3116 running 15 hotter than other?

EKM

EKM

Active Member
Feb 4, 2007
674
Beach Haven, NJ
Boat Info
2000 420AC
Engines
Cummins 6CTA
Hi all,
Boats in the water for the season and during my short voyage to my marina (30 min), the starboard runs 180 and the port runs 165. In looking at the engines, the stbd coolant overflow tank has a leak (can this be fixed or replaced?) and the stbd turbo has a slight oil weep as you can see a small amount of oil on the turbo case. Does a small leak foul the intercooler to make the engine run hotter? Does the turbo need to be rebuilt? I replaced the water pump impellers in 2007 but have not inspected the heat exhanger.

I had knee surgery March so not very flexible to jump into the engine room. Has anyone figured out how to install a ladder to ease the trip into the ER?

Anyway, boat runs great after hibernation period required in the North country....looking forward to paying 3.80/gal for fuel.
Regards,
Ed
 
My 3126 motors both run dead on at 180 when on plane. They usually run at 165 before I come to plane and cool back off to about 165-170 when I come back off plane. Sounds to me like your port motor is running cool.....maybe a stuck (open) thermostat.

The overflow tank can be repaired, depending on where the leak is, with some good epoxy. But, I would probably just replace it....

As to the Turbo oil leak....Oh Mr. Webster!!!....you out there????
 
I suggest you purchase a heat/laser gun just to make sure your gauges are true. Under $50 and a great tool to keep on the boat...lots of fun at parties.
 
As I passed by the fuel dock in Beach Haven NJ (Polly's), I was almost excited at $3.80 since I was expecting worse. Two week ago it was $3.60/g. Anytime I cruise, I try to end up pretty empty to fill up here.

So tank can be fixed with a little epoxy.

I probably need to take the ends of the heat exhanger at some point just to check it out but I need to get my knee to work a little better. I even had to pay the marina to wax the boat...first time I have ever gone this route. If it ended up with a nice wax job, I would try it again, but the job was not to my expections.

BTW, impressed on how fast the diesel started after the winter dry dock...just like starting in the summer...it seemed like one crank revolution and they are running. NICE!!!
Regards from NJ (still cold up here)...Ed
 
mrsrobinson said:
I suggest you purchase a heat/laser gun just to make sure your gauges are true. Under $50 and a great tool to keep on the boat...lots of fun at parties.
Click to expand...

This is a great idea- gotta get me one.
Confirming the higher temp is first step- I assume there are no separate, engine-mounted gauges for you to compare the readings?

My 3208's run 180 as long as the water temp is cool- 70 or below. When we get up into the 80's they run close to 200. Cat tells me no problem with that, but I've never been comfortable being that close to the "edge". I flushed the raw water side of the engines with a de-scaler called Rydlyme last weekend, and after looking at what came out I'm hoping for cooler running. After I get a chance to get out and run her I'll post the results.
 
I had both of my thermostats replaced last year when I did a coolant flush and replacement. The ones that came in, direct from Cummins, were two different styles/manufacturers even though they were both rated for the same temp (160 degrees I believe). Because of the different styles, one engine ran 10 degrees warmer than the other and heated up in a different pattern and it just drove me nuts so I replaced it so both engines had the same temperature and rise in temperature.

I'm not saying that is your issue at all. Clogged heat exchangers (oil being blown in from the turbo charger leak?) and many other things can cause a difference.
 
I'm not going to be much help on this one since all this will do is raise more questions.

3116's have 195 degree thermostats in them and they should run right on 195 degrees because the cooling system is so over designed that you have enough capacity to keep the engine from running hot even with some minor fouling of heat exchangers, etc. I would verify the temp as others have recommended and go from there. However, you need to find out why you are not running at the thermostat's limits on both engines. I tend to suspect old coolant and stuck thermostats, but that is a WAG from 2000 miles away.

Turbos shouldn't leak anything. My engines are perfectly clean and leak nothing and I'm at 1000 hours, 12 years old. Depending upon the year, there was a turbo recall on 3116's in about 1996-7, so you might want to involve Caterpillar on this one.
 
fwebster said:
I'm not going to be much help on this one since all this will do is raise more questions.

3116's have 195 degree thermostats in them and they should run right on 195 degrees because the cooling system is so over designed that you have enough capacity to keep the engine from running hot even with some minor fouling of heat exchangers, etc. I would verify the temp as others have recommended and go from there. However, you need to find out why you are not running at the thermostat's limits on both engines. I tend to suspect old coolant and stuck thermostats, but that is a WAG from 2000 miles away.

Turbos shouldn't leak anything. My engines are perfectly clean and leak nothing and I'm at 1000 hours, 12 years old. Depending upon the year, there was a turbo recall on 3116's in about 1996-7, so you might want to involve Caterpillar on this one.
Click to expand...

Our friends 1997 400DA with 3116s had a turbo leak...this may explain it now.

I spoke with one of the best CAT techs/surveyors in Florida a few weeks ago about the 3116s and Frank is spot on with his remarks.
 
Thanks for the suggestions....I was looking for reasons of running hotter but maybe it could be Tstat stuck for running cold? How often do you replace coolant? Is this the same as Cat Truck Coolant or marine only?

Would cat still cover a 12 year old turbo for recall? Is it a problem running with a small leak like this or is it worth a new cartridge?
Thanks....still 55F outside. Summer weather needs to get here soon.
 
Sorry about the knee Ed. Check out my recent thread about changing coolant.. As suggested on the forum I recently replaced the coolant in both engines with pre-diluted Cat ELC, 8 gal./engine. There were no problems, I just wanted to know that the coolant was clean and effective. I also didn't know what was in there. The ELC has all of the rated additives (see maint. manual) and is rated for around 6000 hrs so I should be done for awhile. (Also just changed transmission ATF and cleaned the filters too so all fluids are done!)
Cheers,
Warren
 
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