Future-Proofing My New-To-Me 2004 TDI

Hey everyone! A few months back I purchased my first TDI - a 2004 Jetta GLS 5-SPD TDI. I bought it totaled from an insurance auction out of Texas - it's in phenomenal shape inside and out and has 158,000 on the odo. The car isn't quite put back together yet but before I start driving it full time, I want to make sure I cover any mechanical needs the car might have.

This car has the BEW 1.9 PD engine which starts very quickly, sounds great and seems to run perfectly. I will say that this is my first VW diesel coming from a history of owning Mercedes-Benz diesels so I'm not too familiar with its quirks and shortcomings, but I have done a lot of reading.

So, with that said, what should I look for in terms of maintenance or preventative-maintenance to cover myself? I saw where some people have had oil cooler gaskets fail and have lost oil pressure. That was on older variations of the TDI, but I want to make sure I never experience such a thing. Since the car came from an insurance auction, I don't know much about the history of the car, but it's obvious that it has been loved and taken care of. The engine bay is very clean and there aren't any visible oil leaks on the front of the engine, anyway. Since I have the front of the car apart for paint, I have noticed oil seeping around the charge pipe/intercooler joint on either side - it has left a small oil drip on the ground after a few weeks of sitting. I'll be pulling that all apart for cleaning before being driven full-time. The previous owner installed a 'doggie collar' kit on the intake with what appears to be a new VW anti-shudder valve.

Anyways, I'll post some pictures of the car when I got it (before I took it apart) so you guys can see just how light the damage was... can't believe it was 'totaled.' I feel like I stole it for what I paid

First thing I'd do is replace the timing belt system. If it was done on schedule it's due, and otherwise it's overdue. And since you don't have any service history, it's far better to be safe. Pull the valve cover and inspect the camshaft, too, as it may be worn. BEW engines are less prone to cam wear than other PD engines, but they do wear out if the wrong oil is used.

Second, there's lots of debate here about what oil to use in your car, so you can make your own decision. VW certification is 505.01, although some people use oil that's not VW certified. What's important is to use a 5w40, or a 5w30 that has a top number close to 40, like Total Quartz INEO. This will help prevent cam wear.

You should probably invest in a VCDS diagnostic tool if you plan to keep the car long term. It'll be really helpful in diagnosing any issues and save its cost many times over. To that end, once you get it put together I'd run some boost logs to make sure your turbo and vacuum system is working properly. There shouldn't be much oil accumulating in your intercooler, so if there's a lot you may have a boost problem. However, the seals on the intercooler piping in your car can wear, so you may want to replace those.

I wouldn't worry about losing oil pressure with leaking oil cooler seals, you'll have plenty of warning. If they're not leaking don't worry about it.

Also, make sure the in tank lift pump is operating. They're a common failure item, and the car will run without it, but it'll eventually kill the tandem pump at the end of the camshaft.

And if you need glow plugs you'll have to figure out what to put in the car. There have been multiple glow-plug recalls on your car which include re-flashing the ECU. You can call a dealer with your VIN to find out if your car was recalled, how many times, and if the work was done, to help you determine what plugs you need.

The timing belt is the urgent item. After that you'll have time to sort things out.

Enjoy the car!

^ What he said!

(Back in Ohio and after a wash)




It cracked me up how Copart put plastic over the driver's window... it's clearly not broken...? ANYWAYS, it was by FAR the best looking MK.IV on the site and even better than 90% of the cars I could've bought locally. I'm very happy.

IndigoBlueWagon said:

First thing I'd do is replace the timing belt system. If it was done on schedule it's due, and otherwise it's overdue. And since you don't have any service history, it's far better to be safe. Pull the valve cover and inspect the camshaft, too, as it may be worn. BEW engines are less prone to cam wear than other PD engines, but they do wear out if the wrong oil is used.

Second, there's lots of debate here about what oil to use in your car, so you can make your own decision. VW certification is 505.01, although some people use oil that's not VW certified. What's important is to use a 5w40, or a 5w30 that has a top number close to 40, like Total Quartz INEO. This will help prevent cam wear.

You should probably invest in a VCDS diagnostic tool if you plan to keep the car long term. It'll be really helpful in diagnosing any issues and save its cost many times over. To that end, once you get it put together I'd run some boost logs to make sure your turbo and vacuum system is working properly. There shouldn't be much oil accumulating in your intercooler, so if there's a lot you may have a boost problem. However, the seals on the intercooler piping in your car can wear, so you may want to replace those.

I wouldn't worry about losing oil pressure with leaking oil cooler seals, you'll have plenty of warning. If they're not leaking don't worry about it.

Also, make sure the in tank lift pump is operating. They're a common failure item, and the car will run without it, but it'll eventually kill the tandem pump at the end of the camshaft.

And if you need glow plugs you'll have to figure out what to put in the car. There have been multiple glow-plug recalls on your car which include re-flashing the ECU. You can call a dealer with your VIN to find out if your car was recalled, how many times, and if the work was done, to help you determine what plugs you need.

The timing belt is the urgent item. After that you'll have time to sort things out.

Enjoy the car!

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Wow, thank you so much for the response! In my mind, the first course of action would certainly be the timing belt system. Like you said, I really have no idea when it was done last and I'd like to have it done just for peace of mind's sake (at the very least).

I haven't changed it yet, but I did buy an oil change kit from IDParts. I chose the Pentosin 5W-40 which came highly recommended and I believe is 505.01 certified.

The bit on the in-tank pump is very intriguing... haven't read too much on that. Is there a good way to ensure that it is working properly?

Lastly, I did read some about the car's glow plugs. Before it got cold here, I was frustrated and thought that the harness or relay was bad and/or failing because the light went out so quickly -- silly me, Im used to my '83 Benz's glow plugs taking 10+ seconds to go out, hah! Not a good benchmark. Anyways, even with temps dipping below 20 degrees, the car fires right up like it does in 90 degree heat.

Thanks so much!

IBW covered it pretty well. I was going to suggest Pentosin but it looks like your'e good there. idparts has timing belt kits also. As for the lift pump, turn the key on like your'e doing the glow plug, do you hear a small humm or squish from under the back seat? If you do the pump is working.


Love those southern rust free cars.

Consider one of these: https://www.evolutionimport.com/atlas-skid-plate-kit-for-beetle-golf-jetta-iv-p/a3002.htm

The oil pan hangs pretty low on these cars and can get a hole knocked in it pretty easily. It's just brittle cast aluminum. A thick skid plate will protect against that.

Damn that's a clean looking one. I heard something about the camshafts like to prematurely wear on the PD engines. Never looked into it too much since I mostly rock the VE engines. Treat her well!

Yes, put come metal underneath, there are new or like new Panzer skid plates in the classifieds.
Being more of a tree hugger type, I hate to recommend this, but eliminate the EGR and chip it.

That's a nice looking car.

Good looking car. If you decide to tune it, I would recommend a dynamic EGR rather than a delete on a PD.


Hard to believe that thing was totaled.

mjydrafter said:

Good looking car. If you decide to tune it, I would recommend a dynamic EGR rather than a delete on a PD.


Hard to believe that thing was totaled.

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Chances are they quoted bumper and fender, probably new, plus cost of R&R and materials, could easily be $2000

I was rear ended in my wagon, just for the bumper and materials it was almost $900, and silver is cheaper than black.

My son's was pretty obviously totaled, but the guy looked around it way more than I thought he would.


I would guess airbag deployment would total just about any older car. They probably won't let you use a junkyard airbag to rebuild...LOL

CHECK FOR LEAKS. water leaks into the cabin are a royal pain and common enough that I'd correct every TDI I purchase from this generation.

Mine was immaculate with only 76k miles but leaked in several places. Sunroof, doors...

If your climate doesn't include rain no sweat.
There was even a service bulletin for sunroof drain retrofit... Lol.


Sent from my Moto G (5S) Plus using Tapatalk

Rain leaks aren't that bad, there's only two places I've found that leak. One being the sunroof vents being plugged, the other would be the bulkhead connector under the cowl panel. I've heard of the upper half of the hvac box leaking, my wife's passat did that, just sealed it up and no more leaks.

Nero Morg said:

Chances are they quoted bumper and fender, probably new, plus cost of R&R and materials, could easily be $2000
I was rear ended in my wagon, just for the bumper and materials it was almost $900, and silver is cheaper than black.

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After I saw the car in person, I knew why it was totaled. As great as it looks in pictures, and thankfully none of the damage was structural (in ANY way), the driver's curtain bag was blown along with the driver's seat bag. I replaced both with pick'n'pull units, so the interior is as good as new. I also snagged both fenders and a bumper cover which is all being painted next week.

Either way, I don't think I did too bad for a thousand bucks... most of the local examples had double the mileage, looked awful and were starting to rust - not to mention I had a hard time finding a decent one for under $5K.

All it cost me was a trip to Dallas, haha!

Figit090 said:

CHECK FOR LEAKS. water leaks into the cabin are a royal pain and common enough that I'd correct every TDI I purchase from this generation.

Mine was immaculate with only 76k miles but leaked in several places. Sunroof, doors...

If your climate doesn't include rain no sweat.
There was even a service bulletin for sunroof drain retrofit... Lol.


Sent from my Moto G (5S) Plus using Tapatalk

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HMMMM I'll have to double-check my drains but I know the car is dry inside. I know all too well about interior leaks... 2012 Focus - sunroof leaks. 2004 E500 wagon - something leaks(?). '83 Benz 300D... windshield leaks. Naturally, I felt all the carpets and mercifully, it's dry as a bone. I intend to keep it that way.

My '99.5 Golf is the first VW I've owned with any kind of a leak problem. It was multiple things: A broken mirror mount, a broken flange on the cabin filter cover, and worn gaskets that run along the top of the doors. First two are fixed, and I'm chasing down the passenger side gasket. Even at dealer wholesale they're not cheap, and the '99.5 Golf ones are technically NLA. I even had to have the later ones red labeled from Germany. Sometimes it helps to spend a lot of money at the dealer.

I almost forgot; good idea to pick up some replacement regulator parts for the windows for the inevitable time they break and drop your glass into the door panel...

VW's new design isn't just the old teflon/slippery white plastic that gets brittle with age, it has hard brown plastic and a better overall design. I bought metal replacements from regulatorfix but decided I didn't want them after I got my updated VW parts that fit better.

Nero Morg said:

Rain leaks aren't that bad, there's only two places I've found that leak. One being the sunroof vents being plugged, the other would be the bulkhead connector under the cowl panel. I've heard of the upper half of the hvac box leaking, my wife's passat did that, just sealed it up and no more leaks.

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LOL Do you live in a wet climate?
If you care about not smelling mold, meldew, and dying wet-dog smell, leaks ARE bad. One season of leaks under a heavy duty rubber floormat like the ones I have (VW upgraded floormats, pure rubber) could spell disaster for any carpet.
Try a door card leak into the rear passenger footwell that doesn't show up for a few weeks until it's traveled forward into the driver's footwell because the rear is completely filled with over a GALLON of rain water. When your floor mats don't allow evaporation, it all stays under there, festering, lol.
I was lucky I didn't have to replace my entire carpet and sound deadening pad because of that damn leak. I DID have to rip it up along the entire driver's side trim and put a fan and towels under my carpet for a week; COMPLETELY rip apart my doors to reseal the failed regulator moisture seals, AND fix the regulators that simultaneously broke during that procedure, but other than that, no... not that bad.

It's not something to freak out about, but until you know your car doesn't leak, assume it's a potential risk. 15 years on what I feel is a less than perfect sealing design takes it's toll. For example, the foam regulator seals...those should be butyl tape, not water permeable open-cell foam....

The sunroof drains were poorly designed, door seals are different and IMO worse than many door-in-frame designs (these shut on TOP of the frame, with several big seals) and the ECU and air boxes are prone to leaking from water running off the windshield. if you get REALLY unlucky they could all leak...lol.

Yeah I live in northern Oregon, rainy town over here lol I've had to fix water leaks on the wife's B5, my first MKIV, my MKV, and on my current MKIV wagon. Had to replace the TCM FOUR times on the B5 due to water. Sure it's frustrating but less frustrating than trying to do a heater core on the B5.