[T3] Removing Oil Pump - In car

[Max Welton]

My approach to immobilizing the crank with the engine in the car is to
put the transmission in 4th gear and pull the parking brake on. I
don't think there's a danger of breaking something in the transmission
with 90 ft/lbs to the bolt but I could be wrong. But it has worked for
me.

Max

On Fri, Apr 3, 2026 at 12:49 PM Jim Adney <jadney at vwtype3.org> wrote:
>
> 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.
>
> --
> *******************************
> Jim Adney, jadney at vwtype3.org
> Madison, Wisconsin, USA
> *******************************
>
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