Feeling is mutual Bob. I’d like nothing better than being at Carlisle and meet some of my addiction enablers...
We will roll out the socialist red carpet for you no problem...
MDS Explanation
- Thread starter 1978 NYB
- Start date
Feeling is mutual Bob. I’d like nothing better than being at Carlisle and meet some of my addiction enablers...
We will roll out the socialist red carpet for you no problem...
Carmine
Old Man with a Hat
Not really... two left outer bank, two right inner bank.
Just had a Ram in with 330000kms that had a seized lifter....first one in a while. Mostly see broken valve springs on the high mileage stuff.
How does "maintenance" seem to affect things with the MDS? Or using incorrect viscosity oil? Just curious.
There apparently are more issues with the Direct Injection motors than just intake tract deposits. Joe Gibbs has come out with a DI-specific motor oil, as have a few others upgraded their additive packages for these motors. Injected fuel apparently doesn't have enough "evaporation time" before the spark, for it all to burn as good as it should?
CBODY67
There apparently are more issues with the Direct Injection motors than just intake tract deposits. Joe Gibbs has come out with a DI-specific motor oil, as have a few others upgraded their additive packages for these motors. Injected fuel apparently doesn't have enough "evaporation time" before the spark, for it all to burn as good as it should?
CBODY67
Carmine
Old Man with a Hat
Use correct viscosity oil.
I was able to drive my Challenger up to 80 mph in 4 cyl. mode (on level ground).
It's a good system. Of course any additional layer of tech brings another potential failure, but on that basis we'd be driving flathead Model T's.
That is certainly part of the problem. The other issue is that the 4 cylinders that go dead with the MDS do not have any compression gas to hold the upper rings tight against the cylinder walls, that is a ready made formula for fouling of the ring grooves as oil can collect there and get cooked into carbon deposits when the dead cylinders come back to life under full load.. Synthetics and the updated conventional oils are supposed to have additives to reduce fouling in that situation.
Dave
Isn't this the oil that Mopar uses in our vehicles for engine oil changes?
Not sure if it is Pennzoil or not. It do remember a service advisory someplace about using 10-30w rather than the 5-30w. The slightly heavier viscosity is supposed to be better for the lower end.
Dave
I think my owners manual says 5W20 for my 2018 5.7L.
Feeling is mutual Bob. I’d like nothing better than being at Carlisle and meet some of my addiction enablers...
We will roll out the socialist red carpet for you no problem...
Be sure to impose a tax to cover the cost of the "Red" carpet.
Dave
So now I want to know a little more... The Achilles heal of the caddy 4/6/8 and the MB 6/12 in the early 2000's was that they left the cylinders off for too long. The pumping action of the piston eventually fouled the cylinder with oil and then when the owner finally did bring on those cylinders they would get some amount of misfiring.
The understanding I have had of the engines where this works over the last decade or so... has been that they use a strategy to fire those cylinders often enough to prevent the oil fouling.
In short, am I correct? Any expansion on the explanation?
The issue with the 5-30w oils was that under severe service conditions, such as pulling a trailer or high speed operation, the bearings were not being protected enough by the thin oil (not enough cushion). If you are not doing any severe applications, you probably can use the 5-30w, if the warranty specifies that oil.
Dave
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In practice, I don't think that even on longer runs on the highway, the MDS will be "on" all of the time. Every time you might go over an overpass, there's a good chance it will kick "off" until the overpass is topped. Any incline can kick it out, due to the increased load the engine sees. Kind of like watching the instant fuel economy gauge in the DIC, it's always changing (more than might be suspected). IF you're driving with a tail wind, as flaky as that might seem, more MDS "on" time, by observation.
CBODY67
CBODY67
300rag
It's Not Going to Shift Itself
From my recollection, both engine and transmission have to be above a preset limit before the system will operate.
300rag
It's Not Going to Shift Itself
I have observed my instantaneous mileage readings actually be better in certain instances when the system is off. I have on occasion turned the MDS off while running on the highway on level ground, and in some cases, the mileage will increase slightly, and then drop again when it is enabled. I think it is near the point where the system would change on its' own anyway.
65sporty
Old Man with a Hat
The correct viscosity oil is important as well as if it's a semi or full synthetic oil, oil change intervals also very critical. Don't just follow the monitor. I have customers that come in and give me the I still have 30 percent left but they have 6,000 miles on it. Pay me now or pay me later. Check the owners manual to see what they recommend for intervals, most of the drivers in my area would fall into the severe duty category.
The MDS is dependant on viscosity to the point that if the wrong viscosity is used the PCM will register it as a fault and set a CEL code. The system is in and out so often that there is little chance of fouling.
bajajoaquin
Senior Member
Not true. My grandparents had an Eldorado with this engine in the 80s. I remember sitting in the back seat and watching the indicator showing how many cylinders were working. It cycled a lot. It may have been rough in six cylinder mode, but it didn’t spend much time there. It was almost always in four or eight cylinder operation.
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