How fast can a valve seal fail? - PeachParts Mercedes-Benz Forum

Blue 72 250 · #1 02-10-2007, 06:59 PM

I am wondering how fast a valve seal can fail on a 72 m130v with 96,000 mi.

I had her running great the last few weeks, an I even cleaned out the fuel tank last week. But in the last two days the #1 cyl. started to miss on startup but would go away after about 30seconds of running. Yesterday it began blowing blue smoke and the plug is covered in oil this morning.

I did a pressure check and it is 150psi - I am thinking that one of the oil seals failed.... but is seems so dramatic of a failure considering that she never burned any oil in the past.

What do you guys think?

cth350 · #2 02-11-2007, 08:27 AM

that or you have a bad guide. Or there's a head gasket seal problem to an oil passage. Leakdown test is next.

-CTH

Blue 72 250 · #3 02-11-2007, 01:09 PM

I do not have the proper tool to do the leak down test. If I pull the head before the test is it possible to know if the guide is bad based upon visual inspection? I assume the seals would all be changed given the cost is low.

I am going to proceed under the assumption that the head is coming off either way. I guess that I will be able to address other things at the same time like the chain and rails. Any other items that I should be thinking of at the same time?

What do you think about pulling the head as an assembly with the cam and towers still attached and taking it to the local indy Benz guy? I figure that I can save a lot of labor getting it off, but my tools and skills are limited after that point. He can do the valve job and reassemble the valve train. Is that even possible?

Thanks

Arthur Dalton · #4 02-11-2007, 01:23 PM

I see M130 where the valve seals pop off the stem seat..might want to look at that before you condemn the head/guides. etc...

You can also do seals without removal of the head.. the new seals are of a bettter design and fit.

Chas H · #5 02-11-2007, 01:45 PM

I have seen the valve guide come loose in the head.

Blue 72 250 · #6 02-11-2007, 02:43 PM

Thanks for the input.

So to check the valve seals I would remove rocker and compress the valve spring right?

The manual that I have only describes the removal of the head and I am not sure of the procedure. Please advise.

#7 02-12-2007, 01:50 AM

Quote:

Originally Posted by Chas H

I have seen the valve guide come loose in the head.

Yup, and that will trash a head in short order.

I used a vacuum guage to help diagnose the problem, the guage needle fluttered violently, on the 190SL. It didn't smoke a bit, but it had a very odd misfire.

Chas H · #8 02-11-2007, 04:08 PM

You can check them visually without removing the rockers. Just compare the position of the seals. If one -or more- have popped off, it should be apparent.
Getting down to the seal to remove it requires supporting the valves with compressed air so they don't fall into the cylinder when the keepers are removed. If you only do the intakes, you might get by without the air, but the piston will need to be at exactly the top. I have always used compressed air because I have always changed both intake and exhaust seals.

Blue 72 250 · #9 02-11-2007, 04:21 PM

I checked out the DIY link and the job looks like a "fun one".

I am planning on doing all of the seals, Intake and Exhaust. Why go to the effort without doing all of them.

So I also figure that if the guide failed that I would not be able to remove it with the head in place. I will keep posting as questions ome up.

t walgamuth · #10 02-11-2007, 04:26 PM

you are correct about needing the head off to do the guide.

if it were me i would do some more diagnostics before tearing into it.

now you will ask what but i am at a loss to say exaclty what.

leak down i suppose.

tom w

Arthur Dalton · #11 02-11-2007, 04:28 PM

You can make a spring removal tool out of a piece of square tubing. It has a cut-out on the end to slip over the ball stud and a cut-out in the center to allow access to remove the spring lock keys. Real simple and works great if one is just doing seals with the head still on.
I will see if I can list the dimensions... or.....just get a Hayne Manual and they have a picture of one and how to make it...
I use a magnet to grab the keepers.
Make sure you get the new style seals.

Blue 72 250 · #12 02-11-2007, 05:05 PM

I have the Heynes manual and have seen the valve spring tool.

I assume that the new style seals is the kit that has teflon and Rubber. Does the teflon go on the exhaust valve and the rubber on the intake?

I am debating the leakdown test because I dont have the proper tool to do it. Should I spring for the tool? Will I get a definitive diagnosis? I may be able to get my local indy to loan me the tool, but you know how that goes.

I am going to go out to the garage and pull the cover to see if I can see slipped seals. I am hoping that is the problem. I just can't believe how quickly I went from clean burning and nice looking plugs to lots of oil in the #1. There has not been any overheating problems for the car, and the oil and coolant look great. I would be shocked if the head gasket failed. The weather has been cold.... but not that bad. I dont take her out when the temp is below 20F.

Blue 72 250 · #13 02-11-2007, 05:50 PM

I pulled the cover and did not see any obvious slipage of valve seals. They could have slipped and I would not be able to tell given the springs in the way.

I made a few other interesting observations that I want to ask advice about.

1. The timing chain has a master link on it. Did the origional build on the m130 come with a master link? or was the chain one piece? The only Reason That I ask is because it may indicate the milage on the car is a higher then I thought.

2. I have always had some "weaping" of coolant coming from the head back by the #5. When I got the car my local mechanic "Rudys star service" in Fort Collins Colorado, a trusted and loved source of guidance told me that I should not worry to much about it. He said that the M130 could weap for years and not indicate any major problem. The problem has not gotten any worse and the weaping is far from the #1 where the oil is a problem.

I assume the answer is do a leak down test.

t walgamuth · #14 02-11-2007, 05:58 PM

it seems it would be a lot easier than pulling the head to investigate.

beg borrow or steal.

tom w

just kidding about stealing.

Arthur Dalton · #15 02-11-2007, 05:59 PM

Master simply means the chain has been changed..Normal preventive maint on a 130 at about 75-100K

Leak test will not tell you seals are bad , but will test the rings in that jug. You can do the same by simply making an adapter from an old plug and brazing an air chuck on it and hooking it to some air from a source. Then listen for crankcase blowby.

At that milage . seals are due.
It is also comon practice to retorque the head on these engines. We routinely do that when adjusting the valves, so you may be able to get rid of the weeping with a simple head retorque procedure....