I'm new to owning a Mercedes Benz diesel, and I was wondering how hard is it to replace a head gasket on a 1987 300TD? How long will it take? Are there any special tools required? Are there any things to watch out for?

Background: The mechanic I have taken the 300TD to for inspection says it needs a new head head gasket because it is leaking oil from around the head bolts. I have replaced intake manifold gaskets on my previously owned Ford Mustang before, and I have helped my brother change out his head gasket on his BMW 2002 so I was wondering if how if it was possible to change out a head gasket myself on the 300TD. I have also done other work on suspension and brake parts on various other vehicles but never a head gasket. The only other factor that might influence me is the fact that I don't have a garage so everything will be done in the driveway.

Lastly, how bad is head cracking issue with the OM603 heads? The head on the 300TD is the old "14" casting and I was wondering if it is worth updating to a newer improved head if the old head has no cracks?

Thanks in advance.

-Steve

__________________
1987 300TDT smoke silver w/ burgundy leather interior
2000 VW Passat wagon indigo blue w/ beige leather interior
1985 Mustang SVO
1970 Chevrolet K10 fleetside, shortbed

Here is a web site that will five you info on replacing the head gasket. You will have to explore it in depth, but the info is there. This guy is definitely a good 124 mechanic.
http://www.meimann.com/images/

I think he will give you some idea as to how difficult this job is. I did an 87 300 D Turbo once. There are some tools you will need to do the job right. (3mm threaded Pin Pullers) and a set of good wrenches with a torque wrench.
The main thing is to not get the Pump out of time, and that is easily done. One slip and you will be in deep DoDo. Any milage above 100k and you should change the timing chain and tensioner. If you take the head off, you should do a complete valve job on it. You really need a manual and you can do it if you are skilled and careful.

__________________
Visit my web site and see what it is like living in a Historic town:www.oldsalemhomes.com

The owner of said website is none other than this forum's own gsxr (Dave M.). No one knows 603 heads like Dave.

Oil from head bolts? My guess is that it's the head bolts around the #2 and #3 cylinders and the oil's leaking from the joint between the crossover pipe and the intake manifold and/or the intake manifold and head. AFAIK, the head bolts don't go into oil passages... or weren't mean to. It's certainly worth the price of a crossover pipe gasket and head gasket to be sure you don't have to pull the head. Plus you get to replace the glow plugs if you really need something to do.

There's no reason to replace a head for preventive measures unless you plan to circumnavigate the globe. The progression of head cracks is very slow and the warning signs are easy for a beginner to catch.

I'm from the camp that says that you don't have to replace the chain unless it has stretched or you have everything apart. In fact my 265K mile chain would still be in the SDL if not that the darn pin wouldn't come off so I cut the chain to pull the head and let a machine shop pull the pin. It had 2-3 degrees of stretch at that mileage IIRC.

Sixto
95 S420
87 300SDL

Swogee

Not sure if you've read some of my resent posts but my 603 is leaking oil too and it appears to me to be comming from the rear passengers side of the head and drools down the side of the block. I loose about a quart every 100 miles and my driveway is a mess!

The cross over Sixto is talking about is not where the source of my leak is, but could be yours.

The cracks that you have heard about that some of the 603's heads suffered form as tiny hairline cracks between the valve seats and the injection ports, only about a 1/4" long.

The other problem the heads (all) suffer is corrosion pitting caused from not using MB antifreeze. Some pits can be as large as a quarter and 1/2" deep.

A new replacement head will run you about $1,900 and that does not include valves or much of anything! I stopped inquiring when I discovered what just the head alone cost and can only immagine another grand to have a complete new head. You can buy a whole other car for that money, or buy another engine with lower miles for $2,500 with the "15" upgraded head. There scarce, but if you look long and hard enough, they are available.

I doubt you have such a problem, cracks that is!

I'm going to include new head bolts when I do my head gasket. Use a cable tie to tie together your chain and cam sprocket together before sliding the sprocket of the cam. The chain wont loose it's place that way!

Anyway, good luck and keep us posted.

"17 01" heads are the first known "fixed" heads.

I don't think the oil around the head bolts is the head bolts leaking oil, more likely what sixto already suggested, its leaking out of the intake manifold. Many do that. If you have the original paper gasket, change it for a newer one. If that one leaks, then you can make sure the bolts are tight, seal it with RTV, or just pressure wash your engine from time to time.

There is a main oil line between the block and head in the rear passenger side. My first 603 engine had a leak there too. The other common leak is the front of the passenger side. At 100 miles/qt you may want to pull the head have it pressure tested and lay down another gasket. Or just live with it. Oil is cheap relative to pulling the head.

I've pulled 2 60x heads and almost finished installing one. Only special tools that come to mind are the XZN triple square M10 driver for the head bolts & the shop manual. However, if you haven't touched the engine before there is going to be a LONG lerarning curve so just be patient and keep track of all the parts that come off. I have previously done turbos, manifolds, engine install and removal on these motors so everything was pretty straightforward.

On the issue of slide pins, the dealer has tools for it, but one can make their own with bushings, a bolt and some washers.

Non "MB specific" tools that I have include torque wrenches that can do 10 Nm, 35 Nm (for the head torque), 1/4" & 3/8" drive 5-6 mm allens of various lengths, 1/4" sockets, extensions, ratchets. Having the factory fan removal and install tools help as will an engine hoist or similar to lift the head off the car. If you want to remove the injectors to swap heads, then you'll need a socket for the injectors.

There is NO reason to change the chain at a specific mileage, especially as low as 100Kmi. Measure it and if it needs replacement (4 degrees or getting close), then change it.


Brian

__________________
Brian Toscano

Thanks for all of the replies. It looks like I would be better off keeping the original cylinder head since the new ones run a lot of money and the original head doesn't show any signs of cracking.

It also seems that oil leaks generally are not the caused by a head gasket leak, but by other items such as the intake manifold gasket and oil lines if I am reading all of the posts correctly.

Sixto, did you mean to say "its worth the price of a crossover pipe gasket and intake manifold gasket"? The car is at the mechanic, and I need to ask them some questions as to where they found the oil leaks. The glow plugs supposedly aren't more than a year old. I can go for replacing an intake manifold gasket and crossover pipe gasket first over a head gasket.

My 300TD has 180K miles. How does one check the chain stetch? Are there any obvious signs of chain stretch? One sign I heard of was smoke at idle even after warming up.

Finally it sounds like I can pull the head myself but it will take time to figure it out even after reading the shop manual. I am generally pretty careful, but the idea of pulling the head doesn't appeal to me.

-Steve

__________________
1987 300TDT smoke silver w/ burgundy leather interior
2000 VW Passat wagon indigo blue w/ beige leather interior
1985 Mustang SVO
1970 Chevrolet K10 fleetside, shortbed

I meant that it's a good gamble for the cost to improve the seal at those joints in hopes that this will clear up oil around the head bolts near the #2 and #3 injectors.

If your mechanic suspects a bad head, he's either good enough to have discounted manifold leaks or unfamiliar with these engines. I'd strongly consider taking the car to some someone more familiar wth these engines if you're not dealing with an expert.

Sixto
95 S420
87 300SDL

Looks like a reply I typed up did not make it.

"oil passages" would be more clear.

If he really thinks oil is oozing out of the head bolts & doesn't think its the intake manifold gasket, I would take it to another shop, at least for a 2nd opinion.

At 100 miles/qt I would probably pull the head and fix it - if I was going to keep the car for a while. But be prepared to replace the head at the time you do it. I say that because if I pulled the original head I would have it skimmed & pressure tested and if it failed, I would replace it. I suspect many of these heads have issues & that not all the issues are obvious for some time. However, if the head comes off I would not want to have to do it again because I cut corners the 1st time around

__________________
Brian Toscano