3126 running temp

[joelucci33]

So Im running a steady 208 temp under load in the 3126 (300 hp model)..book call for 195...any ideas on what could be causing the 10 degree difference?

 

[steveinak]

Buddy of mine had a similar problem, it turned out when he turned on the gauge lights the temp gauge would go up 10 degrees ???
Have you cleaned out the aftercooler and turbo lately ? Clean bottom? I had a pyrometer on my old boat and when it started to grow grass and slime up on the bottom the pyro would go up 10-15 degrees. The old boat had a 41 volvo in it and when the raw water pump was worn/bad impellor the temp would climb. Maybe you have some broken off impellor pieces blocking the raw water flow ??

 

[joelucci33]

Buddy of mine had a similar problem, it turned out when he turned on the gauge lights the temp gauge would go up 10 degrees ???
Have you cleaned out the aftercooler and turbo lately ? Clean bottom? I had a pyrometer on my old boat and when it started to grow grass and slime up on the bottom the pyro would go up 10-15 degrees. The old boat had a 41 volvo in it and when the raw water pump was worn/bad impellor the temp would climb. Maybe you have some broken off impellor pieces blocking the raw water flow ??

Steve,

Brandy new Impeler...Brandy new CAT turbo...after cooler cleaned boiled etc..

I havent jumped in the water to check the strainer yet...but Im getting awesome water pressure..50 PSI under load.

 

[traditions]

have you had any old impellers chewed up in the past?Those pieces of the impeller usually go some where and stay,as do old zincs.I would want to check with a mechenical gauge first,could be a sending unit,of faulty gauge.I had one that when you tapped on it,it would drop 10 degrees

 

[steveinak]

Steve,

Brandy new Impeler...Brandy new CAT turbo...after cooler cleaned boiled etc..

I havent jumped in the water to check the strainer yet...but Im getting awesome water pressure..50 PSI under load.

You have a gauge for water pressure ?

 

[joelucci33]

Yes we have a water pressure gauge

 

[Blitzen]

Has your heat exchanger been cleaned? It may look clean but a film of zinc and calcium will decrease the efficiency of the cooler enough to raise your temps. I had this problem on my 300hp 3116. Cleaned the cooler, new thermostat and it was running 195 all day long.

 

[Blitzen]

Also what coolant are you using and are you sure it is at the proper dilution if not using ELC from Cat?

 

[Nighthawk]

It's always good to know the real temperature versus indicated by a voltmeter at the dash. Once you determine that you really are above spec then I would follow Blitzen's advice and clean coolers. A Rydlyme flush for example will most definately drop your temps back if any coolers are coated with highly insullating mineral scale. It has amazed me several times that a seemingly clean cooler can become much more efficient with a descaler treatment like Rydlyme, Barnacle Buster etc. Punching out a cooler is fine for shell pieces and general debris but it's the coating that you can't really see that typically causes the problem.

 

[Tuna Pursuit]

It could be electrical. My cummins will run at about 200(should be 180)when the batteries are low. As the batteries charge the temp goes down.

 

[captainlarry84]

I think the key is to run the boat at WOT. If the temps creep up then the heat exchanger is not doing it job and it needs to be clean. I just did my 370 Yanmar with a reverse flush. Rydlyme. It was quick & easy to do. The results were amazing… plus no dismantling of motor parts.
I always run my boat @ WOT and the beginning & end of every trip. That is how I picked up on the thermal creeping of the motor. After the cleaning WOT and the temp stays @ 180 degrees with zero gauge movement. I also did remove the exchange end cap and found some broken zincs.

 

[Tuna Pursuit]

totaly agree with the WOT although I don't do it every trip, only every couple of weeks on the way in. Good way to head off problems.

 

[pointblank1]

I have 3126 with 385HP. My temp creep was due to dirty/barnacled up Heat exchanger. Muriatic acid flush several times in a 5 gal bucket works great.

I also have a alternate set of mechanical gauges that are more reliable than electrical.

 

[joelucci33]

So quick run down for everyone..

3 weeks ago headed out..about 1 mile from the destination notice waterpressure guage jumping up and down...being cautious turn her around head back in...(we were due for an oil change and a good cleaning so we figured good day to get that done and investigate the issue)

Half way in..engine quits..steam out the exhaust.."ohh Fuck" common phrase used about that time!...take a looksey...water coming out the dip stick tube...close the Seacock...Call Towboat.

Get it in..do some research...either a failer after cooler or the seal around the shaft for the water pump...Removed both units. Seal was on the water pump shaft was toast. brought the after cooler down to thermoflo in watertown...had it cleaned tested etc...checked out perfect. Replaced the seal on the water pump..put her all back together...few oil changes to flush out the system...she was eatin up oil...called around ask some questions..."check your turbo..might have seen some damage when that seal let the water into the oil system"...yanked the turbo off...what a bitch!..yup turbos toast...Get a brandy new on from CAT..slap it back in...fresh oil..fire it up...Honestly runs great sounds great...bruning no oil at all.

Take her out for a run...idling up river..steady temp of 175...get past the no wakes put her under a load...I run it at 2500 for cruising...temp climbs to about 208...Just under the 210 mark on my gauge. Holds steady at 208....brought it up to 2600...still holding steady at 208.

I run all the CAT recommended fluids...Cat 30W SAEO...CAT ELC...We are anal about maintenance on the boat..

So thats were we stand now..

 

[WoundUpMarine]

Id check all your ground and other connection on the sensor and on the gauge panel, my isuzu was running about 10 degrees hot, and staying there, same as your, couldnt figure it out. turned out to be the ground on the temp gauges, just reading high. Use a thermal gun to check your expansion tank/engine, see if she is really 208 or if its just the gauge.

 

[Rearmount]

Also what coolant are you using and are you sure it is at the proper dilution if not using ELC from Cat?

I second the coolant advice.

 

[Rearmount]

Come to think of it, I ran a boat that had triple 3406's in her. Because of new design / regulations, the run temp was supposed to be over 200 degrees.

 

[reelsportfishing]

50lbs seems like alot of pressure for a raw water system that is an open loop . I would start pulling apart your raw water system starting right after the pump discharge. You may have chunks of old impeller, zincs or weed. You may have lost your sea strainer screen on the outside of the hull. It happened to me before. The whole raw water side was plugged with seaweed. If there is a blockage the first place to look would be your first cooler after the pump discharge. On mine it was the gear/fuel cooler. Good luck. Good exercise in learning your new engine.

 

[joelucci33]

I second the coolant advice.

I run ELC from CAT....Only Run CAT fluids in it

All taken into consideration...going to take out the thermal gun hopefully tonight and try to get a more accurate reading on the temp.

 

[GLA]

my 3176 shows 201 on the electric dash read out.

there is a plug in temp guage on the block that reads 193 to 195

so I believe there is a problem with the electric gauge, maybe you have the same problem.