Jetta TDI Intake Decoking (ALH Engine)

Generally we love Volkswagen’s TDI engines.  They produce great power, are much easier to live with than the older Turbo diesels that VW made, and have amazing fuel economy.  They really only have two weaknesses:  they HAVE to have their timing belts serviced on time.  AND they like to coke-up in their intake manifolds thanks to the EGR (Exhaust Gas Recirculation) system.  Here’s some before and after pictures of the decoking we did on a 2000 VW Jetta TDI with the ALH TDI engine.  The car has approx 130,000 miles on it.  The power difference from before we did this service to afterwards was amazing.  Here’s the pictures:


TDI Intake Manifold Plugged


TDI EGR Valve Plugged


TDI Intake Manifold Cleaned


TDI Intake Manifold Cleaned (at cylinder head)


TDI EGR Valve Cleaned


If your TDI is feeling like it  lacks power  – particularly at high RPMs it may be time for you to do this service too.  EVERY TDI needs this sooner or later.


Chevrolet Aveo / Daewoo Timing Belt

Here is a deceptively simple timing belt job.  This engine, built by Daewoo, is found in the 2002-present Chevrolet Aveo.  The timing belt has a notorious reputation of failing early and we strongly recommend you replace yours before you get to 50,000 miles.  This engine design is an interference engine which means that if the belt breaks or slips it will cause (expensive) internal engine damage.

Generally this is a simple procedure:  disassemble the front of the engine, remove the engine mount, and roll the engine to get to Top-dead-center on cylinder #1 on the compression stroke.  The cam pullies have marks that will point towards each other when in the correct position – see picture:

Chevrolet Aveo Timing Belt Installed

Also note the marks on the timing belt – it is our shop’s practice to mark old timing belts before removal and then to transfer these marks to the new belt.  They serve as a back-up system for ensuring that the new belt is on correctly.  (NOTE:  You have to be very careful to be sure the marks are copied correctly from old belt to new / count belt teeth twice!)

The belt tensioning is the tricky part of this service.  The waterpump (the toothed pulley with the special tool on it in the pict above) is used to load and unload the tensioner.

The pulley above the waterpump and below the intake camshaft is the actual spring loaded tensioner – see picture below:

Aveo Timing Belt Tensioner

To properly tension the belt (with engine in top-dead-center #1) loosen the waterpump and turn it (using special tool) until the tensioner pointer is pointing to position 1 in above picture – then tighten down the waterpump.  Next roll the engine through two full rotations to get back to top-dead-center #1, loosen the waterpump and reduce the timing belt tension until the tensioner’s pointer is pointing to Position 2 in the above picture.  Re-tighten the waterpump and roll the engine a few times and verify that all of your timing still lines up.  If so ensure everything it torqued down properly, reassemble the engine, and enjoy it for another 50,000 miles!

The special tool – shown below – is almost necessary for this procedure:

Aveo Timing Belt Tool

You *can* get away with using a 41mm crow’s foot and a short extension but it’s tricky.  The important thing is to be sure the belt is tensioned properly before starting the engine.  Remember:  if the the belt is too loose it can skip and cause internal engine damage.

We bought our tool here:

Sealey VS090 Daewoo Water Pump/Timing Belt Tool

Please email if you have any questions!


Freelander Timing Belts

Here’s a fun one:  a Land Rover Freelander’s timing belts.  This engine is a 2.5L double-overhead cam with three (count them:  three) timing belts.  Moreover these should be serviced every 60,000 miles or so.  Since this engine is an interference design if a timing belt breaks or slips you will have internal (expensive) engine damage.

Although this is probably a service that can be done without special tools we don’t recommend it.  The key to getting the job right, as with any timing belt service, is to mark everything.  If you mark the old belt, transfer the marks to the new belt, and get the new belt on exactly where the old one was you’ve obviously got the new belt on correctly.  It is easy to get off by a tooth though so count twice and install the belt once.  Any timing belt job done this way can get scary and if you find you cannot get things back where they belong you then have to have the correct tools to align the engine.

Timing Tool Kit:

Freelander Timing Belt Tool Kit

Starting Point – air filter housing removed.

Freelander Timing Belt Starting Point

Serpentine Belt:

Freelander Serpentine Belt Removal

Note that you cannot fully remove the serpentine belt without removing the ‘front’ engine mount seen here below the alternator.  What this means is, if your serpentine belt is even slightly worn you’re smart to replace it while doing the timing belt since the labor completely overlaps.


Next Step:  Remove Upper Intake

Freelander Intake Removed

Note that when removing the upper intake it can feel like it has gotten stuck and you’ll go hunting for hidden bolts underneathe the back side or something.  Most likely it is just stuck on the large green o-rings you see in this picture.  Also note the shop-rags inserted into the intake runners.  We do this to protect the engine from something falling down into the intake.  Even a small bolt dropped in the wrong place here could ruin the engine.

Freelander Upper Intake O-Rings

Next step is to be sure our engine is in the ‘safe’ position:

Freelander Crankshaft Safe Position

The camera angle makes it look like these marks are mis-aligned but when viewed from directly in front of the harmonic balancer the marks line up perfectly.

To keep the crankshaft in the safe position you use your first tool from the tool kit to lock the crank:

Freelander Flywheel Lock Tool

Not easy to see here and not easy to install but here is the tool – once this is installed the engine is locked.  You’re probably wise to disconnect the negative battery terminal at this point since someone hitting the starter motor at this point could be very bad!

Here’s the flywheel tool from futher back:

Freelander Flywheel Lock Tool Installed

Here’s the front belt coming off / notice we still mark belts at our shop even when we have the alignment tools.

Right Side Cylinder Head:

Freelander Right Side Front Camshaft

And the left side:

Freelander Left Side Front Camshaft

To replace the front belt you need to remove hydraulic tensioner assembly and lock it.  The tool kit comes with a pin for this but really any pin would work.  Before remove the tensioner we recommend you remove the idler pulley on the left side of the engine – this will slacken the tension on the tensioner and make it easier to remove.  Land Rover recommends that if the tensioner bolts are too tight you should soak them in some type of penitrating oil.  If this does happen it is also recommended that you replace the bolts.

Next you can pull the old belt off, partially install the new belt, and then align it.  Before installing the new belt be sure to inspect the tensioner and idler pulley and replace them if they are even slightly questionable.  Also check the hydraulic tensioner for any signs of leakage – again play it safe and replace it if it’s even slightly questionable.

Putting the front belt back on we use the upper alignment tool to ensure everything is aligned correctly:

Freelander Front Cam Lock Tool

The tool kit comes with two of these tools so that you can lock both front cams at once.

Once the front belt is back on and you’re satisfied that it is aligned correctly it is now time to tackle the rear belts.

Freelander Rear Timing Belt

Above is the front cylinder bank’s rear timing belt.  Notice that it doesn’t have any tensioner assembly.  To replace it first mark both cam pulleys and the belt then remove both pulleys and the belt as an assembly.

The rear cylinder bank is a little harder to deal with but take your time and be sure you have your timing belt marked:

Freelander Rear Cam Timing Belt

Here’s the front bank with the alignment tool installed and the intake cam mark showing:

Freelander Rear Cam Timing Lock Tool Installed

Here’s the new belt installed on the pullies before installing back on the engine:

Freelander Rear Timing Belt Installation

The tool kit comes with nice ‘pegs’ that you put into the cam bolt holes.  You can then slide the cams in place using the ‘pegs’ as guides.  BUT – here’s one of the trickiest parts of the whole process:  the EXHAUST CAM WILL HAVE MOVED and you’ll have to roll it back to get the cam pulley back on.  With the tool kit there is a bolt on the front lock tool that allows you to turn the exhaust cam with a wrench – without this we recommend using a chain wrench over the large smoother outer section of the exhaust cam to allow you leverage to roll it back.  BE VERY CAREFUL!

The rest, as they say, is simply the reverse of removal.

Once all belts are on remove the flywheel lock and roll the engine a few times then recheck all alignment marks to be sure everything is aligned.  Then reassemble the engine.  Once starting the engine if you get any abnormal noises shut it down immediately and recheck everything.  If you get a check-engine light on recheck your timing and read the computer error codes to see what it is complaining about.

Like every timing belt job it just takes cautious work and double/triple checking everything.



Misfiring VW AWM Engine

This was a fun one.  A 2002 VW Passat with 1.8T AWM engine.  The car came in with misfire / most noticable at idle.  Smoothed out ok when the throttle was opened up.  We tested all the basics:  checked the diagnostic error codes, smoke-tested the intake for vacuum leaks, data-streamed the mass-airflow sensor signal, etc, etc.  The basics of the engine all appeared good but the engine ran pretty poorly at idle and it kept throwing error codes.  Interestingly one of the error codes it threw more consistently was a camshaft-crankshaft correlation error (sorry, I can’t remember the specific code number).  Naturally we checked the valve timing by checking the timing belt – everything lined up.

So we decided, since we had a spare (known good) camshaft sensor on hand that we’d try to swap it and see if the sensor was producing a poor signal.  That didn’t help.  We inspected the crankshaft sensor too – it appeared to have been replaced once but there was nothing about it that made us think it needed replacement.

The engine had a leaky valve cover gasket and the oil was contaminating the spark plug boots so we decided, as a smart next step, to sell the customer a new valve cover gasket with the bonus of allowing us to inspect the camshafts, etc while the valve cover was off.  Here’s what we found…


VW AWM Exhaust Camshaft Timing

Check the red-circle in the picture – the exhaust camshaft timing was dead-on.

Notice also the cam lobes, etc all look decent.

Now – check out the Intake Camshaft:

VW AWM Intake Camshaft Timing

WOW – look that – the intake timing is off by one tooth!

Even closer inspect revealed this:

VW AWM Timing Chain Tensioner Damage

Notice that chunk of material in the red circle?  It’s part of the timing chain’s tensioner’s lower guide.  Evidently the tensioner had a problem with the lower and the intake camshaft jumped one tooth.  So why didn’t we see this when we checked the timing belt?  Well, the timing belt aligns the exhaust camshaft with the crank – not the intake camshaft.  This was the timing tensioner can vary the intake valve timing by increasing and decreasing the tensioner on the chain between the two camshafts.  We replaced the the tensioner assemby and the timing chain, reset the valve timing, and retested the engine:  fixed!

Service Lane with Lifts and busy professional technicians

Brake Hose Damage

Here’s something we see too frequently:  brake hoses that are cracking.  These were on an Audi, which, for some strange reason, seems to have this issue more frequently.  The fix, obviously, is to replace the lines.  This is a potentially life-threatening problem so don’t take a chances on this one:


Right Front Brake Hose.



Left Front Brake Hose



Misfiring Vanagon

This one was a challenge.  Older European vehicles (1980s or so) can be particularly difficult to diagnose because they use a lot of modern technologies like fuel injection but they don’t have any computer diagnostic data so testing them requires testing components individually.  This was very true of this 1983 VW Vanagon.  It has a 2.0L flat-four engine with fuel injection and distributor ignition.  It was running very rough and lacked significant power.  (Something a Vanagon can’t afford to be lacking in!)  There had been other attempts to repair it including replacement of the airflow meter.  We started our diagnostics (after a test drive) by using an ignition scope – here’s what we found:

Vanagon Ignition Scope

Notice something wrong?  Cylinder #4 (third graph from the top) has no ignition trace at all – none!  That was a surprise.  We swapped ignition wires and used a spark tester to verify what the scope showed us:  no spark going to cylinder #4.

So, next we popped the distributor cap and rotor off to physically inspect the distributor.  This van had an aftermarket distributor made by EMPI which eliminated the need to use ignition points (yay!).  Here’s what we found inside:

Vanagon Distributor

Notice in the top middle?  One of the magnets is missing!  We found the magnet inside the distributor housing, glued it back in and voila!  The Vanagon was suddenly running on all four cylinders.  After other basic engine adjustments the van’s power was back.

Aircooled Volkswagen Vanagon

Expedition Heater Core

Heater core failures are always fun.  This Ford Expedition was leaking coolant on the ground in large quantities.  The fix was a new heater core.  It always impresses me to see how much of the car needs to come apart for this type of repair.  Here’s some pictures:

Expedition Dash Removed Passenger Side


Expedition Dash Removed Driver's Side

Here’s the heater box and the leaking heater core:

Expedition Heater Core

Heater Core Leaking


Beetle Narrowed Beam

To go along with this 1974 Beetle’s new engine the owner wanted a more raked look.  We narrowed the front suspension beam by 4″ and adjusted the torsion bars down.  Here’s the results:

Lowered Beetle

Slammed Beetle

Beetle Engine

Here was a fun one – we swapped out the 1600cc engine from a 1974 VW Beetle and put in a built-up 2100cc.  Should make just over 100 horsepower.  Not bad for a Beetle!

Take a look:

Beetle 2100cc Engine

New Venture Transmission

A good customer brought us their work-truck with its transmission stuck in 5th gear.

We didn’t find any dirty gear lube or metal chunks in the transmission gear lube.  So we took a chance and tore this gearbox down instead of sourcing the truck a new transmission.  We got lucky, all it needed was a new 5th gear shift fork.  Here’s some pictures:


Broken Fork:

New Venture Transmission broken shift fork


Closer view:

New Venture Transmission broken shift fork closer


Here’s the new fork installed:

New Venture new shift fork