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Ressurecting a 98 Jetta TDI that has been not been started in years

This is one of my childhood cars that I’ve had in the garage for probably about 3 years and have sadly neglected. It hasn’t been started up in at least 2 years. I’d like to turn this into a project car one day (maybe a grease-mobile) or something fun. I’m no exactly mechanically inclined, but I can read a Chiltons manual. What should I expect to have to do to get this car working? Currently what I know is that it has a dead battery, but I don’t want to try to just replace the battery and fire it up. There is some diesel currently in the tank.

Charge the battery and see if it can take and hold a charge. If not, get a new battery. You should plan on changing the oil, coolant, transmission, and brake fluids but I don’t see why you can see if it fires up and runs with a charged or new battery? If you get it running things like new fluids and new filters should be taken care of before you put it on the road and start driving it. Old belts, old hoses, old tires, and old brake lines should all be either inspected and/or replaced if you want a reliable car for any long trips.

Sitting for 2 years isn’t that hard on the engine, if it was in decent shape before it was last running. There is a real likelihood you will have brake problems. Frozen and/or sticking brake calipers are common due to rust and corrosion.


I highly recommend you do NOT convert the car to run on waste vegetable oil

Many of the people that have done this have severely regretted it later, because injectors, lines, hoses, etc. were leaking or plugged up soon afterward

A new battery, 5 gallons of fresh fuel, check the fluids, crank it up…How many miles on it?

Caddyman, It has 150K miles and was still running strong. No engine issues however I did get the timing chain replaced at 100K.

If it has been sitting for 2 years a new battery is a good start especially with a diesel due to the higher compression. If draining the fuel is not an option at least add some diesel fuel conditioner. Vehicles sitting are usually forgiving if they were running before. Make sure your coolant level is good as well as oil level. If it has a block heater I would plug it in for a few hours before attempting to start. Hit the key and give it a go. Don’t crank it for longer than 10 to 15 seconds at a time, the starter can overheat if cranked continuously. After it fires up let it come to operating temperature see if it will move forward and backward a few feet and then shut it down. Now change your fluids, oil, coolant, trans fluid and brake fluid. Pull the wheels and check the brake hoses and pads / shoes as well as calipers and wheel cylinders for leakage or sticking. As far as the cooking oil conversion I have seen some work very well and some not. Depends on if it is done right. Diesels were originally made to run on vegetable oil. Enjoy.


“Diesels were originally made to run on vegetable oil”

I believe you’re referring to the very first diesel motors from the 19th century, not from the 21st century

No offense intended

I believe the Model T was also capable of operating on some alternative fuels. I forget what they were, though. That does not mean it’s advisable to operate a modern non flexible fuel gasoline engine on something other than gasoline. At least not without some major modifications

Thanks everyone!

Aired up the tires and tossed in a new battery, 5 gal of fresh diesel and a bottle of conditioner. The first 3 attempts to start failed. I let it sit for 3 minutes and tried again. Eureka! Checked all the fluids, brake lines, brake calipers, and surprisingly everything looked fine. Took it for a short and safe stroll down the street with no problems. Parked it overnight with some cardboard underneath and there was nary a drop of anything staining it in the morning.

I did notice that she is more sluggish than I remember. I wouldn’t doubt if there are some heavy carbon deposits in the exhaust manifold and EGR valve. Should that be the case, what’s the recommended course of action to clean it? Remove and chisel out the buildup, chemical solvent like BG, fire cleaning? I have my Chilton’s manual and am not afraid to use it!

First change the oil, oil filter, and fuel filter(s). I’d also change all other fluids and filters. How old are the tires?

Other than agreeing with changing all of the fluids and filters I might pose this.
You state that the car is “more sluggish than I remember”. What have you been driving up to this point?

Maybe this sluggishness is more perception than anything else due to driving a snappier gasoline rig around prior to this diesel.

There’s also a possibility that sitting has gummed up the turbocharger impeller and that it’s not spinning as freely as it should be.

It seems to me that this is a pretty sluggish car anyway, and I agree with @ok4450 that it might be OK. My experience with waking up sleeping vehicles (mostly motorcycles, but it’s similar) is that the first 100 miles is the key. At first everything feels wrong, and you are just waiting for things to happen. Then you start to believe that it might be OK, and things have a way of sorting themselves out. Take it easy for a bit, and let everything go through a couple of heat and cool cycles.

And make sure the tires aren’t dried out or cracked or hardened or just in bad shape. Tires don’t age real well, and sometimes look OK but are hard as a rock and skid on everything.

So, what is a “brake pan”? Also, why would anything carbon up just sitting there? You said it ran strong when stored.

If you can find a shop who will drain all the old fuel out of the fuel tank, I’d put that as a priority. After it is out, sieve it through a fine sieve and see how much debris was in the fuel. If there’s a lot of gunk in the fuel, I’d be inclined to ask the shop to remove and clean out the tank. Also a good time to do the experiment to check for any water in the fuel.

The reason for this is that if gunk gets into the fuel injection pump, or clogs the injectors, you are looking at a sizeable shop fee to get it repaired. Best to stop it before it happens.

The tires are a bit old and due for changing. There’s some tread left on them but it’s getting closer to the wear bar than I’d like. Maybe 2-3k left on them. I’ll change them out with some Kumho all weathers. I also gave it an oil/filter change, replaced the coolant, and brake fluid.

@ok4450, I’ve been driving and E90 328i as of recently, but I do remember that the TDI always seemed to have more throttle left at highway speeds of 80mph and a bit more torque. Perhaps it just needs more driving around, but it has been a long time since I had a good engine cleaning or anyone check out the turbo. Both were done last at 130k and it’s probably overdue. These TDI’s run pretty dirty.

@insightful‌, sorry, I just meant brake fluid, not brake pain. One too many beers whilst posting.

Around the block it seemed to be running strong, however once I hit the highway it takes forever to reach speeds of 70mph. I also noticed the distinct lack of any turbo sound that I remember hearing in the past. I’m going to have to probably check all of the hoses leading to and from the turbo. I can definitely tell that I’m not receiving any boost. Could be an N75 valve that’s stuck or that the actuator housing for the wastegate isn’t full of oil. I really don’t want to have to rebuild a turbo, because I know it’s not for the faint of heart.