1993 140 w/603.... using oil

[JMH]

Okay, I will now admit my regret at getting rid of the venerable 1984 Turbo 300D.

I succumbed to the good looks of the newer 1993 300SD. I heard the bent rod comments & the electrical gremlins that plague these models. But this car drove sooo nice, had so much power, started first time every time the 3-5 times I dropped in on the used car lot and started it from the cold. All the electrical stuff works save for the trunk close assist.

After I bought it in August, it just ran a little rougher than I knew it should. So I had the head pulled, and found that the head was not torqued to specs on the #1 cylinder....... so it was leaking oil around the gasket. I saw the gasket so I know the shop told me the truth. So while it was off, had it slightly machined, new valve seals installed and new hydraulic lifters too.
I had it compression/leak tested. It spec'd out after the head was done. While the head was off, the pistons all spec'd out at the top of the block so they said it is not a "rod bender"......at least not at that point. I bought it with about 93k miles on it, now has about 103k.

I drive at a minimum 1,000 miles per week. This rascal uses about 1-2 quarts per week at that mileage.... still. And when I floor it to accelerate/pass, it emits a huge plume of dark gray smoke......

Why does it use so much oil? Is there anything wrong (other than the expense) of just keeping to pour the oil to it?

Looking for some direction here, this just seems bizarre... are the rings bad? Valve seal job bad? Turbo pulling oil? Crank ventilation out of whack? Is the IP overfueling it and washing the cylinders? I am stumped.

Even still, it gets about 23 mpg no matter how hard I run it. Not bad for a big sedan...... and not too different from the old 300D...

Thanks in advance for the assistance,

JMH

PS:The shop where I take it has done work on all of my European vehicles for almost 20 years; have never done anything to make me not trust them.

[DslBnz]

You seem to quite well versed in those areas so I will tell you in detail about my 350's symptoms, and what led it to where it is right now: Still unknown problem, but lack of compression.

I first posted in August of 2003.

http://www.peachparts.com/shopforum/showthread.php?t=73746&highlight=stage+engine

It appeared that the oil consumption and the rough running had been reduced substantially. It wasn't perfect, but I remained optimistic.

That winter, the 350SD started in -10 degree temperature with a 30 below windchill factor. No block heater, and one 30 second cycle of the plugs.

Later on I posted about my new issues with consumption had then become visible.

http://www.peachparts.com/shopforum/showthread.php?t=111514&highlight=350SD+oil+consumption
http://www.peachparts.com/shopforum/showthread.php?t=111512&highlight=350SD+oil+consumption

I am down to this: Either a cracked piston ring or bent rod ovaling out cylinder. I know when I put a commercial product called "SMOKE-B-GONE" compression restorer, the car was soon back to it's original shape: No smoke, less oil consumption, and a smooth idle.

[JMH]

I listened to the soundbytes you put on here. Mine has a clack at idle but as soon as you advance the throttle the slightest bit, it goes away. Sometimes as idle it doesn't clack... almost depends on what the fuel quality is. If I run injector cleaner or some marvel mystery oil through it, it pipes right down. I changed the oil yesterday and to my glee, there was oil in the underneath panel. I never thought I would be glad to see a leak but I was. It was nowhere near as much as has been burned but it definitely had drips on the intake side, around the IP...... which I also had sent in when I did the head and had it redone too..... I think I will check the turbo cross over myself and if it is not full of oil and the turbo blowing oil, then back to the shop it goes to get checked out again.......they'll hate to see me coming but that's tough. I want it right and I think it can be made right.....

When I changed the oil yesterday, I put in some of that syrup stuff that is to stop smoke/oil burn/increase compression. I could smell it burning as I let the car sit at idle. Finally that pungent odor went away somewhat so I'm hoping to see how this works out if it will stop the burn for awhile.

Frustrating but otherwise, I love the car. But if it doesn't get fixed, I'm going to find a little old lady that wants to sell her immaculate black 85 300SD with 50,000 miles on it and perfect black leather interior!!

JMH

[rdanz]

What can cause the oil burning in the 603 is when the rods bend , once a rod bends it puts pressure on one side of the cylinder wall causing the cylinder to become out of round and then the oil seeps by the rings.What I'm afraid you need is a complete rebuild, no additives will cure this. If you really love the car and want to spend around $6000. plus labor it will run better than new.
Good luck

[JMH]

RDanz,
With all due respect, I don't see how the piston could travel all the way to the top of the block (i.e. is within spec) and yet be out of round due to bent rod to cause oil to get by...... maybe you are right... I thought there might be some unconventional wisdom here that would show me where we are missing the mark/have not yet considered so I can get this problem resolved.

Your thoughts on the piston at the top vs. bent rod possibility?

I do appreciate your thoughts and feedback. Really curious to get your thoughts on the piston at the top vs. bentrod theories.....

Many thanks,
JMH

[Hatterasguy]

I would pull the cross over and see if the turbo is leaking. Also try to seal up any leaks you can find. 1 quart every 500 is getting to be alot, I would suspect the bottom end maybe going south. Run it until it blows you need a new short block anyway.

[Brian Carlton]

Originally Posted by JMH

Your thoughts on the piston at the top vs. bent rod possibility?

You have a very interesting case here. You have measured the tops of the pistons and confirmed that each one is properly reaching the top of its stroke. This rules out the possibility of a bent connecting rod. Of course, it might be possible that the rod has bent in the last 10K miles, but, the oil consumption was quite high prior to removal of the head and it has not been reduced since the replacement of the head gasket.

When the head was off the vehicle, was there any replacement of valve guides or valve seals? Were these items in acceptable condition?

Is there any possibility of the turbo consuming an excessive amount of oil? Maybe you can pull the intake and see if it is flooded with oil in there.

What about blowby? Maybe you can disconnect the hose from the valve cover to the intake and run it into a bucket, underneath the hood, for awhile and see how much oil is getting sent to the intake. You would need to be able to drive the vehicle in this conditon to get any useful information. The bucket would need to be secured in some fashion down near the bottom of the block.

If none of these items appear to be the culprit, then it is possible that the oil is getting past the rings and being burnt in the combustion chambers, however, I would think that this scenario is the least likely of them all.

[JMH]

Thanks Brian.....I would suspect it's a topside issue too. Hatterasguy, I am no expert but I distinctly smell burned oil in the exhaust..... so bottomend deterioration without a bent rod would not seem to me as a likely culprit of burning oil. I will check that crossover and the oil contained therein. I have pulled the tube off the valve cover and although there is some oil in there, it's not alot.

Boy, that Turbo 300D was sure a good car...... no frills, and the AC sure sucked for Florida summers but it was the best car I've ever had, bar none.

JMH