sheet-metal version; NOTE: you should test spin the blades to make sure it clears. It SHOULD, but better to test before giving live power!


My original bucket-lid version installed ;)

Radiator fan replacement.jpg

Radiator Fan Electrical

Old Radiator Electrical Setup

Old rad electrical.jpg

So, with the new setup, you'll have only one switch and three wires.

The four wires you see in the photo should be:

two heavy wires - low fan setting

two thin wires - high fan setting trigged from the relay

You'll connect female quick disconnects and connect to the temp switch via a pig-tail.

For this pigtail, I recommend 10g wire with the colors Red, Black, White.

You will need a multimeter or something to determine which wire is hot

Of the two thin wires the one which is LIVE (HOT) is not used anymore. This can be trimmed, cleaned up, bent back, and taped up to not be used anymore.

This leaves you with THREE wires:

2 heavy wires
1 thin wire

Now, at this point you want to see which of the two LARGE wires is LIVE (HOT)

Now, you need to build your pig-tail

Heavy wire with constant +12 goes to pin labeled + on the temp switch (towards the bevels on the end) - RED
Heavy wire to fan low speed connection goes to pin 1 (center of temp switch) - BLACK
Light wire to fan high speed relay control goes to pin 2 (furthest away from bevel end) - WHITE

This can be seen in the photo below:


This is how the pig-tail was done when installed

Radiator electrical update.jpg

Okay, at this point we'll want to hook up the actual radiator fan.

Cut off the old connector for the rad-fan off the current wiring harness. At this point you'll want to put female quick disconnects on the wires:

The new fan pin-out is:


Now your old plug had three wires:




Place female quick disconnects on those and plug into the new fan!

Radiator Fan Electrical Testing

At this point you want to test your circuit for the LOW & HIGH fan.

Disconnect the three wires from your radiator temp-switch that you installed earlier with the new pig-tail.

Get a short piece of wire to jump across wires for testing.

If you short the R & B you'll get LOW

If you short the R & W you'll get HIGH

If that works then your circuit is good! Just hook up the wires back to the temp switch!

Libby Bong

1x 2"x30" black pipe(pre cut piece sold at homedepot)

1x 2" to 1 1/2" rubber reducer with clamps

1x 5/16" brass hose barb

10ft of 5/16" silicone hose, couldn't get any smaller quanity.

cost me $15 bucks to make it, plus it looks cool sitting in my garage.

Diesel adaption


Coolant Level Sensor Upgrade

Most 82' & 83' diesel vanagons had no coolant level sensor like the later years. This diagram helps implement it;


VW Oil Coolers



Choose an Oil Cooler:

1x 028117021E - oil cooler V6 4Motion Cooler - Good for Stock AHU engines
  • 1x 028117070B - oem cooler seal. The febi one sucked
1x 038117021B - oil cooler for a 2.0 TDI engine - Good for Enhanced AHU Engines
  • 1x 038117070B - oem cooler seal.

Get the tube & nut; same for both O/Cs

1x 028115721B - union tube
1x 068115723 - hexagon nut; ADC,AAZ,ABA,; AHU,1Z


This is pretty simple just slide it over the (028115721B - union tube) into the oil-filter assembly. The ports will face left of the engine indicated in the photo below. If you look at the top of the cooler and inside the flange you'll see the 'oil' feed line hole. Those basically need to match up.

Then place the oil-cooler over it and attach with the (068115723 - hexagon nut)


This is what a 2.0 TDI O/C with Karl's moddification done installed looks like:

PD130TDI OC.jpg

Aux Oil-Cooler Modification

The default DV aux oil-cooler doesn't allow for constant flow of coolant. Only when the thermostat opens.

This is kinda silly since all the newer diesels implemented a better setup.

Therefore, this SHOULD be REQUIRED for all DV owners.


TheSamba - Karl M. @ WestyVentures
TheSamba - OutWesty restated the above


Seeing is believing like they say. It also helps visualize what has to happen. This was indeed the case with me!

Karl M. @ Westy Ventures drew this up to explain what's required for the modification that he explains in TheSamba post.

Karl M-WestyVentures-DV OilCooler modification.jpg

For the Tee you can search ebay for sometrhing along: Coolant Hose T Fitting Radiator Hose T Fitting Hose Splice 1" X 1" X 5/8" VW has one under p/n N90693001. Also Kat’s steel 5/8x1 tee at most FLAPS p/n 28113

Which should look like this:

DV aux oil mod Tee.jpg

If you prefer a Y based solution, go to Heater Craft

For attaching the hoses make sure to use rolled-edge SS clamps, as they don't cut into the hose as traditional hose-clamps do.

Fot the 1/4” restrictor you can use a fender washer with a 1/4" hole and a 1.25" OD


NOTE: The 1/4” restrictor with RMW “The Tank” caused too much pressure and pissed out cap. I removed restrictor no coolant loss out of cap. Temps still low. YMMV

Heater Hoses

While doing the coolant pipes/hoses, you should also replace your heater hoses. Mine were so soft/brittle that my thumb nail could puncture it!

I had no rear heater or fun accessories, it was just a 5/8th heater hose about 27ft get 30ft to be safe. Also, get a proper 1" to 5/8" reducer for your cylinder head flange.

This hose reducer is for the end of the cylinder head where the 5/8" hose goes into a 1" barb. Many will "squeeze" the 5/8" onto the 1" which is a BAD idea. You're likely to split the hose at some point. I actually helped a couple in their conversion in a diesel vanagon with this exact problem. Get the reducer!

Now, in the photo below, the one with the tape band goes to the cylinder head. The one with the stock control valve goes to the coolant tank hose.

DV heater hoses.jpg

Note, that I also have a valve on the right side, a mod from BlueHighway Vanagon.

With the valve installed, the flow of hot water to the heater core can be completely shut off, allowing cool, fresh air to be circulated through the system.


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