New valve stem seals--now a miss? - PeachParts Mercedes-Benz Forum

lee polowczuk · #1 12-09-2007, 09:13 PM

I am going to try this another way...

I replaced the valve stem seals in the CE yesterday... now it seems like I have a miss.

Is it possible that I could have not seated a new seal properly...and its causing the roughness.

I thought at first it was a vacuum issue...but i can't find any vacuum lines that are disconnected.

Car was running perfectly prior to the changeover.

If i pull the wires one at a time.. no change..

I may have to pull the valve cover again..and the rockers to see if I see anything amiss... I really don't want to pull the springs again

mbshop · #2 12-10-2007, 02:52 AM

really need to find what is causing the miss. lack of fuel? lack of spark? lack of compression?

t walgamuth · #3 12-10-2007, 07:31 AM

It should be not related to the valve seal job directly. If pulling spark plug wires does not make it miss, it must be a vac issue....or perhaps a fuel issue which seems unlikely.

Tom W

lee polowczuk · #4 12-10-2007, 08:57 AM

yes, i was stumped a bit after pulling each wire.... pulling one by one, it got worse obviously. i was hoping i would pull one and it would stay the same, thereby identifying the culprit.

i will fiddle again as the week goes on..... i may change out the wires completely with those that are on the 260e....

I did change out one vacuum line....but it was a new clear hose...

t walgamuth · #5 12-10-2007, 09:42 AM

When does it miss?

Tom W

lee polowczuk · #6 12-10-2007, 11:15 AM

you start it up and it runs, but the idle is slightly rough..

Drive it and you can tell there is a miss..especially when you try to accelerate hard. At speed it seems to run fine, but as you slow down you feel the miss again.

I put a stethoscope on various places over the valve cover and i don't hear anything unusual. When i pulled the plug wires individually, they were all creating spark... i don't know if that means anything, however

I may have mentioned that I did the valve stem seals on our 260e over Thanksgiving and that operation went well.

lee polowczuk · #7 12-15-2007, 03:16 PM

well.... i loosened each fuel line...and it seems like the culprit is cylinder 3.

I changed the number three wire from the 260e... no difference.

pulled the valve cover... everything LOOKS normal.

Is it possible the cause for the miss is a valve stem seal that is not seated properly? I did pull the spark plug from that cylinder and it was clean.. I think i will pull the others and take a look... of course the car has only been run a couple of miles since the stem seal change

I probably should have changed out a spark plug first...but the ones in there are the non-resistor bosch's that i just put in in the spring.

t walgamuth · #8 12-15-2007, 03:51 PM

The plug still could be bad and look good, so try changing that. Then I would suspect the injector.

Tom W

lee polowczuk · #9 12-15-2007, 03:56 PM

well, i will probably change the plug..

the car was running perfect and has run perfect. I did the valve stem seals because it was going through a quart of oil at 650-700 miles.

Don't know why a miss would occur after the job. I really thought i damaged a wire when pulling them.

EDIT: all plugs are dry

On Sunday I am going to pull a couple of springs off and take a look at some seals.. i am a bit stumped

lee polowczuk · #10 12-20-2007, 02:30 PM

Go figure. It was the plug.... i switched one out from the 260E... and all is well.

I then went to the dealer and much to my surprise they had them in stock.

$3.32 and problem solved

Thanks all.

Now I am hoping the valve stem seal job will cut down on some of the oil issues I had, especially with the aging 260E

Texholdem · #11 12-20-2007, 03:53 PM

Quote:

Originally Posted by lee polowczuk

Go figure. It was the plug.... i switched one out from the 260E... and all is well.

Now I am hoping the valve stem seal job will cut down on some of the oil issues I had, especially with the aging 260E

Hi lee,

I have followed with great interest your thread. How can one determine that the oil leak comes from valve stem seal? In other threads people say it could be also timing cover seal or head gasket seal?

I am using 1 quart per 1200 miles. A shop suggested an oil leak detection for $69. Is it reasonable to have it done instead of guessing around?

Thanks!

lee polowczuk · #12 12-20-2007, 04:02 PM

I think it's well documented that valve stem seals need to be changed at the type of mileage I have on my cars.

When you have bad valve stem seals, the oil doesn't leak.. it leaks down into the cylinder and burns off.

I have some minor leaks in my car, too... i guess i just live with them.

My valve cover gasket was close to being petrified...

A quart every 1200 miles isnt' bad... my 260e was going through a quart at 400... the CE was going through a quart at 650-700 at 164k. At 142k it was going through a quart at 1200 miles

Texholdem · #13 12-20-2007, 04:23 PM

Hi Lee,

thanks for the prompt reply. I have the same 1989 300CE and it is at 97K now, I guess it is also time to do the valve stem seal job (or to get it done because of my two left hands

).

lee polowczuk · #14 12-20-2007, 05:02 PM

the valve stem job wasn't hard... it did take me more than a year to get the guts to do it...

i was terrified that a valve might drop down into the head if I didn't get the engine to TDC correctly.

Anyway... i "practiced" on the 260E... it took 6-7 hours including breaks....

the CE still took me 6 hours.... some of that has to do with the cheap 10 dollar spring compressor that you buy or borrow... but most of all it just takes that type of time...

anyway... good luck....

donbryce · #15 12-20-2007, 10:00 PM

OK, I'll bite....what was the problem with the plug, and how did you finally isolate it? I thought you had only gone a few miles after the seal job, so did this short distance foul the plug up, or was there something totally unrelated to the seal that was wrong with it?