Thanks. Well, it was running a little poorly last winter, but as temperatures went into the 60s and 70s for lows, it was fine. I would not have to let it warm up at all. Now that it is cooling again, not only is it doing what it was last winter, its worse- so whatever it is - is getting worse. Sometimes even after it warms up and it shifts into higher gears and the RPMS lower, it will miss for about a second, then smooths back out. Whats strange now is that my stalling problem has seemed to subside- at least for now.

I still have to check for air leaks. I have been so swamped, I have not had a chance. I will probably check it Sunday afternoon. Something has got to be done! Maybe you are right, maybe I should sell it before the timing chain snaps, rail break, or even the tensioner. Lord only knows when/if they were changed.

Or why not just change the chain and guides? Not an impossible job, and parts would certainly run you far less than the upfront investment in another car, along with a new set of problems you might possibly inherit. I bet if you pumped $1000 into that car and devoted 2 or 3 weekends to repairing it, it would run like new and would be good for another 50,000 miles.

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

I would change them, but the engine has a faint knocking sound between 1600-1900 rpms. It has not gotten any worse in the 10K miles I have owned it, but I am concerned that my engine is simply worn out and really do not want to put $$$$ into the engine if it is knocking anyway. I have been told that the knock could be a worn camshaft on the passenger side of the engine.

Transmission wise, body wise and interior wise, I know this car would easily last another 100K. Body rust free, interior in excellent conditions and everything still works (save for the A/C).

Thanks - you are right- I probably should sell it. I would like to see a MB fan and a DIY'er to buy it- replace the chains, etc and find out whatever is causing the rough cold idle/hot stalling.

to update, I was told by the mechanic that replaced my PS seal that noise was probably just the lifters too- so not to worry too much.

I asked him about the poor running engine when cold. He is a Volvo tech, and he admitted that he was not that familiar with Mercedes, but he suggested that it may be some sort of sensor that was thinking that the engine was hot, when it was cold and visa-versa. He listened around for vacuum leaks and did not hear any he said.

So, here are the updated details- some things have changed.
When it is cooler outside- when I first start it in the mornings- it runs smoothly, until I press the accelerator after it is running- then it will start to "stutter" and chug alittle. Like its misfiring. There were occasions when it did that, that it was putting out a gassy smelling smell out of the exhaust. I let it run for a bit and it clears out- then I take off. Then it will miss only for a second after it shifts into the next gear, when it goes to a lower RPM- then it clears out until it shifts to the next gear- then clears out after a second. Also- I have noticed- that when in gear- it idles smoothly after the engine warms up, but when in park or neutral, it misses (shakes). I have installed new plugs, but not plug wires. Could this possibly be the culprit? They look original, but still in good appearance condition, but I know that could mean little. However, I do not think that would cause the stalling the in the summer when the engine is hot.

Another thing- about the engine temperatures. When the temps are cooler, the temp gauge rarely goes above 85°C and when on the road- it goes down to about 60°. When it is hot outside- when in town - stop and go driving, the gauge goes to about 120°C, but when I get back on the highway or freeway, it goes back down to about 90°C. I think a thermostat may be in order? Also, I KNOW for a fact that the power auxillary fan is on the fritz. It has never worked and when I install a new fuse, it instantly pops, so something obviously not right. I tried disconnecting like someone suggested to see if it still blew a fuse, but I cannot get it disconnected.

I have already bought a newer truck, but still like to use the MB as a daily driver, which I am still doing. I just chug along until it warms up. I may still sell it yet to someone that has the time, money and know how to give it the attention it needs.

I am wondering if the thermostat, or a sensor of some sort may be causing some of the problems, rather than a vacuum leak? Whether I sell it or not, I would like to get it running smoothly again.

Thanks again!

The thermostat should keep the car at about 90c minimum. If you're seeing the temp cool down to 60c while driving, likely there's no thermostat at all, or the one you have is stuck open. No thermostat will also cause the coolant to circulate too quickly, which can cause overheating - the coolant must spend the appropriate amount of time in the radiator to allow the heat it contains to be removed.

One way to check for a missing/stuck open thermostat is to start the car when it's cold. Have the hood up when you start the car to keep the underhood temps from climbing too quickly. Wait a few minutes - maybe 5 at most, and touch the upper radiator hose about mid-way between where it connects to the radiator and where it attaches to the thermostat housing. BE CAREFUL of moving parts, as this must be done while the motor is running. The hose should be at or near ambient temperature. The hose should remain relatively cool to the touch until the thermostat opens, at which point the temperature of the hose will change rather quickly. If it gets warmer very gradually, then likely the 'stat is stuck, or is missing entirely.

Since your A/C is out and the aux fan is not running, you will likely see increased temperatures in traffic in warmer weather, but I'd think that the engine fan, if the viscous clutch is working properly, should be able to keep you out of the 120c range - other's may have different ideas here, I'm still learning about my Benz. I've read several posts that talk about the "rag test". I assume this to mean that if the clutch is operating properly, when it's fully engaged (I'd guess at about 100c on the temp gauge), a rag, when placed across the shroud of the electric fans, should be held in place by the airflow. Others suggest that a fully engaged clutch will cause the fan to stop spinning almost immediately after turning the engine off.

I'd check/replace the thermostat. The work is fairly easy and the parts aren't that expensive. Modern cars MUST have a properly functioning thermostat to run properly. Just be sure to follow the instructions carefully on replacing the 'stat on your car. I missed one little line in the instructions when changing mine and had a devil of a time getting the air out of the system.

In your first post you said the engine smoked after starting! Is it black smoke or blue/white smoke?
Black smoke would indicate the mixture is too rich (check the vacuum lines to the warm-up regulator)
Blue/white smoke would indicate worn out valve guides (oil fouled plugs will cause an engine to run badly till they clean up.)
Mike

Thanks for the replies guys. I think the thermostat may be part of the problem.... I will replace it posthaste.

Mike- it only did the smoking a couple of times and yes, its a black smoke... it was "chugging" when it was doing this. BTW- where is the "warm-up regulators" on these cars? I have never heard of them.

I have never seen any blue smoke from this car. Despite nearly 269K miles, it does not have any oil smoke, nor does it leak or burn any oil between changes. Amazing I know.

Thanks again.

86, do as the man says, either put a little money into it now and bring it up to a car that won't have you worrying, or get rid of it and buy something else.

If you are going to be doing some travelling for work, you need to make it worry free - DO THE RAILS, CHAIN AND TENSIONER.

You current issue sounds very much like a stuffed t/stat and they are as easy to fix as they are on Fords/GMs.

Cheers

__________________
1988 W126 420 SE

beware of fundamentalists!

Thanks. I probably will change that *IF* I get the engine lifter noise / knock (between 1500-1900 rpms) to subside and if I can get this missing problem to subside. I am planning on trying that "auto-rx" internal engine cleaner upon a few folks recommendations to see if that will reduce the engine ticks/knock. It may be my oil tubes are clogged or something, or maybe the camshaft on the passenger side is too far gone. I just hate to put $500+ into an engine and still have knocks and lifter noise, ya know? Not to mention $$ for plug wires if the engine miss continues.

I have a 2000 Toyota that I *could* use for this work travel, but it is a 4wd, V8 truck and MPG's is not that grand and I really do not want to put wear and tear on it, as it still has relatively low miles. It was rumored that I would be getting a company car (2005 Impala) for use, but I have not been officially told that. If I do not get the car up to standards, do not get a company car, I may just tell them that I cannot do it.

Thanks for the info in the t-stat. I was told it could be part of my poor running problems, as its giving the computer a false engine temperature reading or something. Good to hear its easy to change.