Mercedes Vito Injector Black Death

[joboco]

Sorry if anyone considers this a thread hijack, but I have the same problem. Threads on number 3 injector hold down bolt stripped in the head. I am contemplating using a sure-sert M6 x 1.00 x 9.5mm long insert. Is this considered a good repair. I can't take my jeep to a repair shop as the nearest one to me is 75 miles away. So where I live you either do it yourself or forget it. What are your thought on this one guys.
Any advise would be gratefully received.

 

[Steve@Avantgarde]

The best repair is the one I mentioned at the start of this thread.

 

[dadiaction]

Hi
I'm up for my second injector seat repair. What I can't find is the tension to set the stretch bolt at- from memory it was 8Nm.
Can you please advise??
Cheers, Adam.

Seen worse than this!!

The best way is to get the engine really hot, you can run it without the manifold on to do this, it will be fine. The carbon will go very gooey when hot, this is the best time to remove it. From then on carb cleaner or mr muscle over cleaner works very well to get the rest off, but beware its very corrosive and will melt any rubber on the injector wires, plugs or protective sheething around the loom.

Once clean get the engine hot again and remove the injectors, if they are stuck, you will need a special puller to remove them which requires stripping the injector tops in situ.

Looking at the picture it looks as if some monkey has poorly repaired it before using a high tensile steel bolt tapped out to M8. This repair does not work if the original bolts snap or threads are damaged. The simple reason is head is alloy which expands slightly when hot, the steel bolt will then loose torque effectively loosening the seal on the injector. The bolts used are M6 stretch bolts used to cope with this proceedure.

There are companies that will do an in-situ repair to make it as good as the original, I use Price Bros in Bristol who are masters at these.

 

[bob 6600]

Hi
I'm up for my second injector seat repair. What I can't find is the tension to set the stretch bolt at- from memory it was 8Nm.
Can you please advise??
Cheers, Adam.

It was answered here for you

http://forums.mercedesclub.org.uk/showthread.php?t=76958&page=2

 

[m3gt2]

Seen worse than this!!

The best way is to get the engine really hot, you can run it without the manifold on to do this, it will be fine. The carbon will go very gooey when hot, this is the best time to remove it. From then on carb cleaner or mr muscle over cleaner works very well to get the rest off, but beware its very corrosive and will melt any rubber on the injector wires, plugs or protective sheething around the loom.

Once clean get the engine hot again and remove the injectors, if they are stuck, you will need a special puller to remove them which requires stripping the injector tops in situ.

Looking at the picture it looks as if some monkey has poorly repaired it before using a high tensile steel bolt tapped out to M8. This repair does not work if the original bolts snap or threads are damaged. The simple reason is head is alloy which expands slightly when hot, the steel bolt will then loose torque effectively loosening the seal on the injector. The bolts used are M6 stretch bolts used to cope with this proceedure.

There are companies that will do an in-situ repair to make it as good as the original, I use Price Bros in Bristol who are masters at these.

Steve, do you have an idea how much Price Bros charge? Got an injector leaking that has been drilled out before so would like it doing properly! Thanks

 

[Laura Howard]

Seen worse than this!!

The best way is to get the engine really hot, you can run it without the manifold on to do this, it will be fine. The carbon will go very gooey when hot, this is the best time to remove it. From then on carb cleaner or mr muscle over cleaner works very well to get the rest off, but beware its very corrosive and will melt any rubber on the injector wires, plugs or protective sheething around the loom.

Once clean get the engine hot again and remove the injectors, if they are stuck, you will need a special puller to remove them which requires stripping the injector tops in situ.

Looking at the picture it looks as if some monkey has poorly repaired it before using a high tensile steel bolt tapped out to M8. This repair does not work if the original bolts snap or threads are damaged. The simple reason is head is alloy which expands slightly when hot, the steel bolt will then loose torque effectively loosening the seal on the injector. The bolts used are M6 stretch bolts used to cope with this proceedure.

There are companies that will do an in-situ repair to make it as good as the original, I use Price Bros in Bristol who are masters at these.

Hi all, i cleaned the injectors but getting the M6 bolt back in proves to be difficult. There are no threads left at the top but there are some at the bottom. Please advise if I use threading rod would be a good repair? Unfortunately the car is in bits so I can't drive it to a garage. Thank you.

 

[mercedes13156]

Hi. Steve's advice is rock solid, if you can get your car to him, or to someone who can do the repair like he says. I'm 400 miles away and I've had to do a couple of these repairs on two previous C220CDi engines. Steve gave me the very same advice but I had to get the car back on the road for Monday morning. Getting the engine really hot does make the black goo flexible and you can prise most of it out with a screwdriver if you're careful. Carb cleaner gets rid of the rest on a cold engine.

Using a 40mm M8 Bolt with a timesert is OK but it needs to be an allen bolt because there's no room for a hex head. It goes in at 8Nm then add two quarter turns. It will quickly lose its torque and loosen off. It will leak again. All as predicted, mine did. I took it to bits again and applied a smear of threadlock to the bolt and it held for many thousands of miles. That's not what Steve would recommend for a spot on professional job, but it worked.

Please bear in mind that Steve runs a professional organisation, providing top class repairs for which he charges the going rate. He has a reputation to lose and an insurance policy to pay for and a living to make. (Judging by his car collection, he's doing OK at it.) His opinion is that if you want it done right, this is the way I do it when I'm charging people money for the service. Quite right! Imagine he gave you the advice that I just did, saying give it bit of threadlock, it'll be fine. He gets some numpty turning up the following week with the black death and a request that he just bodges it up like wot it sez on the forum, innit? Steve bodges it up and it fails, numpty returns and demands recourse. Numpty spreads it about that Steve runs a bit of a fly by night organisation. Everyone believes the bad things they hear. Steve's business / reputation / living ..... toast!

I think we get some great access to Steve's expertise, let's use it as it's intended.

Rant over!

 

[Westheath]

Using a 40mm M8 Bolt with a timesert is OK but it needs to be an allen bolt because there's no room for a hex head. It goes in at 8Nm then add two quarter turns. It will quickly lose its torque and loosen off. It will leak again. All as predicted, mine did. I took it to bits again and applied a smear of threadlock to the bolt and it held for many thousands of miles. That's not what Steve would recommend for a spot on professional job, but it worked.

That was never tight enough,
it should be at least double the torque
and at least 2 half turns using the TimeSert repair method.

Like any other normal manufacturer does with their injector retaining bolts

 

[mercedes13156]

I get your point. I've seen injectors properly screwed down into cast iron heads. For me, it was all about risk management. What's the risk of bu%%ering this up completely?

However, the light touch (as Steve's advice) worked for me! That injector lasted until I sold the car and for all I know is still doing its thing years after I sold it. Fact is that I was banging a steel bolt into an aluminium head that had already stripped a very fine thread. I wasn't about to strip a recut thread in case it ruined the head. That would have meant that I wasn't taking it to work the following morning.