will 91 350sdl with "crate motor" be Reliable non Rodbender? - PeachParts Mercedes-Benz Forum

wallbenz · #1 11-04-2019, 01:25 PM

I am still in the hunt for 87SDL or 91-350sdl...

Seems like the 350sdl's- 50/50 chance of being rodbender
what are the odds of The Crate Motor being Rodbender?

looking for wisdom

barry12345 · #2 11-04-2019, 02:11 PM

Some of the crate replacement motors went bad as well. If it had been a cure they would have recalled all the cars with those 3.5 engines and changed the rods. Before the cylinder walls where damaged.

I believe these cars where in the 70 to 80K price range. If I found one I liked. There are still good solid 3 liter lower blocks available used. I would buy one and put it in storage. I also would factor that into the buy price somewhat.

I would be prepared to change it out myself if the need occurred. If you have to pay for someone else to do it again may impact what you pay for the car somewhat. The engine a 3.5 may also last. The issue is you just do not really know.

The better 3.5 cylinder head in combination with the 3 liter bottom block is probably almost bulletproof. To sum it up do not wear rose colored glasses when buying a 3.5 liter car. The odds of failure may be slightly less if the car got a replacement engine with stronger rods. Yet to me it still exists.

In todays world a class action suite would probably have happened. That was a lot more money back then to have this problematic of an engine. North American dealers had been screaming to the manufacturer that the car was underpowered. In a rush in my mind Mercedes made an error.. The head issues took the 3 liter engine off the market.

Then it came back years later with a good head and a bad bottom end. s Mercedes never told the actual cause of this issue because of liability issues I imagine. They may not have sold a lot of these engines in Europe. I remember a few years ago some people from over there claimed they were not seeing the problem.

The only difference I can think of and thats if the story is true was better fuel. European diesel fuel is known to be better. Since we have premium diesel fuel up here in Canada. I would run it in that engine myself. They tell me that premium diesel fuel is scarce to non existant south of the border. I did not even know it existed here until the seller of our last diesel car told me. Even the premium diesel fuel up here is still not as good as the European diesel. It is better than our regular diesel. It also is loaded with detergents. Plus an additive that increases fuel milage. By raising the celaine rating. It is very hard to get an accurate fuel consumption rate that I can believe in though.

I have to assume my dash indicator at so many liters per 100 kilometers or 62 miles is optimistic. Every opportunity I get to use the wives car at least for 250 miles I fill the tank as best I can. I drive it easy and when I get back fill the tank again. Same pump and on the same grade if any facing the same way. I just cannot get a similar fill up in my opinion.

The engine is programed for a wider torque band and better fuel milage than the Jettas and Golfs. Yet the car is larger and heavier with wider tires. We just got back from closing the cottage up. With 850 killomters or around 500 miles on the trip meter and still not down to the half tank yet. The wife had had the car out on the highway before we went to the cottage. Plus that fuel gauge does not take long to come off the full position. It may be the premium diesel fuel. Why all the information of the wives car? If you can find any upgraded fuel in America I would recommend trying it.

I have been driving diesels before many site members where born. No two countries that have it are formulating it the same. For what it is worth a visiting American that really knows diesels. They repair them and sell parts. Claims he was really impressed with the fuel when he was up here on vacation. I have not put my daily diesel beater on it yet but will. I am sensitive enough to that car to notice any difference and will post it one way or another.

As for the price to install a head on the block pull the old engine and install the other one. You want a guy that is good and has reasonable rates. In your area it may be easier to find one than in others. Price could be all over the place. He has to know what he is doing. It is not rocket science to know how.

wallbenz · #3 11-04-2019, 02:29 PM

Quote:

Originally Posted by barry12345

Some of the crate replacement motors went bad as well. If it had been a cure they would have recalled all the cars with those 3.5 engines and changed the rods. Before the cylinder walls where damaged.

I believe these cars where in the 70 to 80K price range. If I found one I liked. There are still good solid 3 liter lower blocks available used. I would buy one and put it in storage. I also would factor that into the buy price somewhat.

I would be prepared to change it out myself if the need occurred. If you have to pay for someone else to do it again may impact what you pay for the car somewhat. The engine a 3.5 may also last. The issue is you just do not really know.

The better 3.5 cylinder head in combination with the 3 liter bottom block is probably almost bulletproof. To sum it up do not wear rose colored glasses when buying a 3.5 liter car. The odds of failure may be slightly less if the car got a replacement engine with stronger rods. Yet to me it still exists.

In todays world a class action suite would probably have happened. That was a lot more money back then to have this problematic of an engine.

what is "ballpark" cost from a reasonable Indy- to replace 3.5 with a 3.0l stored motor block?

any idea what % of the Crate motors failed?

sounds- like it might be best to look ONLY at the 87-300sdl's
even though this Interior/seating looks really improved in the 91 SDL

does the 91 SDL- have any other computer /advance designs that make it better/worse choice versus 87sdl

t walgamuth · #4 11-04-2019, 04:06 PM

If you are asking what the labor is to switch out a complete motor I would estimate from $500 to 1000 labor only. I imagine some parts might be needed so I'd budget another 500 to 750 for misc. parts.

Yes the earlier 300 sdl would probably be nice if in good serviceable condition, but I imagine they are scarce.

barry12345 · #5 11-04-2019, 04:31 PM

If the 1987 has the #14 head. It may fail at some point as well. It was their weak point. Many have had upgraded heads by now. Also certain of their gas cars that are older now are cheaper and probably give about the same fuel milage. Certainly should be easier to find. You are in the Chicago area so watch out for rust.

Volvo Diesel · #6 11-04-2019, 05:14 PM

An '87 300SDL is 32 years old; a '91 SDL is 28 years old. At either age (and with the mileage these cars often have when for sale), you're likely to have some issues with the car that will cost money to fix. The questions you ask in this (and other) threads suggest you are concerned about the costs involved in keeping whatever vehicle you purchase on the road. You need to make sure you understand that driving a W126 diesel (whether 617- or 603-powered) "from 200,000 miles to 300,000 miles" is going to cost you money, period. How much it costs you will depend on how much of the maintenance you are planning on performing yourself. Bent rods on the '91? Could happen. Cracked head on the '87? Might happen, too. Head gasket or transmission failure on either? It's a possibility. Suspension rebuild necessary? Quite possibly.

Look, I love my '85 300D. I've had it for about 20 years now. Driving it just feels familiar-it's like putting on the winter coat my dad gave me when I graduated high school. But, honestly, if reliability and cost were my main concerns, I'd buy a seven year old Toyota Camry for $4000, change the oil twice a year, buy tires when it needs them, and just drive. That's my two cents...

bsmuwk · #7 11-04-2019, 05:33 PM

Replacement factory "crate" motors do not fail...at least not in the manner most individuals have been describing all over forums for years. I service about 40 cars with this engine and only one of them had properly bent a rod on cyl 1. You'll find there are engines with replacement tags found on the bellhousing near the transmission on the passenger side. It's an aluminum tag riveted to the block - should you find it, that motor has been replaced. You'll be OK buying that engine!

I've seen a considerable number of these engines misdiagnosed for bending rods, when in fact the head gasket oil passage in between the timing case and cylinder #1 lets go and ends up flooding cyl #1 with oil on start up - you'll have heavy oil burning and a very apparent misfire on colder starts. The exhaust will also start building up a heavy deposit of oily soot. The repair? A headgasket. What causes the failure, no idea. I've stepped up the torque in that area when assembling these engines and it seems to have solved the problem. Though the sample size is small (120k miles on a personal vehicle, and cumulatively 220k among customer vehicles).

I did a customer's 350GD a couple years back that had a catastrophic failure of that oil passage after the owner hadn't repaired it. The truck traveled all of Africa, Greece, UK, etc before the engine hydrolocked itself on it's own oil. I've attached a picture of that failure and of the engine at the end of that whole escapade.

These car's cost money, if you're buying one for utter reliability with minimal investment, you're not going to get it. You'll be spending thousands to get a car together that will be mechanically reliable. Same goes for every MB diesel out there - realistically the operating and maintenance cost of a 560SEL is less than that of the diesel.

If you do find yourself a car, feel free to make the drive up to my shop in Lakemoor to get it checked out, I'm happy to help! I'm a block away from the Volo museum, so it's a cool place to hang out.

t walgamuth · #8 11-04-2019, 06:07 PM

Quote:

Originally Posted by bsmuwk

Replacement factory "crate" motors do not fail...at least not in the manner most individuals have been describing all over forums for years. I service about 40 cars with this engine and only one of them had properly bent a rod on cyl 1. You'll find there are engines with replacement tags found on the bellhousing near the transmission on the passenger side. It's an aluminum tag riveted to the block - should you find it, that motor has been replaced. You'll be OK buying that engine!

I've seen a considerable number of these engines misdiagnosed for bending rods, when in fact the head gasket oil passage in between the timing case and cylinder #1 lets go and ends up flooding cyl #1 with oil on start up - you'll have heavy oil burning and a very apparent misfire on colder starts. The exhaust will also start building up a heavy deposit of oily soot. The repair? A headgasket. What causes the failure, no idea. I've stepped up the torque in that area when assembling these engines and it seems to have solved the problem. Though the sample size is small (120k miles on a personal vehicle, and cumulatively 220k among customer vehicles).

I did a customer's 350GD a couple years back that had a catastrophic failure of that oil passage after the owner hadn't repaired it. The truck traveled all of Africa, Greece, UK, etc before the engine hydrolocked itself on it's own oil. I've attached a picture of that failure and of the engine at the end of that whole escapade.

These car's cost money, if you're buying one for utter reliability with minimal investment, you're not going to get it. You'll be spending thousands to get a car together that will be mechanically reliable. Same goes for every MB diesel out there - realistically the operating and maintenance cost of a 560SEL is less than that of the diesel.

If you do find yourself a car, feel free to make the drive up to my shop in Lakemoor to get it checked out, I'm happy to help! I'm a block away from the Volo museum, so it's a cool place to hang out.

We are in agreement.

The leaking oil from a failed or partially failed head gasket causes full or partial hydrolock.

Perhaps if one took the 3.5 motor and changed the head gasket every 50k preemptively it would run for 500K.

zloca944 · #9 11-04-2019, 06:09 PM

Quote:

Originally Posted by barry12345

They may not have sold a lot of these engines in Europe. I remember a few years ago some people from over there claimed they were not seeing the problem.

.

We have A LOT of 3.5 here in Europe in W140 chassis,and in my country they"survived"much better then the ones with petrol engines and now in car sales websites we have much more diesel W140 then the ones with petrol engines

.And I have never ever seen a 3.5 W140 with oval cylinder,the only"problem"they have is warped head and cylinder head gasket leak because of the bad and poorly maintained cooling system so the owner overheat them on a hot day.So who knows maybe it has something with fuel quality

I drive OM603 W140 for 10 years as a DD and would not change it for nothing else

bsmuwk · #10 11-04-2019, 06:43 PM

Quote:

Originally Posted by t walgamuth

We are in agreement.

The leaking oil from a failed or partially failed head gasket causes full or partial hydrolock.

Perhaps if one took the 3.5 motor and changed the head gasket every 50k preemptively it would run for 500K.

50k may be too little of mileage, I'm seeing "replacement" engines around the 120-180k mark blowing through the gaskets. One of my personal vehicles (92 300SD), is running a non replacement engine at 300k miles. I did the headgasket at 180k with an increase in torque on the timing cover area bolts just to see what it'll do as an experiment. No loss to me if it fails, it see's a full throttle run every time the engine is started - so far it's going well. I'd like to get in that 180k mile range on the job to see if it'll hold up or if it'll be another statistic. The engine also has a hybrid turbo and pump turned up, so any stresses it sees are higher than standard.

wallbenz · #11 11-04-2019, 08:09 PM

Quote:

Originally Posted by Volvo Diesel

An '87 300SDL is 32 years old; a '91 SDL is 28 years old. At either age (and with the mileage these cars often have when for sale), you're likely to have some issues with the car that will cost money to fix. The questions you ask in this (and other) threads suggest you are concerned about the costs involved in keeping whatever vehicle you purchase on the road. You need to make sure you understand that driving a W126 diesel (whether 617- or 603-powered) "from 200,000 miles to 300,000 miles" is going to cost you money, period. How much it costs you will depend on how much of the maintenance you are planning on performing yourself. Bent rods on the '91? Could happen. Cracked head on the '87? Might happen, too. Head gasket or transmission failure on either? It's a possibility. Suspension rebuild necessary? Quite possibly.

Look, I love my '85 300D. I've had it for about 20 years now. Driving it just feels familiar-it's like putting on the winter coat my dad gave me when I graduated high school. But, honestly, if reliability and cost were my main concerns, I'd buy a seven year old Toyota Camry for $4000, change the oil twice a year, buy tires when it needs them, and just drive. That's my two cents...

Point taken- but please understand- my concern regarding the "costs" to keep rolling on the road... 1st - I do have the money- but like to think I am frugal (some might even say cheap)... and I can afford to pay for a $70K car... but NOT my personality... I currently drive 200k mile Honda.

I like this vintage MB Diesel- cause I "gambled on a 80k 300sd 27 years ago"... and it was one of the cheapest cars I ever owned ( Honda CRV #1)...
That 84 300sd was still the best Highway driver - I owned- for sure-classy

Anyways- I EXPECT to have maintenance costs... over several years... I just don't want to spend more- than it would cost me to buy for example 36K new Pilot and drive trouble free for 10-12 years... so $5k purchase and 15K over several years maint.--- no problem... but if we are talking more like over $20k in maint.--- now I am losing to the New pilot... even if it were even $ to $...

With the MB --I have a better/classic/ smooth MB Diesel that I would be proud of- and comfortable in ( as long as the spring/seat is right).

In addition- I would still keep my awd Honda for snow/winters

wallbenz · #12 11-04-2019, 08:37 PM

Quote:

Originally Posted by bsmuwk

Replacement factory "crate" motors do not fail...at least not in the manner most individuals have been describing all over forums for years. I service about 40 cars with this engine and only one of them had properly bent a rod on cyl 1. You'll find there are engines with replacement tags found on the bellhousing near the transmission on the passenger side. It's an aluminum tag riveted to the block - should you find it, that motor has been replaced. You'll be OK buying that engine!

I've seen a considerable number of these engines misdiagnosed for bending rods, when in fact the head gasket oil passage in between the timing case and cylinder #1 lets go and ends up flooding cyl #1 with oil on start up - you'll have heavy oil burning and a very apparent misfire on colder starts. The exhaust will also start building up a heavy deposit of oily soot. The repair? A headgasket. What causes the failure, no idea. I've stepped up the torque in that area when assembling these engines and it seems to have solved the problem. Though the sample size is small (120k miles on a personal vehicle, and cumulatively 220k among customer vehicles).

I did a customer's 350GD a couple years back that had a catastrophic failure of that oil passage after the owner hadn't repaired it. The truck traveled all of Africa, Greece, UK, etc before the engine hydrolocked itself on it's own oil. I've attached a picture of that failure and of the engine at the end of that whole escapade.

These car's cost money, if you're buying one for utter reliability with minimal investment, you're not going to get it. You'll be spending thousands to get a car together that will be mechanically reliable. Same goes for every MB diesel out there - realistically the operating and maintenance cost of a 560SEL is less than that of the diesel.

If you do find yourself a car, feel free to make the drive up to my shop in Lakemoor to get it checked out, I'm happy to help! I'm a block away from the Volo museum, so it's a cool place to hang out.

So you are confident that a true Crate motor 91-350sdl-- will NOT be a rodbender?

I went to your website- good stuff... if i do find the MB Diesel - will certainly stop by...

I am confused by one point--- my old MB (300sd) mechanic - had me believe that the Diesel was cheaper- to own/maintian vs. MB gassers.

Anyways- loved that om617... just looking to get a little quicker/newer w/ 87 sdl or 91 sdl with Crate motor... and trying to do more research on how WELL/Reliable the crate motor really was...

Very interesting reading- about rodbender theories.... what are your thoughts on the Sulfur in US diesel being one of the factors... seems a little logical if same motors in Euro cars- were NOT bending like in US???

I will reach out to you via PM or phone... to verify a TAGGED motor

thx

Volvo Diesel · #13 11-04-2019, 09:16 PM

Quote:

Originally Posted by wallbenz

Anyways- I EXPECT to have maintenance costs... over several years... I just don't want to spend more- than it would cost me to buy for example 36K new Pilot and drive trouble free for 10-12 years... so $5k purchase and 15K over several years maint.--- no problem... but if we are talking more like over $20k in maint.--- now I am losing to the New pilot... even if it were even $ to $...

Then I’d buy the nicest one I could find with a verified maintenance history and hope for the best. Good luck in your search. They are well made cars that perform nicely out on the road.

bsmuwk · #14 11-04-2019, 09:38 PM

Quote:

Originally Posted by wallbenz

So you are confident that a true Crate motor 91-350sdl-- will NOT be a rodbender?

I went to your website- good stuff... if i do find the MB Diesel - will certainly stop by...

I am confused by one point--- my old MB (300sd) mechanic - had me believe that the Diesel was cheaper- to own/maintian vs. MB gassers.

Anyways- loved that om617... just looking to get a little quicker/newer w/ 87 sdl or 91 sdl with Crate motor... and trying to do more research on how WELL/Reliable the crate motor really was...

Very interesting reading- about rodbender theories.... what are your thoughts on the Sulfur in US diesel being one of the factors... seems a little logical if same motors in Euro cars- were NOT bending like in US???

I will reach out to you via PM or phone... to verify a TAGGED motor

thx

A true replacement engine will not be a bender on principle. HOWEVER, the engine does remain susceptible to gasket failures and if not treated before it becomes a serious problem it will cause catastrophic failures...which include bending rods from not being able to compress excess liquids injected into the cylinder. If it's maintained regularly and investigatory measures are taken when oil loss is noted, it will provide a service life to rival an OM617. For what it's worth, I've replaced more blown up OM617's than I have blown up OM603's.

In general your entry fee and initial repairs are considerably greater with diesels as they are plagued with overall deferred maintenance. People assume the diesel doesn't need as much maintenance as a gas engine, but realistically the engine is just more forgiving to a lack of maintenance. Todays fuel costs, oil changes, over $1k repair tickets for major assemblies, etc also factor into the overall running costs over a 10 year period. Out of all the Mercs I own, over the course of 10k miles the V12 SL's have been the least expensive and most reliable. Go figure, right?

I believe Mercedes had a note somewhere on fuel quality in the states, it had more to do with cetane levels causing the engine to detonate and deform rods. It's in my experience that it may have been true, but the detonation actually caused premature failure of the head gasket and the engine was compressing it's own engine oil...causing the bent rod. It's ALWAYS cyl 1!

wallbenz · #15 11-04-2019, 10:43 PM

I believe Mercedes had a note somewhere on fuel quality in the states, it had more to do with cetane levels causing the engine to detonate and deform rods. It's in my experience that it may have been true, but the detonation actually caused premature failure of the head gasket and the engine was compressing it's own engine oil...causing the bent rod. It's ALWAYS cyl 1![/QUOTE]

Forgive me- but did US fuel have higher or lower cetane levels than Europe back then? Causing engine/detonation/rod issues... reason I ask- is I always used Redline fuel add in my om617.... and I assume that Redline boosted the cetane? My 300sd- was a fantastic car... that never stranded me for over 200k miles- til she was 20 years old.

The ONLY bad issues w/ that car were terrible window regulators and plastic clips failing... and antenna was a joke...

did they improve windows on the 87 sdl or 91 sdl??? I hope!