Running Hot(er)

[Rip]

The 1505 engine in my F-3680 (3000 hrs) running hotter than it used to with new t-stat, cap, clean rad, coolant, oil & fuel filters, etc. Not really 'over heating' as such, but concerned. Runs well with good power but wondering about injector timing/spray pattern (have no experience with injectors)? Wondering if any had similar experience with this engine & problem?
Have another 1105 engine in similar machine (2000 hrs) and at idle it shows about 30 deg F cooler block and rad tank (per infrared temp gun) than the 1505 under same conditions. Dash temp gauge also about 30% vs 45% on the 1505 engine at warm idle.
Cheers, Rip

 

[RBsingl]

I have seen water pump impellers in other applications losing effectiveness due to wear with higher operating hours. Water pumps don't just fail because of seal or bearing issues, the impeller can also wear with age resulting in less circulation.

It is also worth checking the hoses. It isn't common but the interior can delaminate reducing flow rate.

Rodger

 

[Rip]

Water pump looks to have been replaced once on this (second-third hand) used machine, so probably not as old as rest. Top hose looked fine when I replaced the t-stat and cap, and no indications of corrosion or sludge when flushed and replaced coolant.... but have not had radiator internally cleaned.... exterior fins and all quite clean.

I know ignition timing or lean mixture on gas engines can make them run hot, so figure could happen to diesel as well.... just have no experience with that side of them.

 

[Dman1981]

Yes if a diesel is running lean can cause some overheating

 

[Rip]

Is what I thought.... may find someone with more diesel experience to look over my shoulder if I pull them.... there is a local injector shop that can test them. May do bit more radiator check and clean first though.

 

[Russian]

I just fought all of the similar issues on an F3060. Have you changed your pump/alt v-belt?

 

[Rip]

Belt is tight and in good condition (is also a real pain to change!)

 

[RBsingl]

Diesels don't run lean in the sense the term is used for spark ignition gas engines, they aren't like gas engines where a lean mixture results in hotter combustion. At a "lean" mixture, diesel engines run extremely cool.

At idle and at very low load, a diesel is typically operating in the range of 60:1 air to fuel ratio. This results in very cool combustion compared to the around 18:1 it drops to under high load. Too much fuel in a diesel is what increases combustion temperature, excessive EGT, and high soot output from incomplete combustion.

A diesel engine doesn't have a throttle plate (with the exception of some of the new Tier IV complaint where intake air is restricted during DPF regeneration to build more heat), isn't held within a narrow range of fuel/air mixture like a gas engine, and with less fuel injected it will generate less combustion heat.

At idle and with low operating load a diesel engine runs an extremely low fuel to air ratio, that ratio increases rapidly under heavy load. Diesel engine EGT goes up rapidly with very high fuel to air ratio.

Rodger

 

[Rip]

Thanks for the diesel details Rodger.... I knew was not same as for a gas engine, but the service manual does mention injector timing as potential issue for overheating. I guess individual injector problem would be more of a power issue (not in my case). After giving the cooling system bit more of a lookover, may still have to get a more diesel savvy person to take a look.

 

[CalG]

The question is oil temperature.

Above about 229 degrees F oil starts calling it a daay.

Anything below about 205 is good