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300 tdi fuel injector replacement (HOW TO)

29K views 38 replies 19 participants last post by  TechN9NETY 
#1 ·
So, tackled the fuel injector replacement today...first, let me say that it was ridiculously easy. I tend to "overthink" my projects before doing them, and this was no exception - but it was uncessary.

I will also say that it was worth it's weight in gold - quieted the engine right down. Not that it was deafening or anything prior, but I was just starting to get a slight "hammering" on the engine as is notorious for tired injectors. After replacement noticed an immediate sound reduction at idle, and also at highway speed (and everywhere in between). I can hear the boost kick in clear as day on the highway now, whereas before it was getting overshadowed by the engine noise. I honestly can't believe it...money well spent. Looking forward to seeing what this does to my fuel economy, which was down to 22-23mpg (though not bad for a 110 with terrible aerodynamics and 235/85-16 KM2s).

So here's a play-by-play best as I can recall, with PICTURES BELOW matching up to each numbered step:

1) Remove the hood - just helps to make more room under the hood for working.

2) Before getting started, CLEAN the engine around the injectors thoroughly...you don't want any gunk/etc falling down into the injector holes once you remove everything. I had recently degreased my engine so it wasn't too bad, but hit it with Brakleen anyhow to get any residue off.

3) Crack the FUEL SPILL RAIL bolts (I think they were 12mm), but be gentle - you don't want to snap/strip these, and they shouldn't be on there too hard anyhow. Start with one and work your way down as you'll be moving the entire rail out of the way.

4) Move the spill rail out of the way once all the bolts are undone.

5) There is a bracket/plate that holds each of the injectors in place, and each plate is held down by a nut fastened to a stud. Undo each of these and remove the nut (NOTE FOR LATER: when putting these back ON, be careful not to over-torque them...I cracked one of the studs on reassembly - but it was a quick trip to the hardware store for a replacement but could have been avoided).

6) Once each nut is removed on the bracket/plate, move to the fuel pipe connection at the top of the injector. Likewise, crack each one first - being gentle - and then remove each pipe from the injector. Be careful just to gently move them to the side, keeping in mind that the pipe goes directly to the fuel pump and is a hard line so you want to make sure not to bend/kink these. But moving them out of the way will allow you enough room to work for injector removal.

7) Pic of the injector once everything is disconnected.

8) The next step is to see if the injector is "stuck" to the block, or if it moves freely and *hopefully* will come out. I put a 15mm wrench on the injector and gently wiggled everything back and forth to check for movement and ensure that the injector would come free easily. I lucked out, each injector moved back and forth without a problem - though from my preliminary reading "stuck" injectors can certainly be an issue. Other options if this happens are: a) affix a slide hammer to the threaded end of the injector and remove...this is the preferred method, or b) once the injector is unhooked you can use the engine "compression" by turning it over to shoot the injector out...BUT this is not recommended, can be dangerous, and if undertaken one must put a heavy blanket/etc over each injector to absorb the injector as it shoots out - again NOT recommended and I take no responsibility for issues with this.

9) Once each injector was unhooked and I verified that each was wiggling and looked loose enough to remove without issue, I simply put a pair of vice grips on each to get some upward leverage and wiggled it up and out. During this motion, the bracket/plate that holds each injector in place will also work it's way up and eventually you'll be able to slip this plate free once it clears the mounting stud that each holding nut affixes to (but you'll recall we had previously removed each nut from the studs).

10) Pic of the plate/bracket that holds the injector in place coming free.

11) If you're lucky - like I was - your injector will pull free and come right out as shown here.

12) Make sure the injector has the copper washer on the end of it, you don't want this to accidentally be stuck down in the injector hole on the block otherwise you'll have a leaky injector gauranteed.

13) Get your new injector out and ready to go in.

14) Slip a new copper washer on the injector...you DEFINITELY want to put on new washers, do NOT recycle the old ones or they may be prone to leak, causing you more headaches than the $0.50 for each new washer.

15) I used a dab of grease on the copper washer before putting it on the injector in order to help it stay put while I inserted it back into the injector port in the block - keep in mind you're turning this upside down so you don't want the copper washer to slip off and fall into the injector hole since fishing it back out would be a pain in the arse, so the grease is just helping to fight gravity and keep it stuck to the injector.

16) Speaking of copper washers, each bolt on the fuel spill rail (taken off in step 3) has two copper washers on each bolt, one on the outside and one on the inside as shown here. Make sure to likewise replace each of these washers as well.

THAT'S IT! Essentially, reverse the steps slipping the new injector into each port, hook everything back up, snug up all bolts/etc, and you're all set. While you're in there, you may want to inspect the fuel spill rail rubber tubing (with the cloth sleeve) to make sure it is in good shape. Mine looked fine, and I opted not to replace it...though to be cautious I probably should have and will in the near future - but this can be replaced without taking anthying apart so it can be done at any time.

WORD OF CAUTION #1: as I mentioned above on #5, when torquing the injector bracket/plate that holds the injector in place, these slip over a stud that protrudes from the block. There is a nut that then fits on the stud and you tighten up to keep things in place. I over-torqued mine and broke it right off...so I had to hit the hardware store for a replacement (which I think was just a standard automotive M8 stud that worked just fine). The LAST TWO PICS show the broken stud and the hole where the stud screws into the block. This probably applies to all of the above steps, take it easy and don't feel the need to "Hercules" anything like I did.

WORD OF CAUTION #2: on first test drive, I noticed one of my injectors was leaking. Took it home, popped the injector out, and there was a lot of crud that must have fallen in the hole when I removed the injector...it was caked to the copper washer and was preventing it from making a good seal. I cleaned everything off, reassembled, and it didn't leak a drop after that.

All-in-all, if I hadn't broken the stud I probably would have been done with this in less than an hour from start to finish. Honestly, it was unbelievably easy and straightforward - and again I notice positive results from the new injectors right away. I highly recommend it for anyone that is in the 70k-80k mileage range like I was.

If there's anything I missed or something that people would like to add, feel free - just figured this may help others that are contemplating an injector change in the near future.
 

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#4 ·
The injector bracket/plate is slightly curved, convex side goes upright. And the nut that holds this bracket/plate (and the injector) tight has to be torqued to 25 N.m.

The bolts of the fuel spill rails to injectors are torqued to 10 N.m. and the top injector nut (where the diesel line goes into the injector) should be torqued to 28 N.m.

My 2 cents to an allready excellent post!

Cheers,
 
#5 ·
Nice work Santiago...obviously I did NOT have those torque details, or I wouldn't have snapped the stud mount. Plus I was being lazy and used a 1/2" drive so probably another reason I snapped it off - but thanks for adding those, that will definitely come in helpful for someone (or me the next time around : ).
 
#7 ·
Thanks Steve.

Actually, as happens with most of my projects I actually ended up with an extra set of new injectors that I'd be willing to part with (since I plan to rebuild and keep my old ones as "spares" since they all came out fine and didn't get destroyed).

Contact me via email jason lavender (all one word) at g mail dot com.
 
#10 ·
Don't think it matters.... whenever I've changed them, i've just dropped the washer in whatever way it lands.

A couple of other tips:

A dab of grease on the flange of the injector will stick the washer to it, enabling you to carefully position the injector & washer down into the head easily.

If the old injector is stuck, then a slide hammer with a suitable adaptor works a treat.... I had to do this to an old engine I had once.
 
#12 ·
It is important to have new washers. These are crush washers and once used may not seal proper again when re-used. I have had two head jobs now where the injector has not wanted to come out of the hole. A couple of tricks with a slide hammer on one and sending the head in a hot bath to try to release it. The can get stuck as time goes on.
 
#13 ·
OK, the copper washers on the factory installed injectors had the ridge facing the injectors. The whole job is quite simple. Spent most of the time on the job cleaning out holes/ports that the injectors slide into. Total time spent, less than 1 hour.
 
#17 ·
So its been about 3 years and 4 months (around 11,778 miles) since I installed new injectors. How often is it recommended that you replace them? If not a complete replacement is recommended, is a soaking or nozzle replacement in order? Just curious about the recommended service interval.
 
#18 ·
Well, I know from a replacement standpoint probably 80-90K if I recall...so obviously no need to do that! I don't *think* there's any maintenance/cleaning you can do on them, but I'll let others speak to that.

However, if you're at around 12K miles you may want to adjust your valves...that's recommended about every 12K and made a big difference when I did it.
 
#20 ·
Yes, something like 80000 miles. They can't really be cleaned (despite some claims). If you have high quality fuel filtration, the nozzles will go longer.
 
#23 ·
Mine just fell off when I pulled the banjo bolt out. Had to track it down since I made the mistake of not ordering extra $0.05 washers. I realize time is of the essence for you right now, but maybe order some new banjo bolts and copper washers now (they're not expensive) while you try to get the old ones separated??
 
#27 ·
Yes, I used a tiny flat screw driver to get under it, then carefully bent it up enough to grab it with pliers. Then I was able to use a socket on the bolt to back it out. Hope I didn't score the bolt, or the fitting, too much. Takes a while to coax it out, but now I'm going to try to get the other three.
 
#28 · (Edited)
For anyone removing injectors to rebuild if you follow the steps in post 1 you will likely ruin the cores.
I realize this was a non-issue for Jason because he was installing new injectors.
BUT
If you apply this to 200TDI injectors, you'll learn an expensive lesson:
DO NOT put a wrench over the area where the spill over line banjo seats or use vise grips to extract the injector core as it will gouge the housing and prevent the spill over line crush washer from seating to a flat surface.
The gouges from the wrench and vice grips will act as a leak channel.
We can sometimes have this machined, but the setup is expensive and generally costs between $50 and $100.
DO NOT move the wrench back and forth...
Because if the injector unscrews and you tighten it again most likely the internals will be damaged and or broken.
Over tightening the injector has greater consequences than severing the head hold down stud, it will crack the nut that holds the injector nozzle in place and render the injector useless.
 
#29 · (Edited)
I've been lucky enough that the injectors I pulled last week were all loose once the bracket was taken off. All came out by hand.

Are you suggesting, though, that doing what is shown here: HERE ...is not so good, or that using "vice grips" is the wrong way to do it? I was prepared to use a standard spanner on mine, before I realized they were all free anyway.
 
#30 ·
That is a brilliant way to extract an injector.
Note that when the injector was grabbed with pliers that it was after a rag was placed over the injector to insulate the metal on metal scenario.

In the absence of a slide hammer with the proper fittings, this is 1000 times better than a wrench and vice grips.

IF YOU WANT TO SAVE THE CORE!
 
#32 ·
I realize this was a non-issue for Jason because he was installing new injectors.

In the absence of a slide hammer with the proper fittings, this is 1000 times better than a wrench and vice grips.

IF YOU WANT TO SAVE THE CORE!
This write-up from 2011 was back when 300 injectors were $80/each for brand new Bosch....$80! Hell, I think those old ones got tossed in the trash or given away! But yeah, I wasn't too worried about reusing the cores since new ones were in-hand and cheap as heck (at that time)....now they are hens teeth!
 
#34 ·
Because I know my truck, I'm preparing for the worst. My questions:

1. Besides spraying brake clean down in the holes and thoroughly spraying them as clean as possible before removing the injectors. How do you clean out the holes, especially after the injector is removed? Steal wool? Plug the hole with an earplug or something and just clean it with more brake clean and pipe cleaners?

2. All dimensions metric? Pick up a set of metric crows feet to get this all snugged up properly?

Thanks
 
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