Another leaking injector seal

[fester]

Originally Posted by wadonga

was told just recently by a diesel mechanic that the water jacket is extremely close to bolt hole on our engines and that re-tapping hole was to much of a risk.
As ive never tapped before and couldnt find a diagram anywhere to confirm this, it was enough for me to leave it alone.
Not sure of the what could go wrong with re-tapping but maybe you blokes out there could shed some light.

There is no issue with retapping the hole as we are talking about retapping the same size. In essence all we are doing is cleaning the threads and sharpening them back up as they can lose definition being ally with a little corrosion and if there is still corrosion crud in them when the new bolt goes in it can strip.

The issue with the water jacket comes in if you are talking about helicoiling (or other brand names) the thread hole because it has stripped out. Then you have to either open it up and tap a bigger size or put in a helicoil to restore a thread. Either option means drilling an oversize hole which is where the risk is.

On a side not I don't think the thread pitch or size is special and it has been mentioned it is 6mm. The onyl reason I think from memory there is a factory tool for the job is due to the depth to get down to the hole is a bit much for a normal tap and holder. The tappign tool I saw was simply a tap on a longer shaft with a "T" handle. If you can get in there with a standard tap and holder then it should be fine. Don't forget to use a bottoming tap to get right to the bottom of the hole.

[wadonga]

Cheers Jason

[55zed]

The water jacket becomes an issue when the threaded hole is not cleaned full depth, as
the clamp screw can punch the bottom of the thread out unto the water jacket.
When I removed #4 clamp screw coolant came out of the hole, wasn't going to lift the
head so put thread seal on that screw when refitted. all good so far, wait until I
have to remove that injector again..

I bought a injector seat cutting set on fleabay to reseat the injectors and also was
able to use the cutter without the handle to cut the bottom of the injector where
it sits on the copper washer.
Cheers john

[SMBCJ]

Well, it's my GC's turn for Black Death. Last week I heard a slight chuffing sound from the motor and lo and behold!, Number 2 has developed telltale black specks around the injector.

I've ordered the cheapy injector flow test kit and am going to check the injectors first because if I'm going to do one, perhaps the whole lot at once is better and if the injectors need replacing......well, I'll decide what to do about that later.

Engine runs fine, strong and smooth, but I have noticed a small fuel consumption increase over the past few months. and it only makes the chuffing sound occasionally when cold.

It's coming up on 300k too, so all the fluids changing etc. and might be timely to freshen everything up.

[SMBCJ]

Well I'm glad it was number 2 and not 4 or 5!!!

That sh*t is NASTY!

Took a whole can of brake cleaner and WD40, lots of chipping and picking with pointy things and many cubic feet of compressed air to clean it all out.

Loosening the hold down clamp bolt in stages and running the engine several times for a few minutes released the injector which was absolutely caked in the gunk, but a bit of careful wire brushing in the parts washer and all good.

New washer and bolt from MB ($11), Reamer (UK lbs50) and a few beers ($12) and no more Black death!

For a non-mechanic like me, this seemed a difficult proposition but now if another case of this occurs - I'm ready!

[drover]

I have had the engine cover off for years now and check them at least once a week, so far so good, clean metal on all 5, hope it stays that way.
So did you get the injector test kit and check the flows ??? Mine has been sitting on the shelf waiting for me to use it, but I don't want to tempt fate.

[SMBCJ]

Hahaha! I don't want to tempt fate either! Should we move to Egypt?? (nearer to de Nile) and to answer your question - nope. Haven't checked the flow rate - too scared! The kit is on the shelf though.......