Jetta TDI: Head Gasket Replacement
The timing belt was removed. Note the drill bit used to lock the injection pump into place.
In advance: I apologize for the blurry photos! I need to replace my wife's camera, so that I get my good one back. I took these with my phone, and the quality is horrible!
In my commutes to and from Columbus from my home near Martinsville, Indiana, my 2001 Jetta TDI has been getting 47 mpg with 266,000+ miles showing on the odometer. However, it started using coolant, and this needed to be addressed.
My own investigations found that the coolant wasn't leaking onto my garage floor, so the usual suspects, including a bad water pump seal or a leaky hose, were immediately dismissed. The coolant level might be OK for a week or so under normal driving conditions, but if I drove at elevated highway speeds or in a spirited fashion I would quickly get the low coolant alarm and need to top off the spherical tank under the hood. I found that the coolant system was being pressurized under high boost conditions, creating gas bubbles and even pushing the coolant out of the water bottle.
A search around the excellent forums at TDI Club showed me that this was a known issue that occurs to the 1.9 liter ALH TDI engines. It's caused by a leaky head gasket.
The situation wasn't too severe, yet, so I thought I'd try to increase the clamping force on the head. The stock head bolts are of the stretch type that cannot be reused. They also limit how much clamping force can be asserted. I knew that ARP makes a stud kit for these heads, so I thought I'd give it a try. I found out that DaveLinger on TDI Club had the same problem and was able to fix it by upgrading to the ARP studs. I ordered them, did the upgrade, and found that it didn't fix my problem.
So, I bit the bullet and ordered up about $400 worth of components from Kerma TDI. I found that they had the best bottom-line total price, even though I still needed to pay some $21 in shipping. Others had "free" shipping, but their total price was still higher. I'm running a mild Kerma tune in my car, and know that Kerma specializes in TDIs and knows their business well. I ordered a head gasket kit, a couple bottles of compatible coolant, a timing belt kit, and a replacement expansion tank (the old one was looking rough). The timing belt kit was added because I already had 66,000 miles on the current belt and if I was removing the head, I might as well replace the belt early and be good for another 100,000 miles. The kits were pretty deluxe and included stretch bolts, gaskets, seals, rollers, and other stuff that one isn't likely to think of when doing this job. It was about $400 in parts, but I know that this job would cost $1200+ for somebody else to do it.
When the parts came, I thought I could get this done in a weekend. I work slowly, though, and it took two weekends to get everything back together and a third to get everything running correctly.
I locked the camshaft into position by removing the end bearing cap and using this piece of angle aluminum shimmed with some sheet metal.
I started by pulling out my Bentley Volkswagon Jetta, Golf, GTI 1999 to 2005 Service Manual and slowly worked my way through removing the timing belt process prior to switching to the head removal process. I should point out a couple cheapskate things I used for tools during this process. The Bentley manual calls out some special VW tools, but there are workarounds. Much of this came from checking out GallowayChicago's YouTube video on the subject. One is using a 15/64" drill bit to lock the injection pump in place. He also recommended removing the bearing cap on the end of the cam and using a saw blade to lock it into place using the groove built into it. I took his advice, except that I used a piece of angle aluminum shimmed with some sheet metal I had laying around. Further, rather than using some other fancy pin spanners on the tensioner, I found that the Park Tool SPA-1 had the right pin diameters when I found it on Amazon, so I tried it out and was pleased that it was exactly the right tool for the job. It was only $10.
This simple, homemade tool was used to counter torques when loosening the camshaft sprocket.
To counter torque when loosening the camshaft sprocket, it is very important that you don't use your locking mechanism or you will likely twist the camshaft. So, I simply used two pieces of angle iron with a bolt acting as a hinge and two other bolts at the end used to contact the sprocket and keep it from rotating. It gives me plenty of leverage!
The Park Tool SPA-1, a pin spanner made by a company that specializes in bicycle tools, works perfectly for setting the tensioner on this engine.
When I was removing the head, I found that I'd forgotten to disconnect the oil line to the turbo. This steel line was quickly messed up in the procedure and it looked like a real mess to reinstall an new one. Bora Parts had the answer for me, that was about the same price as the best deal I could find for the OEM line: a braided stainless turbo line. It was easy to route and install when everything was being reassembled.
When the head was removed, I cleaned up all of the surfaces with a gasket removing chemical and a plastic scraper. I wouldn't use metal to remove gaskets from an aluminum head, as you will certainly gouge the surface and screw up the ability to seal with the new head gasket!
I used the Permatex gasket removing chemical that is applied with a brush to remove remaining gasket materials from the head and the engine block.
When I reassembled everything on the second weekend, I found that I couldn't start the engine. With my crazy work schedule, I had to hang it up until the next weekend.
I began looking through everything to see what I did wrong. I found that my timing was off one tooth, which is apparently a common error that will happen when tension is applied to the belt. However, correcting this still didn't allow me to start the engine.
I had used a Mityvac to prime the injection pump before trying to start the engine, but it didn't seem like it was getting any fuel. I did a cold compression check, and knew I had good compression, so simple logic dictated that I wasn't getting fuel into the chamber.
I searched through forums for "no start" conditions checked a number of things, including electrical connections going to the injection pump. Everything looked OK. Finally I stumbled across one person who mentioned priming the injectors and tubing that had been disconnected in the process. I cracked them open, cranked the engine, and tightened them back down. Now the engine started with no issues. There must have been a bunch of air in those lines!
Injection pump timing is adjusted by removing the upper timing belt cover and loosening the three bolts that are in slots on its sprocket. Then, the central bolt is rotated to adjust the timing and the bolts are retightened.
With the engine running, I pulled out my Ross-Tech VAG-Com and took measurements on the actual injection timing. This tool allows me to look at, record, and adjust a large number of features and variables on my car. There is an acceptable timing range for the injection event, and this tool gave me a graphical indication of where the event was taking place.
At first the injection was too far advanced, with the events being recorded above the visible range on the graph. On my first tweak I moved it just below the acceptable range. After a couple more small adjustments, I got the injection events timed on the advanced side of the acceptable range, but still within it. This is a safe timing setup that will provide the best fuel economy.
The VAG-Com allowed me to mechanically adjust my timing until it was ideal. Advanced, but within the acceptable range.
I learned a lot of lessons in this process, and if I need to replace a belt or pull a head from one of these cars again, in the future, I'll be able to do it much more quickly and easily. In addition to the knowledge, I also have more of the tools for the job.
-Putting the "engine" back in "engineering!"