replacing valve stem seals on 300e

Hello,

My 300e is using about a quart of oil every 1,000 miles and may be fouling a plug or two in the process so I'm thinking about replacing the valve stem seals. Any advice on what to look out for while doing this job would be greatly appreciated. Found the following post on another site and dropped it in this post for comments on whether it sounds like a valid approach.

Also looking for a good quality valve spring compressor that will work on my particular engine. Saw this one on the Snap On site but have no idea whether it will work.

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Read another comment somewhere else which suggested that replacing valve stem seals was only viable on an older low mileage--implying that in higher mileage cars the guides tend to leak more oil than the seals. Any comments or experience with that?

Thanks,

Mike

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Hi

Changed the valve stem oil seals on my 190E about 2 years ago or more although it made little or no difference to oil consumption. Ayway here goes Remove HT leads from rocker cover Remove rocker cover Remove Spark plugs Remove oil spray bar Remove camshaft bearing covers/rockers The valves are all now visible and the engine can be turned over carefully with a socket on crank (not cam!!!)until the no. 1 piston is at TDC viewed through plug hole. Now this is where it gets scary Tap the spring of the 2 valves on no. 1 piston with a hammer and drift to break the seal on the collets. Use a valve spring compressor to squeeze the spring (the 1 i had was borrowed it was snap on great tool) and be very careful not to drop the collrts remove collets and spring . Valve will fall slightly onto top of piston remove oil seal and replace with new one lub it before fitting. Refit vave spring and collets. Repeat for second valve on no. 1 piston Turn engine over until no. 2 is at TDC and repeat. Repeat until all 8 valves are done. Reassemble using clean oil on bearings etc.

Points to note: Inlet and Exhaust seals are different. Do not turn engine over when valve springs are removed. Tapping the spring to release seal on collets you are using the piston to restrain the valve be sensible. Search and get the right tool for the spring compression make one is possible. Make sure the piston you are removing the springs on is at TDC if it is not the valve could fall into the chamber!!!!!!!! Do not puncture rad with socket on crank bolt.

Good luck

This was over 2 yrs ago

230K
Reply to
mharness
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If you asked a car manufacturer to do this job under warranty they would refuse claiming the oil consumption falls within "normal" parameters.

Suggest you install the next higher heat range spark plug and first see how they perform.

One can always pull the engine apart, the idea is to avoid doing that for as long as possible.

Reply to
T.G. Lambach

This is a weekend job provided you have the right tools & are fairly confident in your wrenching abilities. However, before you do this you might want to switch to Valvoline MaxLife oil (or a mix - I use 3 qrts Mobil 1 15-50 plus 3 qrts 5-30) which will swell the oil seals & the valve stem seals. I replaced the valve stem seals at 70K miles on my 92 300e as it was using about a quart per 1K miles. Oil usage started creeping up again at around 110K miles, so I started using the Mobil/MaxLife mix. At 130K miles it now uses a quart every

5K miles.

If you do decide to change the seals, couple of things you worth considering: Buy a couple of spare collets before you start the job. If one bounces out while you're compressing a valve spring & disappears down the side of the engine you will not be able to find it... trust me. Before moving a piston to TDC to remove the valve spring, feed in a length of nylon rope. When you move the piston up the rope will now push against the valves & prevent any drop. Only turn the engine in it's normal running direction, clockwise. Turning it the other way can cause the cam chain to skip teeth & you do not want that. Put the hood in the fully vertical position. Makes getting to the rear of the engine much easier. As for the valve spring compressor, I used a generic one. Just been out to the garage to check, there's no manufacturer name on it that I can see. I found it by doing a search for valve spring compressor on Google. Progressive sells an expensive one specifically for 124 engines.

Think that's it, good luck.

Chris

Reply to
CRGILL

Don't mix oil grades!

Reply to
Martin Joseph

This is probably a troll, but why on earth not? They mix together perfectly well, & it's what oil companies do all the time to produce their various grades plus semi-synthetics (mix of synthetic & dino oils).

Reply to
CRGILL

Why? That's how oil is made, mixing different oils together.

Reply to
Richard Sexton

Thanks for the good advice.

Mike

Reply to
mharness

for the tool try ebay under mercedes tools, i see valve spring compressing tools from time to time

Reply to
LetsTalkLegal

I guess you are all petro chemists then huh?

I hear chain saw oil works real well also, mix some of that in there...

:~)

Reply to
Martin Joseph

Is there any reason that you know of why this spring compressor won't work?

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I'm wondering if there's enough room between or around the tool and the valve stem to break the keeper loose without jeopordizing the valve.

Thanks,

Mike

Reply to
mharness

If I remember rightly, that tool will not work as it's not possible to get the lower tangs under the spring.

You need a tool that looks like this one, which hooks under the camshaft & push down on the lever.

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This one looks like it might do the job too & is cheaper. But don't take my word for it, do some checking yourself.

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Chris

Reply to
CRGILL

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