My moms 89" 300 SEL has a vavle tran problem. Well last night when we went to Merrit Island to get a car. On the way there the oil was a little low(abut half way down). But we didn't realize it till we got there. Anyway, my mom promtly went to the local gas station in the area of the car we bought. Purchased some oil and was on our way home. This morning I checked and replaced all fiveplugs because somewhere between the time we got there and back. The car started running "wierd" almost like it was misfiring. I'm thinking "man I hope she didn't drop a vavle." Wich I'm positive she didn't becuase there's no sound of metal in the last cylinder. After replacing the old plugs with new ones here's what I saw, the #6 plug is cacked in oil. According to the plug diagram in my haynes manual it says oil depoisitis something about it either being slipping past the piston itself(rings) or vavle seating. I'm pretty sure it's vavle seating. Because it doesn't burn that much oil. But I did notice it goes low fairly quickly but not fast enough for it to be the piston rings.I checked the other 5 plugs as well. They where placed under "too hott" also caused by either poor valve management ,so far as fuel to air ratio in the cylinder or cooling. So in a way my moms car isn't having all that bad of a problem. Just annoying,however it's firing on 5 sounds like. The even more messed up thing is that when the car was originally purchased(few months ago). It needed a new head gasket,fine,no big deal was fixed and all. But the mechanic my mom had do the job claimed he went over the vavle tran and checked everything. Obviously not the case now that we are in this perdicament. The car always burned a little oil but went unnoticed because never showed so far as seeing it out of the muffler. You know like black smoke or nothing.So anyone have any suggestions along with a better mechanic in the Orlando area while we're at it?

~BB~

 

Hey, That sounds like the same problem that I'm having with my mercedes 300ce. It's would leak oil on the #1 spark plug and cause it to stall out on the road while driving. It would start up right away. A valve job up here in NYC is over 2500, which is not worth it for a 15yr. old car. So I'm thinking about steam cleaning the engine and trying one of those oil sealer on the market to see if that would make a difference. I agree with you that it's difficult to find a decent mercedes mechanic who knows what he's doing. I've spent $700.00 trying to fix a problem only to find out it was a $40.00 part that was defective all along. You might try calling the Mercedes service center in your area. Sometimes you can get a mechanic that will give you free advise over the phone. They don't mind so much here in the city since you'll have to wait three weeks to get an appointment to bring in your car for servicing.

Good Luck.
Audie

 

Just for hoots and eliminating the simple stuff first, check the resistance on your plug wires. Too many people believe in that 100K miles claim for platinum spark plugs. The wires and plugs can be original on very aged cars. I broke five wires on mine when I changed the plugs because they were so old and stuck in place. I don't know the exact resistance spec, but I would think anything above 5K ohms would be at least functional. Or, if there are any that are unusually low when compared to the rest, replace them.

 

Sounds like it is Valve guide seals. You didn't say how many miles you had but at about 100k theses engines are bad to let oil past the seals. Most any mechanic can do those for you but they should have been done with the head gasket job.