1997 SL500 died, sell for parts?

[jsap]

My 1997 SL500 looks like it might need a valve job. I've been hearing tapping noises for a while now, and used Techron to try to fix it, but instead, the car lost a cylinder and the check engine light came on. The exhaust smelled like burnt oil. When I went home, all the spark plugs had normal fouling, but one was all gray (including the ceramic nose). I turned the car on with the plug out, and the sound from the engine was like somebody was smacking the engine block with a wrench.

Does anyone know if this is a valve job? How much am I looking at?

Also, what would this car be worth if I try to sell it for parts? I live in Marin County, California.

Thank you in advance,
John

[junqueyardjim]

No need to start an engine with a plug out. That just makes a lot of noise, if it will start at all. It does sound like your engine needs work. Just what it needs would need to be checked out more throughly then short description of it that you have included in the post.. Parting out a vehicle is usually not a fun way of getting rid of it or getting what it is worth for it. It is a pretty desirable car, a 92 500 SL. But if it is hardly running, then you can't expect too much either. How much will it cost to do the heads? My guess is that if you farm it all out, probably $4000.00 to 5000.00. Compare that to what you think the car is worth. If you part it out and your engine is junk you won't get anything for it either. I would suggest repairing it correctly or disposing of it in one piece to the P & P type junk yard.

[abiby]

From your description, I couldn't even begin to guess....

IMO you should break down and take it to someone knowledgable enough about that engine to make a good diagnostic of what's wrong and what would be needed to repair it.

Good luck.

[jsap]

With advice that I should have this checked out, I took it to an indy who did a compression test. He refused to do both dry and wet, so I only have dry numbers: 135 on #2, and the rest 145-150.

Is a dry number of 135 a definite evidence that the cylinder is ok? Or would a wet test provide that assurance?

I'm asking because the mechanic told me that he won't do a wet test because it means nothing, and that I've been reading too many weekend warrior websites. But, his assistant (who actually did the work) told me later that he didn't do a wet test because he was afraid that he might blow up the engine if he did. What the hell? I paid $240 for this ambiguous info! And he was only authorized for $120 to begin with....

To boot, I took the car in with 1 bad cylinder, and when I took the car back, it had two bad cylinders. He said I should replace all my plugs (only ~12,000 miles on them) to Bosch (I have NGK BCP5ES), all my plug connectors, and two coils.

The funny thing about this is that he said the #2 & #8 coils have to be replaced. But, I tested the car with just 4 cylinders (1,4,5,8) with the firing order 1-5-4-8-6-3-7-2. That means the engine was running 1-5-4-8-X-X-X-X, and it ran like that fine. If it were true that #8 was bad, that means I actually ran 1-5-4-X-X-X-X-X, and I seriously doubt the engine would have done that.

So, when I picked up the car, the car ran worse than ever. Before, the car shook like 7 cylinders. Now, with #8 gone after the mechanic touched it, the thing ran like the wheels were square. And at idle, the car shook violently like it was a gangster car on hydraulics.

Well, I'm pretty disappointed with this mechanic (a Mercedes Certified Factory Trained blah blah blah), but those dry numbers are all I have to go on.

If I had an OBD II reader, I could swap the coils and find the misfire codes jumping around as I move the coils. Without that, my method was to run the car at 1,4,5,8 and place the #2 coil/plug/connector in for #1 and see if there was any difference. There was none, so I'm skeptical that it's a coil/plug/connector issue.

What would you do? I'm thinking about changing the plugs first, then connectors, then coils....

[junqueyardjim]

I'd suggest selling it and getting a driver maybe a bit less sporty, but more serviceable, easier to maintain it yourself and costing a lot less money to maintain.If your auto really ran worse after the test, you might be experiencing a failure of the main engine wiring harness. Your model year indicates your car is right in the middle of that "green" biodegradable wiring. That might be the first place to start, the harness runs $1500.00 to $2000.00 plus installation.

[dstorey]

135 psi is not low enough to cause the type of problems that you describe. Was the test done with the engine cold or hot? Anyway, If I were you I would go to pep boys or some shop that can read the obd codes for you. There is a new fletchers by me that has some pretty good stuff. The tapping you describe could be anything. Junqueyardjim may be on to someting because the harness is always suspect in these years, and a compression test will certainly disturb the wiring to the coils. On your car each cyl has its own coil and short connector to the plug either of which could not like rough treatment

[ctaylor738]

The engines have plastic "bridge" tubes that move oil from one set of valve actuators to the other. They are heat-sealed on one side and the seal blows out, with the result that one hydraulic actuator doesn't get oil. A very common 119 problem. Sounds like you have this issue along with a couple of bad coil packs.

You can get an OBD reader for almost nothing to tell you which cylinders are misfiring. It is probably the coil packs or the shop screwed up the wiring when they removed them for the compression check.

The replacement bridges are about $12 each, and you need 16, along with the plastic chain guides. I did a post in the Tech section awhile ago about how to replace them. It's a lot of wrenching, but not very complicated.

[jsap]

Well, thanks everyone for replying. Here's an update: when I picked up the car, the mechanic screwed me.

When I took the car in to him, I was on 7 cylinders. I had checked all of the sparkies, coils & connectors, and all were firing. After having my car for half a day, he told me on the phone that the repair would cost $720 to fix 2 coils, 8 spark plugs, and 8 connectors, and the cost of the diagnosis would not be credited toward the reapir. Because I brought the car in only for a diagnosis (this was pre-arranged with him), I told him I'll fix it myself.

But, he charged me $240 (twice the original estimate), and when I picked up the car, it was on 5 cylinders. I brought the car home (barely running), I tested the sparkies, coils, and connectors, and 3 coils were out. Worst of all, he said that #2 & #8 were out, but it was #3, #6 & #7.

My diagnosis? This mechanic is bad seed. He tried to gouge me on repair work at $720 + $240 (what greedy mechanic wouldn't apply the diagnosis fee to the reapir?), but the $720 is about half labor. He's already got the car opened, so all he has to do is pop in $360 worth of parts (at retail price) and close it up. That's worth about 1 hours. So, he's trying to charge me $360 per hour, on top of the $240 he charged for 2 hours of bulls**t diagnosis. And, he sabatoged or stole 3 good coils. I called the young lone assistant at the shop, and the kid said "This isn't worth my job, and I could get in big trouble for this, so I'm not going to talk about this, okay?"

Anyway, after getting 3 new coils, I put all my old stuff back. This time, I cleaned all electrical contacts and used a dash of dielectric grease. When I turned the car on, everything was fine.

My guess is that I just needed to clean and grease the contacts.

As for the ticking, I dug under the valve cover, and I had a plug missing from the cam oiler tube. I replaced it, but the ticking remains even after a long hard drive.

I have three theories:

1) The timing chain had a bit of play. When I press on the chaing (with the plastic guide off), the links moved around a bit. Is this normal? I recall tightening the tensioned on my motorcycle before, and the timing chain was taught like a rubber band.

2) The haudraulic lifter is sludgy. I'm thinking about doing what others have done: motor flush, and then Marvell Mystery Oil.

3) The haudraulic lifter is crushed. This is the worst case scenario. When looking at the lifter surface and the cam lobe, though, I don't see any abnormal wear.

I'll update again.

[ctaylor738]

Sorry you got screwed by the mechanic, but things seem to be looking up.

Are you sure that you don't have another open tube?

You could have a collapsed lifter/actuator or your chain tensioner might be weak. The chain should be tight.

I recall that the procedure to check the chain stretch is way more involved than replacing the chain BUT I once asked two major online parts places if they sold a lot of 119 chains. One said "no" and one said "never."

[alabbasi]

If you have a 1997, invest in an OBDII reader for $100, it will save you a lot of time in tracking down problems.

[jsap]

Originally Posted by ctaylor738

Sorry you got screwed by the mechanic, but things seem to be looking up.

Are you sure that you don't have another open tube?

You could have a collapsed lifter/actuator or your chain tensioner might be weak. The chain should be tight.

I recall that the procedure to check the chain stretch is way more involved than replacing the chain BUT I once asked two major online parts places if they sold a lot of 119 chains. One said "no" and one said "never."

I just checked under the cover, and the tubes plugs are all intact.

A stretched chain is a possibility, but from the sound of it (see youtube video below), it definitely seems to be a single lifter. I've calc'd that at 700 RPM, there should be 5.833 ticks per second: 700 / 60 / 2. The "2" is for two crankshaft rotations per one camshaft rotation. Because the sound on the video is about spot on (it's about 600 to 700 RPM), and because the sound comes from somewhere back toward cylinder #3, I'm pretty sure it's a lifter.

One of these days, though, I would like to check the timing chain stretch. It's a comfort to here from a trusted mechanic I know that he's never had to do that work before on an M119 because he's never bad to....