Official Cummins QSC-500 Thread

I get a small weep of oil from around my port dipstick. Evidently, it's a known Cummins issue. Cummins has a new style dipstick and tube to correct this, but they did not issue a recall for it, rather it is an upgrade.

They want a bit over a boat buck to replace with the 'new' style dipsticks. Has anyone done this?
 
Just a weep, for a boat buck $$ I can wipe it as I check my oil weekly. If it is dripping then I fix.
 
Tks Grant

I'm monitoring...
FWIW, I was told it affects the port engine on my boat more than the starboard based on where the dipstick tube is located.
The part numbers if anyone is interested:
3969043 Locking Dipstick
3957577 Locking Dipstick Tube
 
oil dipstick.jpg

After about 3 hours in the ocean.
The more annoying part is the oil runs along the pan rail and drips in various spots.
Think I just answered my own question and will get it done, unless someone has a suggestion?? PLEASE!?!?
 
I have a leak on the starboard engine near the dipstick tube but it seams to be leaking from the oil separator return line which dumps in right there. Tried tightening it but still get a slight weep. My bilge Pig Blanket catches the oil and I just replace it at service intervals.
 
Hi all, we've been looking at 420DA's that mostly have the mechanical 6CTA's. Since the market is so thin, I've expanded to the newer 44DA's that mostly have the QSC500's. In my research up to this point it doesn't seem like these QSC's have the colored past of the 480CE and some others- is that true?

I know the basics apply: maintenance, WOT RPM and overload check, oil samples, etc, but are there are QSC gremlins or major known issues on this engine (specifically to the 44DA if that matters)?
 
Strecker25 said:
Hi all, we've been looking at 420DA's that mostly have the mechanical 6CTA's. Since the market is so thin, I've expanded to the newer 44DA's that mostly have the QSC500's. In my research up to this point it doesn't seem like these QSC's have the colored past of the 480CE and some others- is that true?

I know the basics apply: maintenance, WOT RPM and overload check, oil samples, etc, but are there are QSC gremlins or major known issues on this engine (specifically to the 44DA if that matters)?
Click to expand...
Its True! As I understand it, the boat manufacturers in the early 2000s wanted to build sexier faster boats but Cummins did not have a 500 HP engine to sell them so they just supped up the 480s a little and put bigger props on them for better top end performance with out regard for longevity. The QSCs were just a better thought out and engineered revision of the same engine and as such has had none of the issues that the 480CE line suffered. I love mine and have really had no issues in 450 hrs save for a harness fail and that had no effect on performance just instrumentation.
Happy Hunting
Carpe Diem
 
Carpediem44DB said:
Its True! As I understand it, the boat manufacturers in the early 2000s wanted to build sexier faster boats but Cummins did not have a 500 HP engine to sell them so they just supped up the 480s a little and put bigger props on them for better top end performance with out regard for longevity. The QSCs were just a better thought out and engineered revision of the same engine and as such has had none of the issues that the 480CE line suffered. I love mine and have really had no issues in 450 hrs save for a harness fail and that had no effect on performance just instrumentation.
Happy Hunting
Carpe Diem
Click to expand...

great! Glad to hear they’ve been solid for you. I guess our search just expanded :)
 
Strecker25 said:
Hi all, we've been looking at 420DA's that mostly have the mechanical 6CTA's. Since the market is so thin, I've expanded to the newer 44DA's that mostly have the QSC500's. In my research up to this point it doesn't seem like these QSC's have the colored past of the 480CE and some others- is that true?

I know the basics apply: maintenance, WOT RPM and overload check, oil samples, etc, but are there are QSC gremlins or major known issues on this engine (specifically to the 44DA if that matters)?
Click to expand...

The QSC was a complete top down redesign and still in production today. As with any engine it needs to be propped correctly, Sea Ray had the 44DA with QSC's slightly over propped from the factory for heavy load conditions but not enough to cause any damage unless the previous owners ran it hard.

Like the 6CTA and 480CE the after coolers are the achilles heel of the QSC. Because of dissimilar metals the after coolers should be removed, pulled apart, cleaned, inspected, lubricated and reassembled every two years in salt water. If that service has not been done plan on possibly having to replace the after coolers as they weld themselves together pretty easily. New after coolers are around $3,500 each and even those need to be disassembled and lubed.

Because the QSC is electronically controlled there is a slight risk you will go into "guardian" mode if a sensor fails but that slight risk is well compensated in my view as they burn super clean with only the slightest hint of exhaust smell when temps are below 60.

Specifically on the 44DA the QSC is a great engine, the after coolers are very easy to access as are the water pumps.

Also with newer 44DA's you also get larger hull windows, an extra cabinet in the galley where the older models had the TV and slightly wider door leading into the v-berth.
 
Shaps said:
View attachment 89152
After about 3 hours in the ocean.
The more annoying part is the oil runs along the pan rail and drips in various spots.
Think I just answered my own question and will get it done, unless someone has a suggestion?? PLEASE!?!?
Click to expand...
Just a thought, but perhaps your breather air/oil separator needs cleaning. When it gets dirty the vented air flow is reduced causing higher crankcase pressure. the dip stick seal may be fine, it just cant handle the higher pressure. That is on my short list to do as well.
Carpe Diem
 
Agreed, ordered.. Thanks CD.
 
Carpediem44DB said:
I love mine and have really had no issues in 450 hrs save for a harness fail and that had no effect on performance just instrumentation.
Happy Hunting
Carpe Diem
Click to expand...

Hi Carpe Diem - I have the "No SIM J39 data" error message on Dieselview. I have had intermittent gauge issues for about 12 months... I just read on Seaboard Marine site that the Low Coolant sensor can leak and have coolant run into harness and sensors and down into the ECM causing these error codes and gauge issues. Did you experience that along with the "harness" comment you mentioned?
 
Last edited:
IMG_20200907_163149.jpg
Came back last night and went into ER to do my fresh water flush to find a small but noticeable amount of water in my now usually dry bilge. Look around and see that the input tube to the starboard heat exchanger had developed a pin hole right before one of the bends on the pipe.
Thank goodness for rescue tape!
That leads to a few questions:
Has anyone seen something like this?
Any thoughts how long I can run it with the rescue tape?
Pull it and weld it? Try to get it welded in place?
Or is there risk that another pinhole is around the corner and I should replace it.
 
Last edited:
Shaps said:
View attachment 91838 Came back last night and went into ER to do my fresh water flush to find a small but noticeable amount of water in my now usually dry bilge. Look around and see that the input tube to the starboard heat exchanger had developed a pin hole right before one of the bends on the pipe.
Thank goodness for rescue tape!
That leads to a few questions:
Has anyone seen something like this?
Any thoughts how long I can run it with the rescue tape?
Pull it and weld it? Try to get it welded in place?
Or is there risk that another pinhole is around the corner and I should replace it.
Click to expand...
It is so easy to remove and inspect the inside of the tube, I would not try welding in place. I would only weld it if it was determined to be just and inclusion in the metal and not from corrosion. Its probably not a cheap piece of pipe but replacement would be the best and safest option. I would only use the tape to get me back home.
Carpe Diem
 
villain style said:
Hi Carpe Diem - I have the "No SIM J39 data" error message on Dieselview. I have had intermittent gauge issues for about 12 months... I just read on Seaboard Marine site that the Low Coolant sensor can leak and have coolant run into harness and sensors and down into the ECM causing these error codes and gauge issues. Did you experience that along with the "harness" comment you mentioned?
Click to expand...
Short answer, no. I had no evidence of leaking. When I did my heat exchanger service and disconnected my port harness, upon reconnecting everything I had no temp or fuel level info on my smartcrap for the port side. I inspected, cleaned and lubed all the connections and could not correct the issue until I bent over and bought a replacement medusa from Seaboard. Has worked like a charm ever since. I have found that Corey and Tony know their stuff so I would probably go with their advice. (sorry for the delay in response, I don't know how I missed your post earlier)
Cheers
Carpe Diem
 
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