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1999 500SL
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Discussion Starter · #1 ·
Hi All,
I have a 1999 SL500 with 67,000 miles on it. I drive it about every few weeks and this morning it started smoking from the exhaust and is running rough. I have had the car about a year and this is the first time this issue had happened. I plan on calling my local MB shop on Monday to see what they say. I'm afraid to drive it so I don't cause any further damage. I do see one drip of what appears to be oil on the floor, but that's about it. I tried uploading a video but get a message stating file does not have an allowed extension?? My fear is an expensive repair is coming....
Thanks for any suggestions or insight.

Ed
 

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2002 SL500
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213 Posts
Rest assured, your engine is fine. That said, I'm assuming your engine's oil is being maintained.

In general, white smoke water, black fuel, white/gray blueish oil. I'm betting on fuel.

What happens when you rev the engine?
 

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1996 SL500, former 1986 560SL
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131 Posts
I agree, if your fluids have been maintained appropriately, it's probably something relatively simple in the fuel or ignition systems. It could still cost a few bucks depending on the parts (fuel pump, ignition coils etc).
🤞
 

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1999 500SL
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22 Posts
Discussion Starter · #4 ·
Thanks for your replies. Revving the engine produces a little thicker whitish possibly blue smoke.I have had the oil changed six months ago using Mobil 1 European blend, but I have put less than 100 miles since the change.
 

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1999 500SL
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Discussion Starter · #5 ·
So I just got off the phone with Huffs Automotive, who specializes in European car repair here in the Phoenix area. They installed my top cylinders. The news is not good. They say that the Engine light code stated misfire fault in cylinders five thru eight, and another code was oxygen sensor also in five thru eight. They pulled all the spark plugs and found fuel in cylinder eight. They are telling me the engine is seized due to "hydro lock" and needs replaced. The cost for a used engine is $7500!! The used engine has 75K miles on it, which is actually 8K more than my car. I have a friend who is a good mechanic that I have a call into. At this point I am not sure what to do, but safe to say, this car has turned into a money pit. Big regret with this purchase. :(
 

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1996 SL500, former 1986 560SL
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131 Posts
Sounds curious that an engine that runs (albeit badly) would be described as seized. Leaking injectors could certainly dump extra fuel into cylinders... but enough fuel to hydrolock an engine would be unusual. Excess fuel would also explain the oxygen sensor code. Hydrolock is more typically caused by lots of coolant getting into the cylinder. See what your mechanic friend has to say.
 

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1999 500SL
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Discussion Starter · #7 ·
Sounds curious that an engine that runs (albeit badly) would be described as seized. Leaking injectors could certainly dump extra fuel into cylinders... but enough fuel to hydrolock an engine would be unusual. Excess fuel would also explain the oxygen sensor code. Hydrolock is more typically caused by lots of coolant getting into the cylinder. See what your mechanic friend has to say.
Thanks Ken, that's what I thought. Just waiting for him to call me back.
 

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1999 SL600 | 2001 SL500 (sold)
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Sounds like serious bs lmao, especially if the car is still running and driving

Tell us the exact codes that were pulled. Entire bank misfires and an o2 code on that bank to me points to a simple replacement of said sensor (I’ve been there with my old SL) , but tell us the codes so we’ll be sure.

as for the smoke, check your oil level and coolant(only below 90°C!) . It will be obvious which of the two you’re burning. BTW if you’re running 0w40, get rid of that garbage. 0w40 is only to be used in winter wonderland climates. Step up to 10w40
 

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1999 500SL
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Discussion Starter · #9 ·
Guys. just so I am clear. The car would not crank when I tried to start it yesterday morning. It did make a loud pop that sounded like a misfire.I had to have it loaded on a flatbed just to get it to the shop. Still waiting for my buddy to call me. I did not get the specific codes, only what they meant per the mechanic. I do know oil levels were fine as there were less than 100 miles since the change.
 

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1996 SL500, former 1986 560SL
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131 Posts
Tell us the exact codes that were pulled. Entire bank misfires and an o2 code on that bank to me points to a simple replacement of said sensor
Good point, it could be a bad Oxygen sensor causing an over-rich condition if it's not leaking injectors (or possibly both issues).
 

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1996 SL500, former 1986 560SL
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Guys. just so I am clear. The car would not crank when I tried to start it yesterday morning. It did make a loud pop that sounded like a misfire.I had to have it loaded on a flatbed just to get it to the shop.
The shops diagnosis now sounds more plauseable, but need to confirm why it would not crank yesterday.
 

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1999 SL600 | 2001 SL500 (sold)
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I did not get the specific codes, only what they meant per the mechanic. I do know oil levels were fine as there were less than 100 miles since the change.
You need to call and ask. Surely they would’ve noted the codes on some sort of paperwork, especially for the o2 sensor because there’s an upstream and a downstream sensor, otherwise rescan and let us know what they are. Also it sounds like you’re burning oil so even though you changed it recently you still need to pull the dipstick and physically check. Coolant should be looked at as well too. The level should be at where the white and black meet each other in the reservoir.

when did your car no long start? When you wanted to take it to the first place or after it got there?
 

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1999 500SL
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Discussion Starter · #13 ·
My mechanic buddy agrees the engine is shot. I am driving over there tomorrow to see if they will come down in price at all. Otherwise it's a 20k loss for me and I donate it to charity. It's not the coolant for sure. The oil was fine a week ago, not burning oil. The car drove fine a week ago, this just started two days ago. The replacement engine they have is 4k, then 3500 for labor. They are open to me finding a used engine for less cost but won't warranty it. If I chose to replace the engine I would sell it immediately.
 

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'96 SL 500
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93 Posts
If the engine is shot and a total loss I would still think you could sell the rest of the car for something to recover some costs. Some people like a 'project'. There's a guy on the forum putting a GM V8 engine into a R129 for example. Or someone may have a R129 that is mechanically fine, but may have had a bad rear-end collision. You could also part out the car (as much as you can be bothered to do) and recover costs that way.

Sometimes cars do just have a catastrophic failure, or you don't know what previous owners did or did not do. I read on your other posts that the car you bought sat a lot for the last few years, which could be an indication of an issue the previous owner did not want to face. But it also looks like it's in very good condition so some of those parts will be worth something. You have a tow hook cover, that's about $100 there or round about? ABS wheel sensors are quite valuable too.
 

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1999 SL600 | 2001 SL500 (sold)
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Sad to hear. The m113 is supposed to be the most reliable and durable engine Mercedes ever built. Guess you got unlucky and the engine randomly decided to die.

did your mechanic buddy confirm the hydrolock? And if so any idea how that managed to happen?
 

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R129 500 SL 1991
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1,710 Posts
...1999 SL500 with 67,000 miles on it... started smoking from the exhaust and is running rough...
one drip of what appears to be oil on the floor, but that's about it.
...
Revving the engine produces a little thicker whitish possibly blue smoke. I have had the oil changed six months ago using Mobil 1 European blend, but I have put less than 100 miles since the change.
... misfire fault in cylinders five thru eight, and another code was oxygen sensor also in five thru eight. They pulled all the spark plugs and found fuel in cylinder eight. They are telling me the engine is seized due to "hydro lock" and needs replaced.
The FIRST thing you should have been advised to do is to check your engine oil level before continuing to run the engine.

Overfilling the engine oil on an M113 is easy to do and can spell disaster for the engine. Especially the M113, which has two sump plugs, and the rear one can sometimes be missed by a mechanic not familiar with the M113, or a DIYer working under car ramps.

Get your mechanic or the shop to check the engine oil level. Also check the engine oil for fuel contamination.

Some M113 engines that have been overfilled have suffered severe engine damage due to excessive crankcase pressures and failure of both the front and rear main bearing seals allowing oil to flow into the torque converter and also onto the front drive pulley causing extensive collateral damage. The real damage occurs due to windage, as the crank counterweights pass through the oil in the sump, causing the oil to froth resulting in oil starvation, overheating and damage to the crank and camshaft journals and bearings. The oil that is thrown up into the cylinder bores places excessive pressure on the oil control and compression rings of the pistons resulting in severe damage to the pistons and the crank. Oil can also be ejected into the exhaust system coating the O2 sensors and cats in gunk. So the potential damage is not limited to the engine.

There is no such thing as a random M113 engine failure.

The oil drips on the floor are probably the main crank seals, probably the rear. You also noted the rough idling, smoking exhaust, after a recent oil change. My hunch is that the oil was overfilled.

I recommend that you get a competent shop who did not do the last oil service to check the oil, and also to confirm the extent of the damage. You may have a case against the shop who did your last oil change.
 

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R129 500 SL 1991
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also pull the O2 sensor to see if it is contaminated with engine oil.

I recommend that you get a thorough examination done to identify the cause of the engine failure.
 

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1999 SL600 | 2001 SL500 (sold)
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Check the oil level wit the car on a level surface with engine cold. Follow robms advice. It will only take you 30 seconds and can be the start of an actual resolution. If overfilled, document everything from that point onwards (pictures and notes)
 

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2000 SL500
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458 Posts
I'm curious about the hydrolocked engine and other diagnostics the shop did to confirm the engine needs to be replaced. If there was enough fuel in cylinder 8 to hydrolock the engine did the shop remove the fuel or sparkplugs in this cylinder and check if the engine will turn over? I'm wondering what damage was actually done to the engine, did they do a compression or leak-down test to confirm the engine was damaged? Even if there was enough fuel to hydrolock cylinder 8 when you tried to start the engine and it didn't turn over I'm not certain this will damage the engine, maybe the starter or flywheel but not the engine. I could be wrong but a compression or leak-down test would confirm if any damage was done.
You also mentioned your mechanic buddy also said the engine is shot; how did he determine this and what's is actually wrong with the engine?
There are more questions to ask the shop and your buddy as to what is damaged in your engine. Compression and/or leak down results, significant amount of water of fuel in the oil, coolant level low, endoscope photos, etc. What's the proof the engine is damaged to the point of needing replacement. Also, the cost of the engine and replacement cost quoted by the shop seems so far out of line I wouldn't trust this shop.
 

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1999 500SL
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Discussion Starter · #20 ·
I'm curious about the hydrolocked engine and other diagnostics the shop did to confirm the engine needs to be replaced. If there was enough fuel in cylinder 8 to hydrolock the engine did the shop remove the fuel or sparkplugs in this cylinder and check if the engine will turn over? I'm wondering what damage was actually done to the engine, did they do a compression or leak-down test to confirm the engine was damaged? Even if there was enough fuel to hydrolock cylinder 8 when you tried to start the engine and it didn't turn over I'm not certain this will damage the engine, maybe the starter or flywheel but not the engine. I could be wrong but a compression or leak-down test would confirm if any damage was done.
You also mentioned your mechanic buddy also said the engine is shot; how did he determine this and what's is actually wrong with the engine?
There are more questions to ask the shop and your buddy as to what is damaged in your engine. Compression and/or leak down results, significant amount of water of fuel in the oil, coolant level low, endoscope photos, etc. What's the proof the engine is damaged to the point of needing replacement. Also, the cost of the engine and replacement cost quoted by the shop seems so far out of line I wouldn't trust this shop.
All, I just got back from the shop. The engine failure was caused by a faulty injector. The oil levels were fine, coolant fine. He showed me the cylinder and it is definitely shot. It is the first R129 he has seen it happen on, just my luck. I have spoken to a few companies that sell used engines and there are plenty available for much less than what I was quoted. The owner himself agreed the 4K cost for the engine he was initially looking at was outrageous. He is more than willing to shop around for me to help locate one. I gave him the info I had found and he will call them, as well as a few other placed. He said that whatever engine we find, we'll take useable parts from mine to keep costs down. He said that we should be able to come in much less than what was initially quoted. I feel somewhat better at this point. Thanks all for your input.
 
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