3116 smoke haze

Two Tides

New Member
Feb 10, 2017
7
Puget Sound
Boat Info
1997 370 Sundancer
Engines
Twin 3116's
I have a 1997 370 Sundancer twin 3116's with 850 hours on it (I have put about 35-40 hrs on it since I bought it in January). While under way I have a faint "smokey haze" black/brown in color over the water. Not able to capture in a photo but can see from the boat. This seams to be coming from the underwater exhaust since I do not see it from the side by pass. I typically run at 1900-2100 rpm 60-65% WOT. I also will run low at about 1500 if towing my dinghy - no longer than an hour and a half. And after I tow it I will run it up around 2200 to burn off any carbon. Temps are from 175-190, and oil psi is right around 50.

My question - do any other CAT owners experience this? If so what have you done?


Again the boat runs amazing! Just don't want to be missing tell tell signs of a problem.
 
I did last year. I had a faint brownish smoke on the horizon off the stern. I cleaned both after coolers and problem gone. The side exhaust outlets are staying a lot cleaner also.
 
Thanks for the input! I got this input also about oil type - since I am pulling the boat out Tuesday for a new davit and oil change, and showed him my oil samples from my survey

Looks like the form says it is multi weight, so that is probably the source of the smoke if that's accurate. The SAEO oil from Cat will prevent that, it's specially formulated to remove the sooting you are seeing.
 
Rotella 30W is acceptable also.
Another contributor besides restricted aftercooler flow are dirty air filters.
Did your oil samples show high soot? If so - Is the boat hull below water line and running gear clean? Can you get 2800 to 3000 RPM at full load?
If you cannot achieve at least 2800 RPM at full throttle the engine is over-fueling and that unburnt fuel will end up as soot and can be seen in the oil samples, along the boat sides and in the water. Many of our boats of this era were a bit over propped not allowing the correct full load engine RPM's; I ended up taking 1.25 inches out of the props to get the correct engine loading; this brought the soot in the oil into spec and ended the mess on the boat sides and swim platform.
 
Soot on both engines was 0.3 I would post the pictures of the sample but don't know how on an iPhone.
Boat had bottom paint and everything cleaned in January. At sea trial in December was able to achieve 2875 on port and 2825 on starboard. 36.2 mph. I do get some soot on the sides not the swim step but it is noticeable. Looks like and oil change, filters and aftercooler cleaning are in order
Thanks for the insight
 
did you clean your after coolers? Or have it done?
If you did, how?
I removed them myself and installed them myself. I gave them to a shop to clean. +1 on the Rotella straight weight and that is coming from a certified Cat shop.
 
Thanks for the input! I got this input also about oil type - since I am pulling the boat out Tuesday for a new davit and oil change, and showed him my oil samples from my survey

Looks like the form says it is multi weight, so that is probably the source of the smoke if that's accurate. The SAEO oil from Cat will prevent that, it's specially formulated to remove the sooting you are seeing.



Just changing to Cat SAEO or Rotella T SAE 30 or 40 by itself isn't going to solve your transom sooting/smoke problem.

Single Viscosity oil doesn't have viscosity enhancers in it like 15W 40 does. The viscosity enhancers have been show to cause aftercooler fouling on the when they form deposits in the intke air side of the aftercooler. Restricted intake air is one cause of sooting, and as Tom says, dirty air cleaners can also cause sooting. After cleaning the aftercoolers, you should switch to SAEO or SAE 30 or 40 depending upon your ambient tempertures. That will stop the deposits from forming in the aftercooler, but just changing the oil will not stop the sooting.
 
Thanks for the additional info Frank, I just went to the CAT dealer down the road and picked up 14 gallons of SAE 30, And new filters.

Am I in for a big expense in getting the after coolers cleaned? I know it's a boat and a lot but just want to prepare myself ...

I have as people say they use fuel treatments like ValvTect. Should I look at using this also? Or do you recommend something different.
 
0.3 on soot is within range however much is determinate on engine hours with that oil; soot is accumulated so, for example, 0.3 with 20 hours on that oil change will probably be high.

The aftercoolers are easy to remove and install; just get new gaskets and make sure the bolts are cross torqued when reinstalled. For the 3116 engines the aftercoolers are jacketed with the engine coolant (antifreeze) so drain down a bit the engine's coolant before taking off the hoses. Our local marine service shop cleaned my aftercoolers; I believe they were $120 each and gaskets were around $40. I used high heat spray paint on the external surfaces which was around $8 and new hoses was another $50 or so.
 
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0.3 on soot is within range however much is determinate on engine hours with that oil; soot is accumulated so, for example, 0.3 with 20 hours on that oil change will probably be high.

The aftercoolers are easy to remove and install; just get new gaskets and make sure the bolts are cross torqued when reinstalled. For the 3116 engines the aftercoolers are jacketed with the engine coolant (antifreeze) so drain down a bit the engine's coolant before taking off the hoses. Our local marine service shop cleaned my aftercoolers; I believe they were $120 each and gaskets were around $40. I used high heat spray paint on the external surfaces which was around $8 and new hoses was another $50 or so.
I'm looking to do this on mine, I just can't take the sootiness on the transom (and seats and canvas and hard top and...), but have no idea where to start. I'm OK with doing maintenance on things, as long as I know what I'm looking for. I assume the after coolers are just downstream of the turbos? Which parts are you talking about for replacing from here: https://parts.cat.com/AjaxCATPartLo...W94rnIA==&storeId=21801&serialNumber=4KG07844 I assume it's #4, anything else to look for? Do you know where to find the torque specs? I think I have Cat manuals on the boat, I'll go get them from the marina and see if it shows any of that in detail. Just thought I would ask here to get advice. Sorry for the basic questions, but this is my first diesel boat, so I'm still learning. A ton. :)

Kevin
 
If I recall when I did my aftercoolers they were easy to get off and I took them to a radiator shop to get them cleaned what cost about $100 for both. I put new gaskets, new turbo charger hose and replaced the cooling hoses under the cooler as they were easy to get to with it off. I think all the parts were about $200. So it's about a $300 job if you do it yourself. At least five years ago in Alabama.
Good luck.
 

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