190D noises and whatnot - PeachParts Mercedes-Benz Forum

#1 10-21-2001, 03:27 AM

Hello, I am new to this forum but I heard great things of it...

First off, I work in the IT field now, but at one time I worked at an import car dealership and acquired factory training from both Audi and Kia. My experience with VW-Audi diesels is very limited... I think only one came through our shop during the time I worked there.

However I am an avid Peugeot owner and one of my recent Pugs is a turbodiesel which I love. I'm nearly 25 now, but when I was 16 I was absolutely obsessed with diesels. My dream car at the time was a 2.5 liter Peugeot 505 turbodiesel with 5 speed trans. Quit laughing, I'm serious. I just loved the whole diesel concept, so much in fact that I talked my mom into buying an '89 M-B 190D 2.5 at a local dealership back in 1993. We got a good deal on it and she loved the car--it was perfect for her.

Well the car is still here but now has over 230k miles on the clock. An interesting problem has appeared--there is an odd ticking noise from the top end of the engine... it can be loud at times, but it is also somewhat intermittent. Honestly it sounds like a bad hydraulic lifter--as if the lifter is collapsing at times, and the valve lash goes way out of spec. But it has also been suggested that an injector is making noise intermittently. My experience with any kind of diesel engine is limited, so I was just wondering what any of you think. I should also add that she complained of the car recently having trouble maintaining 65 MPH on the highway... like a momentary loss of power--I think it coincides with the noise.

Also... this is not a Mercedes question specifically, but I thought you diesel experts may be able to help. I recently acquired my Peugeot turbodiesel--it is a 2.3 liter 4 cylinder with Bosch VE injection. This car is weird because recently it has started smoking at the oddest times. Under deceleration or very very light throttle it will smoke (dark gray-ish). 1/4 throttle to 3/4 throttle and the smoke goes away and will not come back unless I floor it. Under decel, when I coast to a stop the smoke will lightly roll out of the tailpipe for about 30 seconds or so before going clear again (if I stay at idle).

For starters, I've disconnected the EGR vacuum solenoid and made sure the EGR valve was mechanically shut (though it may leak... anything's possible). I played with the injection timing and I think it's set alright--the engine has a nice healthy diesel rap at idle and the cold startup situation seems just fine. Performance otherwise is just fine... I'm thinking an injector is opening too early, but I'm not sure...

Any ideas?

Thanks--sorry about the length

-Joe

psfred · #2 10-21-2001, 03:39 PM

Joe:

Had a family friend in DC who swore by Puegot 505 diesels -- ran about 4 of them to death commuting 50 miles each way. Got 300,000 or more miles out of all of them, some 500,000. Nice cars.

You have one or more bad tappets in teh 190D -- like hydraulic lifters except directly between the cam and valve. Known problem with these cars, you have to take the cam out to replace them. You can check to see if it is an injector by loosening the injector pressure line about 1/2 turn -- if the knock stops, it is the injector. You will spray some fuel out, and the engine will shake pretty hard, but noise is all you are interested in. Knocking injectors can be cleaned in place with Redline or Diesel Purge, etc, or removed and replaced ether from FastLane or at a Bosch shop -- about the same price either way.

The valve guide seals on the Peugot may be shot and need to be replaced. Check valve to guide clearance while you are at it, it may also need a valve job. Stuck EGR will give you HUGE clouds of smoke, strange rattling sounds in the engine, and NO power off idle -- the Volvo did this, and I eventually plated off the valve -- a new one is almost $400, too much right now.

The VE pumps are a little different than the inline pumps and can do some strange things with smoke, but unless you have a fuel line leak letting in air, I suspect valve guide seals, expecially if you get a puff of bluish gray smoke when you take off from stoplights, etc. -- classic indication of leaking valve guide seals on a diesel, along with rough initial idle and blue/white smoke on startup cold.

VE pumps are noisy, and more sensitive to injector opening pressure than the inline pumps, or maybe it is the Volvo/Audi/VW motor. An early injector will knock more. One known problem with the VE pumps is the cold start device -- it should move under stiff spring pressure -- all the way forward cold but you can push it back, all the way back hot but you can push it forward. Typical failure mode is to get stuck in the cold position, where you get no injection advance and extra, late fuel -- smoke (huge clouds of it) and poor performance.

Set the IP timing by the book (lift on piston through the bolt hole in the center of the injector lines on the front) with the cold start (if you have one) disconnected. If you set it with the cold start engaged, your timing will be very late. Early IP timing will give you extra noise and smoke at low speeds, no smoke at high speeds, rpm dependant. Slow timing will give quieter than normal engine and smoke at high speed, rpm dependant. Peugots are known for quiet diesels, so if your's now sounds like a Mack truck, you have the timing too fast by quite a bit.

Let me know if this is confusing, as you can really mess things up if you disconnect the cold start device incorrectly!

Peter

#3 10-24-2001, 11:51 PM

Good call on the valve seals... The engine used in my '82 Pug is called the XD2S and is the "early" turbodiesel which has no exhaust valve seals, but does have intake valve seals. The later "XD3T" turbodiesel had no valve seals at all... I wish I had that one right about now.

Anyway, one thing that may have prompted this valve seal leakage is my choice of oil. I believe the previous owner was using Castrol GTX 20w50. I changed the oil to Rotella T 15w40, about the same time I noticed the smokiness.

I have heard odd things of Rotella T... such as, it is more likely to leak from an older engine, etc.

I checked the oil and it was about a quart down and very runny. So, I guess that's it! I feel confident that the rings are okay since my compression test showed unusually equal and high pressures.

On to the Benz--I figure it must be the "lifters" now--I pulled the oil cap while the engine was running and could hear the sound much clearer. The cam also splashed some oil my way--oops.

You say this is a common prob for this motor? Well, the noise must be coming from them... I'd be a little more hesitant if this was a unique situation... I get all my Pug parts from Disortex in Texas, and I think they also distribute certain German parts as well... Any other sources you guys have in mind. The local Mercedes dealer, while pretty competent, charges outrageous retail prices for parts.

-Joe

psfred · #4 10-25-2001, 12:16 AM

Joe:

Check out FastLane here on MercedesShop -- seem to be very good (no personal experience, I get all my stuff at my local indy, who give me tons of free advice!)

Price is about $30 each (probably less on FastLane) for cam followers.

Synthetic oils (if that is what Rotella T is) will go down valve guides more easily than dino oils.

And check your oil trap, make sure a tube hasn't fallen off or something -- I can't be more specific cause I've never been into a Peugot diesel, but I'm sure the is an oil trap, and if it is broken, will not be trapping the oil. Check for blowby by pulling the dipstick up a bit while idling -- steady stream of gasses indicates excessive blowby. There will be some, but big clouds = trouble.

Never take the filler cap off an MB diesel while it is running (or gas engine either) -- they throw copious quantities of oil. I had oil running down the fenders when I left the filler off one time!

Peter