Gary C

It is time to do my valve cover gaskets. The dealer wants 6.6 hrs labor at 100 bucks per hr. So I am going to do this myself. They quoted 32 bucks per side for the gaskets. I see them online for half that. But I read that the aftermarket ones are not good. Where do you get Genuine gaskets for 16 bucks or so?Also the parts guy told me that they usually change out the vacume hoses because they are usually dry from heat and break. Where do you get those cheaper than the 40 bucks he quoted me for 2 hoses? And last he said the oil cap gasket at 15 bucks. Where to get that? Also it seems like there are 2 parts to the valve cover. The top part seems to be leaking too. Under the fill cap. This is sealed with silicone? What kind? anything special? This is a CLK 500 anybody have the whole process with pictures?

Rudeney

Yes, use genuine MBZ gaskets - the popular Victor Reinz aftermarket gaskets are made to thin and won't seal. The breather covers use RTV silicone instead of a pre-formed gasket. There is an approved MBZ part, but I'd just use a good black RTV (colors are usually based on heat resistance - you want black). Do not use any sealant on the gaskets. And yes, you probably will need new breather hoses. I believe the filler uses RTV where it bolts to the valve cover, and a rubber gasket under the cap.

This is a very easy job. 6.6 hours is nuts! Book rate is 41 WU's at 5 minutes each = 3:45. This should include all work, cleanup, etc. If there's not a DIY here, check the W203 or W211 forums. If you find one for a C/E320 or C240, it's going to be the same for your CLK500 - your M113 engine is identical to the M113 just with two extra cylinders.

Parts.com is a good place to buy discounted OEM parts. Or, go there and put everything in your shopping cart, then print it out and take it to your dealer parts counter and ask them to match it. They often will do that, but if not, just order from parts.com.

Klinh

It very easy to do. I've done it on my Clk430 and n/a CL55. You will need to change out the 2 breather hoses too because there's no way you can remove the breather hoses from the breather valves cover without breaking the rubbers. The hoses really dried up from engine heat. The driver side is just a little harder beause of the fuel line. I end up removed the fuel line and it made the job easier for me.

Rudeney

Yes, you definitely need to remove the fuel line. You can bleed pressure from the Schrader valve on the fuel rail (standing in front of the engine, it will be on the left side, front of the fuel rail). Us a small container and a rag to catch the fuel at that valve. Then, be ready to catch more fuel when you disconnect the fuel line. This of course means you want to do this in a well ventilated space, and NO SMOKING!

Oh, BTW, just to let you know how easy this job is, I did the C240 with Victor Reinz gaskets, which leaked. Of course on that job, I removed the breather covers, re-sealed them with black RTV, and I also meticulously cleaned the valve covers. When the Reinz gaskets leaked, I bought MBZ rubber. To simply pull the covers and swap the gaskets it took me less than an hour - and that included cleanup. So for a dealer to quote 6.6 hours, they are stealing.

Klinh

I thought about doing that to save $50 and just return the 2 breather hoses. But the crack was too big and so it look cheap. The cleaning the old gasket and cleaning the valve cover with brake cleaner to remove all the oil residue take the longest times.

Klinh

That's unbelieveable !!!!! A couple months ago I brought my Slk55 in for free inspection. They found that my rear brake pad is about 5% left. They asked me if I want them to replace the pads for me and it take about 1.5 hrs. It should only take about 30 mins. Once the car is lift up and the wheel is remove, I can replace the pads in about 10 mins !!!! Remove the reservior fluid cap, knock out the 2 pins, compress the pistons back in by slide the flar head screw drive between the rotor and pad. That's it !!!!

Rudeney

Klinh, on the RTV, I didn't mean using RTV on the rubber hoses (mine rumbled and had to be replaced), but sealing the breather covers to the valve covers - there is no pre-formed gasket for that; they just use RTV. And you are right, to properly clean the breathers and the valve covers takes while. I first used Gunk engine cleaner to get rid of all the, well "gunk", then I went back with MAF cleaner on the mating surfaces because it flashes dry quickly and leaves no residue. I know others use acetone, but spray cleaner is easier.

On the brake job, 1.5 hours sounds about right. ASRA lists it as 8 WU's (5 minutes each, so 40 minutes total). Interestingly enough, that's 4 WU's for removing the wheels, then another 4 for repalcing the brake pads (and that includes checking the fluid levels). So removing a tire takes as long as repalcing pads. Adding rotor replacement is another 11 WU's, so that's a total of 19, or about an hour and a half.

Gary C

Ok got all my goodies from parts.com. 2 gaskets 2 hoses, oil cap gasket and MB RTV . Also got an oil filter and 9 qts of Mobil 1 0w 40 euro blend. Can anybody think of anything else I might need? Also what is the size socket to use. I thought I had the right size, but the son also works on his VW and I seem to be missing a few things I Also bought an oil extractor. So I figure, drain oil. Change filter do the gaskets and when all done add the oil. So you don't have to take fuel pump fuse out and turn car over to bleed the fuel pressure? Going to be doing this on Friday on my day off.

Rudeney

That sounds like everything you need. And no, there is no need to pull the fuel pump fuse - it's not powered with the ignition switch off so just bleed it from the fuel rail Schrader valve.

Gary C

Thanks Rudeney. Also what size socket is it for the valve covers? Any other tools I will need? I will be buying some new ones and figure I would start with the ones I will need for this job.

Gary C

Well I finished my gaskets and did an oil change. Took me 4 hrs, biggest pain was getting the old rtv off the breather covers. Did both sides. The socket was a size e-10 external torx. Now going to take a shower and then have a glass of Crown on the rocks. Knowing I saved about 800 bucks priceless!

Rudeney

I just used a razor blade and scraped carefully. I think there are a lot of warnings about not scratching the surface, but putting RTV back on it, that shouldn't be an issue.

user 823908234

Had oil leaking both sides down onto the exhaust heat shield, noticeable a year ago. Indy shop replaced gaskets both sides.

Four weeks later, +-500 miles, leaking again. He redid them totally on his coin. I check after I get home every evening; easy to see the little wet tracks, plus, I can smell it coming through the air vents if the wind is right.

Another month later, right side leaking. He redid again on his coin.

He'd mentioned after the first re-do that he has seen warped valve covers, and sometimes the groove is too wide and the gasket can roll around. And the last time I was there he showed me a valve cover from a 500 he was working on for the same leak...think it was an E... had to look real close and saw the gasket groove was visibly wider in one area, and there was a tiny crack in the casting right at the groove.

So, this time it took two months, but I saw oil again yesterday. He does not use any gasket compound. Guess I'll be buying at least one new valve cover. BTW, I trust this guy 100%. He is a former MB dealer tech who left because of their crooked attitude. Been in business for himself for many years, not surprising.

Rudeney

Jerry, do you know if he used genuine MBZ gaskets? I wish I had taken the time for a photo, but the Victor Reinz gaskets were noticeably smaller in cross-section than the OEM MBZ gaskets. That's why my C240 kept leaking. The MBZ gaskets really snapped into the covers grooves, where the Reinz gaskets just sat there, and even had to be held in place by hand when positioning the valve cover.

As for warped or cracked valve covers, I am not really sure how that would happen unless someone repalcing the gaskets mishandled them. There are no pressures or mechanical stresses on the covers. I guess maybe someone could have damaged it doing other work, but the valve covers shouldn't just "warp" or "crack" with use. A new valve cover is around $300. I think I might try using some RTV before buying a new one, if mine was warped or cracked.

user 823908234

Hi Rodney, and Merry Christmas!

Thanks for your response. After reading this thread, I'd wondered if he used aftermarket gaskets. I'll find out when he gets back from vacation. He really believes in OEM parts, though. We'll see.

He did mention the price of the covers, that's why he didn't insist on new ones right away. No record that the previous owner had work in that area, unless it was an indy, and it was leaking slightly when I bought it.

On the cover he showed me, I don't recall if there was a bolt hole close to the crack that might have indicated over tightening. It was a casting separation running lengthwise and close to the gasket groove rather than a crack leading from the edge.

I asked him once if he used gasket compound and he was adamant, saying they don't use it in manufacturing, and he spends time cleaning out the groove to make sure it's clean.

I'll keep you informed.

Moedy

That might be your answer right there, get the MB blue sealant from the dealer. You can purchase genuine OEM gaskets from parts.com for less than half what the dealer wants. Put the sealant around the edges before putting the cover on

user 823908234

If it were my DIY, I'd spread compound on that thing like peanut butter.

In one of our discussions he did mention that the gasket should pop in and stay. Other times it fits loose enough to fall out and he puts a dab of sealant to hold it in place so he can get the cover back on.
I'll keep you informed. With pics if I can.

Gary C

I used genuine MB gaskets and did not use sealant on the valve cover. The gasket fit on the groove and stayed there while I put it on. I used the MB sealant on the breather covers. That stuff was black and came in a syringe type container. So far no leaks.

Glyn M Ruck

If you ever have trouble getting the cam box covers to stop weeping a very light application of Yamaha's Yamabond 5 or 6 will do the job. Wonderful stuff that is easy to break & remove.

Used by the racing fraternity globally including F1.

Not suitable for the breather covers. Originally designed for alloy on alloy facings with no gaskets where slight movement might be present due to expansion/contraction etc.

user 823908234

Good information gentlemen, thank you. I really don't want to spend the $ for a new cover. I'll be present when my indy works on it.

Rudeney

If they cracked the cover by over tightening the bolts, then someone really cranked down on them - the prescribed 9Nm is hardly more than hand tight. As for using RTV or other sealants on the gaskets, MBZ specifically recommends against it, but I don't know why - while it shouldn't be needed, it shouldn't hurt anything as long as you don't get blobs of it inside the head.

user 823908234

This is turning into quite the discussion. Thanks, all, for your info and interest. We'll all have to wait for the final conclusion when I take the car back in, which might not be for several weeks. My indy doesn't get back until next week, and I've hardly driven the car recently. So, stay tuned.

Glyn M Ruck

I think Benz attitude is more a matter of should not be necessary with good facings & gaskets. I think they also worry about over application & getting into oil channels etc. Then there is the silicone worry & poisoning O2 sensors & finally the use of acetic acid curing RTV sealers where you can have aggressive attack of alloys.

They probably consider the chance of a foul up too high.

23K

From very recent experience, using MB sealant loctite 5970 above the valve cover gasket does not go off very quickly as its air tight in there to some degree, My casting is very rough in the groove its easy to see why these ALL leak, so i applied a very small amount of 5970 and installed the gasket, next day I removed it again to clear any excess of which there was next to none, later that day I drove the car and the heat caused the soft silicone to be pushed out past the rubber. I will now remove the covers again to clean them. I would assume this is why they recommend not using sealant on the gasket. I suspect even if the sealant had gone off it is very soft and could easy be sqeezed out when the covers are refitted of wheen heat expands and contracts it all.

user 823908234

2 months later, I still haven't taken the car back. I find I'm rather getting fond of the smell of burning synthetic oil. Probably an acquired taste. And it's only a drop here and there. I'll take it back eventually, but right now is tourist season, and my indy is overloaded. I keep a fire extinguisher in the car.