1995 om606 loud engine noise

[packerfan]

Can someone identify this loud pinging metallic noise while engine is running?
Sometimes the engine runs very quiet but this noise comes and goes.


https://youtu.be/dbQGx9Gs6Xw

[tjts1]

Sounds like nailing from a bad injector.

[packerfan]

Originally Posted by tjts1

Sounds like nailing from a bad injector.

I thought it might be a bad injector but my 1999 e300 makes the same noise and it has new injectors!

[jake12tech]

That's injector nailing. Even if the injectors are new it could be be getting air in somewhere from a leak, or the delivery valve seals are bad. Sometimes the springs inside the IP for the delivery valve wear out and they'll cause nailing.

[packerfan]

Originally Posted by jake12tech

That's injector nailing. Even if the injectors are new it could be be getting air in somewhere from a leak, or the delivery valve seals are bad. Sometimes the springs inside the IP for the delivery valve wear out and they'll cause nailing.

Thanks jake12tech,
How did I know you would know exactly what the problem might be and what to look for?!

[andrewjtx]

Air is your enemy in the fuel system.

The OM606 has a bundle of fuel lines with connectors & o-rings that fail over time. If your clear lines haven't been replaced in long time, I would look into that. Several threads available on that topic alone. Equally important are the rubber hoses in the mix. Check the entire plumbing for anything that looks amiss.

[jake12tech]

Originally Posted by packerfan

Thanks jake12tech,
How did I know you would know exactly what the problem might be and what to look for?!

I know my around these diesels I guess.

Check all the plastic fuel lines. If you see air at the clear line that runs to pre filter on the fuel filter housing, you definitely have a leak! The o-rings could be getting in enough air to cause that nailing. How's that power steering pump working for you I sold you?

Also, that rubber hose that's visible (may not be with your NA Intake Manfiold that's bigger than the turbo), but it runs up to I think the feed line from the tank, if that has any cracks that will cause air ingress too.

[packerfan]

Originally Posted by jake12tech

I know my around these diesels I guess.

Check all the plastic fuel lines. If you see air at the clear line that runs to pre filter on the fuel filter housing, you definitely have a leak! The o-rings could be getting in enough air to cause that nailing. How's that power steering pump working for you I sold you?

Also, that rubber hose that's visible (may not be with your NA Intake Manfiold that's bigger than the turbo), but it runs up to I think the feed line from the tank, if that has any cracks that will cause air ingress too.

power steering pump works well. time to park the '95 very reliable at over 41200 miles (winter beater rust bucket) and bring out the '99. salt is off the roads.I will check both cars for air leaks in the fuel lines and see what I find. that loud nailing noise is so annoying.

[jt20]

the valves are not seating in the head. To fix it needs a complete valve job and seat repair.

you can prove this by taking off either one of your manifolds and starting the engine.

[GregMN]

Check the belt tensioner

[Diseasel300]

That is definitely not a belt tensioner noise. If it's nailing, that's a frighteningly loud nailing too! I'd try to narrow it down to a single cylinder by cracking injector hard lines. If you can isolate the cylinder, pull the injector and test it or have it tested for pop pressure and spray pattern.

[GregMN]

Originally Posted by Diseasel300

That is definitely not a belt tensioner noise

Have you ever had a belt tensioner make that sound ?
I have. Exactly that sound. Come and goes. Hard to tell without having your hands on the car. Check it out to eliminate it as the source.

[packerfan]

Originally Posted by jt20

the valves are not seating in the head. To fix it needs a complete valve job and seat repair.

you can prove this by taking off either one of your manifolds and starting the engine.

I'm starting to wonder if you may be correct about the valves not seating. I had a member on this forum (greazer?) rebuild my injectors last year, before he rebuilt them he tested them and found one that was peeing and they pop tested all over the place, low 1600 high 2400. I put in the rebuilt injectors and replaced all of the clear lines and started the engine with the intake manifold off and let it run for a long time until all air was out of the lines. I let the car sit over night and inspected the lines in the morning to insure they were full of fuel and no air. I started the engine and let it run and every now and then you could hear a loud poping noise coming from one of the ports. the noise would come and go. pop pop pop pop then quiet for awhile and then pop pop pop pop again!

[spock505]

Mine had the exact same noise (OM606.910), worsened by a poor after market exhaust system.

I never did identify the problem but ended up fitting a 606.962 turbo head in replacement.

In my case it may have been a sluggish lifter or valve spring, hard to tell as I did so much all at the same time.

The oil I was using may have been a bit thin, 5w -40w fully synthetic.

[packerfan]

Originally Posted by spock505

Mine had the exact same noise (OM606.910), worsened by a poor after market exhaust system.

I never did identify the problem but ended up fitting a 606.962 turbo head in replacement.

In my case it may have been a sluggish lifter or valve spring, hard to tell as I did so much all at the same time.

The oil I was using may have been a bit thin, 5w -40w fully synthetic.

It's difficult to identify exactly where the noise is coming from but it is most noticeable and loudest from underneath the car.