[e92_josh]

My N53 finally said enough is enough and isn't happy at all with it's injectors.
It's parked up for the time being while I source new ones, so decided to test the injectors that are fitted as shown below.

[IMG][/IMG]

I fitted up the injectors and cranked the car with the coil packs removed. With clean blue roll, there was fuel leaking on the tips of injectors 2 / 5 / 6.

When removing the injectors however, I found a LOT of oil on the ones that were leaking the most (injector 2 / 5 / 6).

Injector 6: Lots of oil above and below teflon seal and some just below decoupler. The oil was really dark/black and looked old.
The cylinder head/valve cover doesn't show any signs of oil dripping from a leak above.

[IMG][/IMG]

Injector 5: Again a lot of oil above and below teflon seal and around decoupler.
This oil looks fresher, so i'm inclined to think I have a leaky valve cover around here, although I couldn't see anything.

[IMG][/IMG]

Injector 2: Again lot's of oil above teflon seal but none below or around the tip. The coil packs for cylinders 2 & 3 had oil residue on the tips too, so I think that the oil I'm seeing here is from oil filling spillages.


Is oil on the tips of leaking injectors common to see?
I didn't see any oil on injectors 1 / 4, and they were also the hardest to remove (which makes sense as they were dry).

Does anyone have any recommendations for cleaning up the cylinder head?
There is oil everywhere from old valve cover leaks and spillages when topping up. Any cleaning products I should/shouldn't be using for this?

Cheers

[Dormermike]

Interesting. So the plug wells and around the injectors was all clean? Could the oil be leaking from inside the injector itself? They might be filled with oil for cooling or insulation.

What index are these?

[e92_josh]

Just finished up on the driveway:

Injector 2: Rev02
Injector 5: Rev02
Injector 6: Rev08

For Injectors 2 and 5, I can see oil in the well and i'm thinking it's oil from either the valve cover leak I had fixed last year or oil spillages from topping up.

For Injector 6 (leaking w/ black old oil) the injector well is dry with no signs of oil leaking into it.

Interestingly Injector 3 (rev07) didn't leak under my test, but was also covered in oil around the tip with old black oil too. The injector well is bone dry for this cylinder.
EDIT: Bimmerprofs mentions that typically injectors leak worst at low temperatures (as per my test above), however some will leak at higher/operational temperatures. Perhaps this injector leaks at high temps??

It'd be really interesting to know if the injectors are oil cooled, i've not heard of this before.


I've also bought and 'tested' 3 pre-owned injectors I picked up for £30 each. 2 of these don't leak under my test but 1 leaks unfortunately. So I have 5 non-leaking injectors for now.

My plan was to send these off for testing / cleaning however these bimmerprofs pages are making me re-think.

https://bimmerprofs.com/injectors-cleaned-really/
https://bimmerprofs.com/cleaning-of-...ectors-part-2/

Bloody injectors lol

[Dormermike]

Yah ignore my comment about oil filled; i seem to recall seeing a teardown of one of these injectors on youtube and it didnt have oil in it.

Oil flows all over the place, so it can be a pain to locate the source.

[0l0dom0l0]

The oil will be from the VC gasket and top ups. I had to strip the top cover off mine when I spilled a bit of oil on my last oil change and clean it all out. It goes straight down the injectors and plug holes when you miss the filler cap.

Oil below the teflon seal on cyl 2 is just from removal.

Injector 6 looks like it potentially has blow by past the teflon seal though, is it possible it was removed and the seal not replaced?

I've got index 7's in mine and haven't got any issues with them. There was a thread recently about cleaning them and the results. Will have a look for it.

[e92_josh]

Did you just give everything a wipe down with APC/degreaser?

It's very probable that the injector was removed and refitted without a new seal.

The car is a bit of a lemon tbh, with crap history regarding the injectors. I've not touched them during my ownership but the garage I bought the car from wasn't the best

What makes you suspect blow by on cylinder 6?

If there has been blow by caused by an old seal, hopefully a new one will fix it. I've heard that the bores can become ovaled??

[0l0dom0l0]

I went down the brake cleaner route but you have to be careful as it is pretty nasty. APC or degreaser is probably the better option.

I'm a little suspicious of no 6 because of the way that the tip is black continously, there is no break in the discolouration. It is just a theory but certainly possible if the seal has been re used.

I've heard of the oval bore issue too. That is usually as a result of several removal/ re installation attempts, however I imagine you'd need to be a bit of a monkey to achieve it.

The fact that you have relatively low index injectors suggests that they are originals. The index 8 has been replaced - possibly with a used part and the seal not changed?

Who knows, I wouldn't read too much into it though and a new set of seals and decouplers plus some non leaky injectors to replace the leaky ones should get you back on the road. Could keep an eye out for 3 index 11's and replace one complete bank. Then use the others in the other bank.

Don't forget to reset your adaptions when you are done replacing them- plus coding the injectors in of course.