My 190DT has an air leak by the intake manifold. At first I was hoping it was just the manifold gasket but I just cleaned it up some with brake cleaner and I could see it bubbling at the pre chambers. I think the PO removed the pre chambers. Is it possible that he reinstalled them incorrectly causing air to leak by?

Thanks,
Chris

If you have a real Pre-chamber leak you will get more than little bubbles.

If liquid (usually Fuel when you bleed the Fuel Injection Hard Lines at the Injector) gets down in the space between the Pre-chamber Ring and the Injector you will get little Bubbles like that.

The only reason I can think of for that is that when the Fuel is Injected there is a shock wave from the actual injection and the ignition of the Fuel. That vibrates through the liquid and cause it to Bubble.

If you fill up that space I was speaking of with Brake Cleaner it should mix with the Oil and Fuel that is down in there and if you keep wiping it up and reapplying the Brake Cleaner eventually it will be diluted enough that when the Brake Cleaner evaporates there will not be enough liquid down there to bubble.

That being said some People have had the Pre-chamber Ring come loose when they remove the Injectors (this will not happen on the Models with Angle Injection as the Injector does not screw into the Pre-chamber retaining ring on those).

A real Pre-chamber leak will have combustion gasses coming blowing out some have even had raw Fuel come out.

Also in the normal course of things after a Pre-chamber is installed the empty spaces between the Pre-chamber and the Cylinder Head eventually fill with Carbon and that seals them.
In order for the Pre-chamber to leak something has to be cracked, the mating surface at the top has to be warped or the Pre-chamber Retaining Ring has to be loose.

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84 300D, 82 Volvo 244Gl Diesel

Could it be the injectors are not torqued down enough or they did not replaced the heat shields? I think I am getting combustion gasses because if I accelerate and then let off, I can see some black smoke come out from somewhere near the back of the engine. Otherwise, I can just feel it and not hear it.

Thanks for your help.

the smoke is likely an exhaust leak. the bubbles are possibly from heat shield issues, possibly from vibration/heat boiling the liquid in the space.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

It seems like the leak is coming form the intake side, as I can feel it there.

I hope it is just boiling liquid or bubbles from vibration. Just paranoid with aluminum head and the PO removing the pre chambers.

As the other member said more then a few People have installed the Heat Shields upside down. In fact if you drop them in the tend to flip as the go down.

You will need to reduce this formula. If you mix one Gallon of Water with one cup of Dawn Dish Soap. This makes a bubble mix at My Wife's preschool.

Put it in a Spray Bottle and Spray it on a Cold Engine and start the Engine. If you really have a leak it is going to Bubble a lot.

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84 300D, 82 Volvo 244Gl Diesel