[:@] Help [:@]

Hi all may I start by saying thank you for such a wonderful forum and fantastic info. I have been reading these forums a lot and have learned more that I thought was possible.

My Car: 1984 Mercedes 300sd Turbo Diesel - 126 body California model (I think)

History: I bought this beauty a month ago for $2000 and spent about $2000 and 2 weeks solid on the following.

* New tires and rims
* After trying to get an alignment needed new steering rod arms, done + Alignment
* New front brake assembly - The front brakes were shot and on inspection it was apparent there was 1 x 126 front brake assembly on the left, and 1 x 123 front brake assembly on the right, so I had to have that sorted out and got it all back to uniform and new pads.
* Changed transmission filter, fluid and gasket
* Changed power steering filter and fluid
* Changed Oil filter and oil
* Changed primary and secondary fuel filters
* Changed all V-Belts
* Oil pan gasket
* Diesel purge with Lubo Moly

After all this she was driving great. Starts first time, without any acceleration, No smoke, perfect idle and very little noise. Great power even on hills, and was an absolute treat to drive.

I added 5 gls of Veggie oil (New and clean from Costco) and 10 gls of Diesel and it ran and sounded even better for a week. So quiet and so clean it was just amazing to drive and I got excellent mileage. I took her on a road trip to LA and it was great until on the way home I stopped off for some fuel in a out of the way service station and within minutes I noticed a cloud of smoke following me? I figured it was perhaps mist or condensation as it was a bit of a cold night and continued to drive the hour home back to San Diego. The next day in the light of day I noticed that there was a LOT of black smoke coming out of the exhaust and a loss of power, especially on load (ie: going up hills) and even more smoke.

I suspected it was contaminated diesel and after talking to a friend he said it sounded like I got a bad batch of Diesel and could dilute it out so I removed the return fuel line into a jerry can and drained most of the fuel out and filled up the tank to 1/2 and then attempted to drive the bad fuel out. I have been driving the freeways around my home for 2 days now and the smoke seems to come and go from Terrible to just bad. I got to almost empty again and again filled it up to 1/2 with good fuel as to dilute it but it is now two half tanks on good fuel and it hasn’t really helped at all.

Now: Starts really badly and I need to rev it just to start it up. Lots of black smoke that seems worse of a night time but it might just be an illusion and definitely worse under load or hard acceleration. Loss of power, like down to 40 mph on hills that I use to roar up doing 70. A loud knocking noise at idle and low speeds. Increase in Temp with the temp gauge going well above the 80 mark where it use to never move above this. On the freeway, on the flat, doing 70 she seems to run quiet and minimal smoke and almost for a moment or two seems to be ok.

I am at my wits end and almost ready to give up. I really don’t know what to do. Most of the work above I did myself, learning from these and other forums so I’m fairly mechanical and handy but have no real experience with diesel engines or Fuel Injectors.

Is it possible that it was not contaminated diesel but just a total coincidence that something occurred around the time I filled up? Or have I done damage to the engine / Injectors by driving it in this condition? Or .....or.....or.....is it something all together different.

Please Please Help as I really need some help and advice on this. I have read that it is not that hard a job (timely yes) replacing the injector nozzles but I don’t want to go through all that if it isn’t the issue

Sorry for such a long blurb but I just wanted to be as detailed as possible.

Again Thank you all so much and any information, advice or experience as it is greatly appreciated.

Cheers James

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My first thought was lack of compression within the cylinders and a bad head gasket. However, I don't think this would occur minutes after fillup. It could be numerous possibilities, the viscosity of vegetable oil is much thicker than diesel so it's a possibility that one of the injectors or more are clogged. That would explain the knock, hard starting,black smoke and loss of powersince not all the cylinders are firing. A second possibility focusing on thehard starting could be the glow plugs, glow plug relay, orthe glow plug relay fuseneeds to bechanged. I am leaning towards the injectors and or nozzles personally.

The temp gauge is a whole separate issue and needs to be fixed immidiately before things go downhill. Check your water pump and radiatorfor any leaks. You might want to replace the thermostat for the heck of it since they're cheap, sometimes they jam open or shut.

 

Hi AMGMercedes

Thank you for such a quick and great reply. I do love my Merc and the community she has taken me into. I will never give up on her, Never

I to think its the Injectors for some reason. DieselGiant has a great walk through injector Nozzel replacement here http://www.dieselgiant.com/mercedesi...zlereplace.htm and I am thinking bout just doing it to inspect and clean the injectors just to see. I think it is a full day job but very doable. If I cant buy any nozells tomorrow is it worth it just to pull them all one by one and give them a good inspection and clean in the brake fluid to clear any gunk/junk or is it best to wait and buy new nozzels. Also I am meant to be driving to Arizona this weekend, is it bad (other than to the environment to drive it like this.

Again Cheers for your info and if ever in SD i owe u a beer :__)

 

You should replace them, especially after 25 years. Check around for prices, some of them can be high for a set. autopartswarehous.com and http://www.autohausaz.com/is where I buy my parts. Let us know how it works out

 

Yep I think so to. I have canceled my road trip this weekend (cant take the stress or agro when driving and dont want to be a polluter) and have ordered new Nozzles and flex fuel line kit from https://mercedessource.com/search/node/nozzles (I have a great relationship with these folks and they are really good and knowledgeable). All parts should be here on Tuesday and im gonna replace all fuel lines (to ensure no air is gettin in the system and it is due) and replace the Nozzles. I will post here once it is all done to let yr readers know if it resolves the issues im having (I really think and pray it will)

One last question.

The Timing chain. I have put so much love and money into her in the last month, from what ive read I should really replace the timing chain aswell as I have NO history of service or if it has ever been done. I dont really have the time (or motivation) at the moment but will schedule it in the next 6 months. How frequently do the timing chains go on these old Mercs? Do they have a history of Timing problems or is it purely a Good preventive job to do for peace of mind??

Thanks again and great job with this forum.

 

Hi the new nozzles arrived today and it was a easy pleasant job replacing them. The old nozzles were in bad shape and very clogged up with black soot/mess. Following Diesels Giants walk through I thoroughly cleaned the injectors and installed the new Nozzles.

One thing i noticed when i removed the injectors was that they had what appeared to be black engine oil on the bottom of them where they screw into the engine block. From this I can only deduce that either the piston rings have blown or the head gasket/head is blow/gone letting oil get into where it is not meant to be. Would this be consistent with the knocking, loss of power, and thick black smoke from the exhaust? Do you think i have gasket/head/ring issues or is this normal (I cant imagine)

Thank you for all your help info.

 

It shouldn't have anything blown. The most likely issue is clogging in the lines/injectors/filters due to the veggie oil. Do Not put veggie oil into your car unless you have the proper conversion kit that heats it to a minimum of 180 degrees. The car was not made to run on veggie oil. Do a search for SVO or WVO in the diesel forum and you'll come up with some resource links that give you all kinds of reasons not to do this.

Since you've already cleaned your injectors and run a couple tanks through the car, the only thing left should be cleaning out your fuel filters. Until you get all the veggie oil out of the system you may still experience trouble.