[T3] Removing Oil Pump - In car

[Jim Adney]

On 2 Apr 2026 at 17:52, EL PUERCO wrote:

> So, I'm dealing with a low oil pressure issue and have narrowed it down to
> the pump.  I must have used the wrong gasket or maybe a pump gear is
> loose.  Is it possible to do this in-car rather than pull the engine?  I'm
> thinking yes but I'm really not looking forward to it.

Yes, it's possible, and it's even easier, since there are so many things you 
don't have to deal with to take the engine out. We've had to do this several 
times on Caravans to Invasions, to fix fan housing screws that had worked 
their way out. With the right tools and plenty of help, it can be done in a 
couple hours.

Before you start down this road, check other problems. Check the pressure 
relief valves to make sure they are free. Check that there's not a problem 
with gas getting in the oil and thinning it out. Keep in mind that oil pressure 
in our VWs is nothing like that in a Ford or GM. It's measured in a different 
place and is normal to be "low." (How low is yours?)

Our engines do not need a lot of pressure to insure good lubrication; they 
just need enough to keep the bearings full. If the spaces between the crank 
and the bearings are full of oil, the rotation of the crank will drag the oil into 
the places where it is needed, producing high oil pressure THERE, not 
applied from outside.

This is the hydrodynamic process that makes journal bearings so effective. 
They don't need lots of outside help.

Gene Berg used to say that our engines didn't need pressure, they need 
FLOW. They don't need lost of flow; they just need enough, and I'll admit 
that it's really hard to tell when they're getting enough. It's important to 
understand that if you go to a bigger pump, you're just wasting engine power 
to pump more oil than necessary. Flow x pressure = power used in the pump 
and removed from the drive train. I'm not a fan of 30 mm pump gears. VWs 
eventually went to 26mm for use with the late dished cams, but the 
aftermarket 25 mm pumps that are compatable with the early flat cams seem 
to work just fine.

Here's how to remove the fan housing:.

Remove the generator.

Free up the air ducts that connect to the fan housing outlets on each side.

Free the engine end of the cooling air intake bellows and fold the bellows 
back into the body.

Remove the cap on the pulley and unscrew the pulley/fan bolt. You will 
probably have to lock the crank somehow, in order to apply enough torque to 
free that large bolt. Lock the crank by turning the engine until the distributor 
rotor is pointing to the #1 position. This puts #2 at BDC, just past its 
compression stroke. Remove the #2 spark plug and sfuff as much rope down 
that hole as you can. Then when you torque that bolt CCW, the piston will 
move backwards up to TDC on the #2 compression stroke. You always want 
to compress the rope against CLOSED valves, so you don't bend them. 
(You'll need to back up and restuff the rope before retorquing CW, starting at 
TDC for #3.) [The rope trick is the only extra thing you'll have to do with the 
engine IN the car. With the engine out, there are easier ways to lock the 
crank.]

Remove all the small bolts that secure the pulley cover, and remove the 
pulley and pulley cover together.

Remove the M8 bolt that secures the black "handle" to the upper right side 
of the fan housing. Remove the handle and bolt together.

Remove all the small bolts that hold the fan housing together. Some of the 
ones on the bottom will be hard to reach, but they can be done.

The fan housing has two dowels that align the two halves, one on each side 
just below the outlets. They are in the later blocks of alum (or magnesium) 
cast under there. They are likely to be tight. You can free them by using a 
narrow metal chisel tapped into the parting line of those larger blocks. Do 
not try to pry elsewhere; that is likely to break the fan housing. Remove the 
rear half of the fan housing.

Remove the fan. It is likely to be hard to get off. DO NOT PRY the outside 
edge. It will bend. Gentle wiggling from two hands on opposite sides will 
often do it, but you may need a steering wheel puller and two long M8 bolts 
to pull it out. It's not a press fit; it's just tight from being there a long time.

This part can be hard. You need to disconnect the thermostat linkage from 
the flaps in the front fan housing. It may help to unscrew the bolt from the 
bottom of the thermostat, to allow the thermostat to rise up and allow access 
to the underside of the flap.Unhook the spring at the flap end, being careful 
to leave the forward end attached as is.

The rod part of the linkage can be released from either end. If you can do it 
from the rear, easily accessible, end, that may be easier, but there are little 
washers and locking pieces to keep track of and not break. Releasing the 
front end require access to a locking bolt after removing the spark plug 
access cover over the #1 & 2 spark plugs. If you loosen (dont remove) that 
bolt, the rod will slide out easily but it will be hard to reinstall and will require 
re-adjustment on re-assembly.

Loosen the 4 small bolts that hold the cooling tin around the fan housing exit  
ports.

Remove the 3 or 4 small bolts that hold the front half of the fan housing to 
the case and breather stand.

Remove the front fan housing.

Now you have complete access to the pump.

Remove the 4 special pump nuts, with the red plastic seals. The special nuts 
& seals can be reused if you are careful. If there are just plain hex nuts 
there, those may be the cause of your leak. Get new sealing nuts, if 
necessary. Do not use any washers under those nuts.

Take the pump cover off, check the driven gear to make sure it hasn't been 
spinning on its shaft. Inspect the drive lug to make sure that its evenly worn 
on both sides Then install it with the drive lug NOT engaged; then turn it until 
the lug drops in. Make sure it drops in far enough to insure a secure 
engagement, but not so far that it bottoms out.

If you decide to remove the pump, you'll need a special VW pump puller. it 
helps to loosen a couple nuts on the long sideways studs above and below 
the pump, but you'll still need the puller.

Do what you want to do, then put things back together in reverse order. 
You'll probably need a new, thin pump cover gasket, and a new thick pump 
gasket under the pump, if you removed the pump.

If you have time and are willing to do an extra good job, and are not 
interested in doing this job again, consider installing M6 x 1 Helicoils in the 
two threaded holes in the case, on either side of the crank. The original 
threads there often corrode to the point where they no longer hold those 
small bolts in place. Then those bolts walk out and rub against the fan. This 
makes a racket and eventually destroys the fan.

You can drill the left hole any depth, it will just break thru OUTSIDE the 
case, but the right side hole will break thru INSIDE the case, creating a small 
leak. I don't remember how much extra depth is available there, but it's not 
much, maybe 1/4". So don't drill much deeper than the original.

I use long, locking Helicoils, recessed slightly into the case, to get into 
strong case material, with the longest M6 x 1 bolts that will fit. I probably 
start with 30 mm bolts and cut them down so they just fit. When you're sizing 
them, don't forget to allow extra length for the thickness of the fan housing 
and a washer under the bolt head. If you're finished and putting everything 
together, only to discover that your bolts are slightly too long, just add 
another washer or two under the bolt head. I usually install those bolts with 
locktite in addition to the locking Helicoils.

When the front fan housing is out, I recommend sawing a small slot in the 
right end of the cooling flaps shaft. Saw this slot parallel to the flaps and you 
can use it to check where the shutters are (open, closed, etc.) and you can 
also insert a screwdriver in that slot to check that the shaft is not seized.

Sorry, this was long; it's complicated, but most steps are easy. The hardest 
part is likely to be dealing with the cooling flaps linkage.

Good luck, and let us know how it goes and what you find.

And, BTW, I lived in Carlsbad, just a few miles south of you, for 9 months in 
the early 70s.

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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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