Looking at a 1987 300 SDL, issues? - PeachParts Mercedes-Benz Forum

mikeyfev1 · #1 06-25-2012, 01:10 AM

Hello,

I will be looking at a 1987 300 SDL soon. What sort of issues should I be watching for?

Specifically, how do I identify the head type on this engine? I have read some of the stories about the 603 heads and I don't want to step into a bad situation.

Thanks for any help!

vstech · #2 06-25-2012, 01:29 AM

the issue with the head is overstated.

a perfectly functioning cooling system and the original head will last a LONNNNNNNNG time.

if the belt breaks, STOP THE CAR!!!

keep all the maintenance up, and the head will give no issues.

forgo maintenance, and drive "till the next exit" and you will need to replace the head.

if the coolant is not clean and clear, if the belt looks badly worn, if the engine is not running perfectly, these are signs the car is a bad choice.

if you look between the injectors #1 and 2, down towards the block you will find the casting numbers.

davidlee · #3 06-25-2012, 03:17 AM

If you look between the first and second intake runner you will see the head numbers.
example::: 47822356, (22) is the head number
exp2:: 86314865, (14) is the head number

it is pretty easy to spot, out of all the numbers, there will only be 2 numbers side by side that spell out a number between 14 and 22, what ever that number is, that is the head you have.
the higher the number (starting at 14, going up to 22), the more advancements done to the casting to prevent future overheating issues,
basically, in a nut shell, as their numbers got higher, Mercedes made design changes to help the head cope better with higher heat without failure. obviously if any cooling system failure occurs, no matter what head you have you could possibly be looking at head damage.

If there are no maintenance records with the car you purchase, a belt, and radiator are always good upgrades, & make sure to only use non phosphate coolant no matter head #

Brian Carlton · #4 06-25-2012, 11:35 AM

Quote:

Originally Posted by mikeyfev1

Hello,

I will be looking at a 1987 300 SDL soon. What sort of issues should I be watching for?

The average forum member has no capability of finding the "sorts of issues" on this vehicle by casual inspection. The vehicle is fraught with the possibility of many old components that need replacement. It's entirely possible to spend $15K in maintenance and repairs on such a vehicle in the first two or three years if a mechanic is utilized.

Therefore, unless the seller has a detailed maintenance and repair log for this vehicle, you may assume that YOU will be the one replacing all the worn components on it. For parts alone, budget $5K, not including any labor if you manage to do it all yourself.

If the transmission has 250K on it, you can figure another $2.5K for that.

Folks will caution you regarding the aluminum head on these vehicles and direct you to look for a casting number. The later casting numbers have some additional improvements in the casting, but by no means does it guarantee a head in proper operating condition. The condition of the head is nearly impossible for the casual buyer to discern.

Jeremy5848 · #5 06-25-2012, 12:21 PM

Brian makes some excellent points, as usual. Face it, friend, this is a 25 year old car. Lots of things could have gone wrong and been ignored by previous owners. For every problem the seller admits you can be sure the car has two others: one that the seller didn't know about and one he "forgot" to disclose. Finding and fixing these problems takes time and money. In addition to the usual engine and transmission issues, some expensive items on this vehicle include the front and rear suspensions, the sunroof, and the climate control system.

Unless the seller has records showing work done you should assume that just about everything you look at needs work. You should be shopping, not for a good car, but for a good set of service records showing the car has been cared for. Looking at the car, especially as a newbie, will not tell you enough to allow you to make an intelligent decision.

This is not to discourage you from looking for a car of this type. Good ones are out there but you have to know exactly what to look for and you do not, as I did not when I bought my second Benz, some years ago. It was an expensive lesson and today I know a lot more than I did in 2006. I would rather you do not emulate the ignoramus I was then. (At least you had the good sense to ask!)

Jeremy

ah-kay · #6 06-25-2012, 12:42 PM

Quote:

Originally Posted by Jeremy5848

I did not when I bought my second Benz, some years ago. It was an expensive lesson and today I know a lot more than I did in 2006. I would rather you do not emulate the ignoramus I was then. (At least you had the good sense to ask!)

Jeremy

You did not tell the OP anything new. What expensive lesson you learned? Can you share?

I can share some of my thoughts on a 25+ old cars. Nothing will stop a car from breaking down even with a good maintenance record. You would expect to fix minor issues like leak/window does not work/knackered switches/weeping PS hoses etc. All these are within the realm of an average DIY. These are issues I observed, plus the above.

1) Leaking bottom seal on IP. you will see a puddle of engine oil on the engine mount.
2) ODO quit
3) Door check failed.
4) I would not worry about #14 head. It is overblown. Is it a potential issue, of course, otherwise MBZ would not rev the version.

Good luck.

winmutt · #7 06-25-2012, 06:29 PM

If it's got a #22 head, buy it.

Bio300TDTdriver · #8 06-25-2012, 09:45 PM

Quote:

Originally Posted by vstech

the issue with the head is overstated.

Quote:

Originally Posted by ah-kay

4) I would not worry about #14 head. It is overblown.

It's not overstated or overblown when it happens to you. It is merely cracked and or warped and needs to be replaced.

Brian Carlton · #9 06-25-2012, 09:49 PM

Quote:

Originally Posted by Bio300TDTdriver

It's not overstated or overblown when it happens to you. It is merely cracked and or warped and needs to be replaced.

Yep.

It's "overstated" when it happens to others...........not you.

When it happens to you, "why didn't somebody tell me about cracks"?????

ah-kay · #10 06-25-2012, 09:56 PM

Quote:

Originally Posted by Bio300TDTdriver

It's not overstated or overblown when it happens to you. It is merely cracked and or warped and needs to be replaced.

Please do not scare the daylight out of any potential buyers of om603. The followings have happened to the om603 engines at one time or another, so what do you do?

1) Vacuum pump disintegrated
2) Timing chain snapped
3) IP crapped out
4) #14 head cracked or warped.

These are just a few I can think of. I am sure there are others issues. I would buy a good running om603 with #14 head in a heart beat. If it comes with a #22 head then I would buy it also

. Please put things into perspective and do not overstate anything. Engine has a lot of failure mode, the #14 head is one of them but NOT the only one.

Bio300TDTdriver · #11 06-25-2012, 10:05 PM

Quote:

Originally Posted by ah-kay

Please do not scare the daylight out of any potential buyers of om603. The followings have happened to the om603 engines at one time or another, so what do you do?

1) Vacuum pump disintegrated
2) Timing chain snapped
3) IP crapped out
4) #14 head cracked or warped.

These are just a few I can think of. I am sure there are others issues. I would buy a good running om603 with #14 head in a heart beat. If it comes with a #22 head then I would buy it also

. Please put things into perspective and do not overstate anything. Engine has a lot of failure mode, the #14 head is one of them but NOT the only one.

One man's scaring the daylights out of is another man's simple warning. I think if I were trying to scare the daylights out of them I would have posted a picture of the head along with the receipt for the new head, etc. Now that really is scary.

Since the OP asked what to watch for I certainly think a cracked head makes the list. The old style vacuum pump should also be on the list.

Brian Carlton · #12 06-25-2012, 10:14 PM

Quote:

Originally Posted by Bio300TDTdriver

Since the OP asked what to watch for I certainly think a cracked head makes the list.

The problem is the simple fact that no potential purchaser of this vehicle has the skills or the equipment to determine if the head is cracked...........prior to purchase.

I'll discount the few examples that have oil in the coolant reservoir.

Bio300TDTdriver · #13 06-25-2012, 10:17 PM

Quote:

Originally Posted by Brian Carlton

The problem is the simple fact that no potential purchaser of this vehicle has the skills or the equipment to determine if the head is cracked...........prior to purchase.

I'll discount the few examples that have oil in the coolant reservoir.

A stiff upper radiator hose on a cold engine wouldn't cause you to pass on a car? It would me.

Brian Carlton · #14 06-25-2012, 10:25 PM

Quote:

Originally Posted by Bio300TDTdriver

A stiff upper radiator hose on a cold engine wouldn't cause you to pass on a car? It would me.

When I refer to a potential purchaser, I am not considering those that have prior experience with this engine. A person who has never owned one of these is highly unlikely to reject the vehicle if the upper hose is stiff.

Furthermore, the upper hose won't be stiff if the vehicle has been sitting a few days prior to starting. Also, odds are that the PO has started it once on the day it is viewed, leaving the test moot.

ChiefRider · #15 06-25-2012, 11:04 PM

Do your research on the om603, and verify the car has been well maintained. The 126 chassis is possibly one of the best cars ever built, but as has been said, maintenance and upkeep are paramount, and you would quickly exceed the value of the car if there is much to be done. A good example can be a real pleasure.