I have 1989 560 SL mercedes and there is no compression on drivers side. Also chain guide broke and chain loose does this mean that a valve job needed

Nissan maxima does have a chain and if the cover has broken it will be an expensive repair
items of concern are the chain, the cover, the sprockets for the cams and crank, the adjuster and the guide and valves ( it is not listed as an intereference engine but prudence suggests to expect bent valves)
I seriously suggest that you by pass the local garage and seek assistance form an accredited service shop that has experience in your make of vehicle as it is not a simple change the chain job.
get quotes first as the expenses can be double because of the extra damage incurred

if your loosing compression it could be dirty valve guides or valves. could also be poor rings or a loose timing chain. have the compression checked when its happening.

get it to a auto repairer right away and get it fixed it is crusiel.

Hi Sarah, It would seem to me that either the tensioner or a bolt has come loose on the timing assembly. Unfortunately if something like that happens and the chain jumps, the valves would loose synchronization with the crankshaft and pistons, meaning there could have been collision between them, thereby causing damage to the valves and possibly to the pistons. To solve the problem will mean dismantling and checking the timing mark alignment against the relevant match marks. I am suspecting that you will find that they no longer align and will need realignment. (meaning you'll need to do the previous job over) and when completed carry out a compression test. If after assembly and carrying out that test the compression is very low, the valves will probably have been bent. You will need to remove the cylinder head and carry out rehabilitation. Unfortunately the only way to inspect piston, con-rod and crankshaft damage is a complete dismantling. Regards John

I'm 99% positive that compression should be more than 200psi. If the chain broke it bent valves. A used motor would be your better option. The 1.9 SOHC is a cheap and common engine. The 1.9 DOHC will be considerably more expensive.

If you have a manual transmission the engine and trans will need to be pulled together and separated out of the car. If you have an automatic transmission the engine can be removed without pulling the transmission.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

replace the guides and tensioner . recommend a new chain also

Timing Chain & Gears Removal & Installation To Remove:
NOTE: Keep the cam chain away from magnetic fields.
Crankshaft set at TDC marks

1. Turn the crankshaft pulley so its Top Dead Center (TDC) mark (1) lines up with the pointer (2).
2. Raise and support the vehicle.
3. Remove the front tires/wheels. Front undercar splash shield
   
   
4. Remove the front undercar splash shield.
5. Remove the drive belt.
6. Remove the cylinder head cover (See section on Valve Cover).
7. Remove the crankshaft pulley (See section on Crankshaft Damper). CKP sensor and VTC solenoid electrical connectors
   
   
8. Disconnect the Crankshaft Position (CKP) sensor connector (1) and Variable Valve Timing Control (VTC) oil control solenoid valve connector (2).
9. Remove the VTC oil control solenoid valve (See section on VTC Solenoid Valve).
10. Support the engine with a jack and wood block under the oil pan. Ground cable and upper bracket removal
    
    
11. Remove the ground cable (1), and remove the upper bracket (2). Side engine mount bracket removal
    
    
12. Remove the side engine mount bracket. Timing chain cover removal
    
    
13. Remove the timing chain cover bolts both from the front to the block and from the bottom to the oil pan.
14. Remove the timing chain cover.
15. Loosely install the crankshaft pulley. Compress the timing chain auto-tensioner
    
    
16. Turn the crankshaft counterclockwise to compress the auto-tensioner. Lock the timing chain auto-tensioner
    
    
17. Align the holes on the lock (1) and the auto tensioner (2), and then insert a 0.06 inch (1.5 mm) diameter pin (3) into the holes.
18. Turn the crankshaft clockwise to secure the pin. Removal of the timing chain auto-tensioner
    
    
19. Remove the auto-tensioner. Removal of the timing chain guide B
    
    
20. Remove the cam chain guide B. Removal of the timing chain guide A
    
    
21. Remove the cam chain guide A (1) and tensioner arm (2).
22. Remove the cam chain.

chances are you smacked a valve when it broke so it is going to require the removal of the cylinder head and a proper valve job performed. these kinds of repairs are better left to professionals due to the fact if you dont get the right torque it will not work, or turn the engine left while the chain is attatched you stand to bend valves again.

First, the timing chain runs from the crank around the gears on both cylinder heads. There may be 2 chains. What it does is keep the closing and opening of the valves "in time" with the compression and exhaust stroke of the combustion chamber (pistons).
No compression on the entire left side is not good. If right side is okay then you have 2 chains one for each side. Left side chain must be broke or damaged.
To check the compression without using air , someone had to turn the crank over. If this was done with a bad or broke chain you may have bent valve(s) as well meaning cylinder head rebuilding or replacement.
If you plan on keeping the car for a while consider replacing or rebuilding the engine.

It is probably not the timing chain but the tensioner and guides. The guides are some bakelite plastic ****. you need to take off a lot stuff, belts power steering, altenator pulleys timing case cover. Check the timing gears and chain for damage. Replace guides tensioner and any damaged parts. Disconnecting the front motor mounts you have raise and lower the front of engine with a hoist to gain access to the timing case. A long tedious job and hopefully your valves weren't damaged when the chain let loose if so the whole thing is just not worth it
terry the pirate