2006 F250 Overheat alarm while gauge showing normal operating temperature

[boscoe99]

I can see an engine heating up shortly after it has been turned off due to residual heat in the motor causing the temperature to rise. Letting the motor run for a bit of time (75 seconds or 25 seconds) should allow cooling water to bring the temperature down below the thermoswitch or thermosensor set point, to avoid a nuisance alarm. Assuming of course that the temperature rose to the set points of the switch/sensor in the first place.

[fairdeal]

The alarm should sound:

A. when a thermoswitch closes and (1) 75 seconds time has elapsed since the motor was started or (2) 25 seconds time has elapsed since the motor has been running above 2000 RPM

B. when the engine temperature is above 248* F and 75 seconds time has elapsed since the motor was started or (2) 25 seconds time has elapsed since the motor has been running above 2000 RPM

That reminded me - I have to do my income tax...

[boscoe99]

I heard that all we have to do now is to fill out a post card.

[fairdeal]

I heard that all we have to do now is to fill out a post card.

that would be nice.

I have read that some "developed countries" have a system where the taxing authority mails the taxpayer a card,

providing the government'scalculated tax amount.

The citizen is free to disagree and file claiming otherwise. But if you accept their number, no action necessary on your part.

I've also read that whenever such a system is suggested here, the DC lobbyists for H&R, Jackson Hewitt and TurboTax pull out all the stops....

[boscoe99]

that would be nice.

I have read that some "developed countries" have a system where the taxing authority mails the taxpayer a card,

providing the government'scalculated tax amount.

The citizen is free to disagree and file claiming otherwise. But if you accept their number, no action necessary on your part.

I've also read that whenever such a system is suggested here, the DC lobbyists for H&R, Jackson Hewitt and TurboTax pull out all the stops....

90% of all wage earners here in the US should not even have to get or submit a card. Just let the wage payers and interest/dividend payers send whatever taxes are owed directly to the IRS and leave the payee out of it.

But just getting a card to which a challenge could be submitted, or not, would be a great improvement.

Don't forget about all of the mindless IRS employees that should not be needed. Good luck getting the government employee's union to agree with getting rid of them as well. I suspect the union is funding lobbyists who are providing slush fund payments (in the form of campaign contributions) to our elected officials. The same ones we elect over and over and over.

[jol1ymon]

Update...swapped thermostats from port to starboard and ran motor on muffs again connected to YDS. This time I also ran water thru the flush adapter as well as the muffs. Engine temp only got up to about 140 this time and used a laser temp meter on both thermostat housings and only saw temps of about 110 on the sensors. Shut off the water to the flush adapter and kept water going thru muffs, and temp slowly rose to 155. The laser temp reading on the Starboard thermostat sensor rose to 175 within a few minutes, Port side still around 110 on the laser. Turned the water back on to the flush adapter and the overall temp via YDS fell back to the 140-145 range, and the laser temp sensor on the Starboard thermostat almost immediately fell back to 110. I know at one time I had a blockage in the motor which I fixed with the acid flush. It appears that I chased my tail a bit thinking that it was overheating, or had faulty sensors when the only real problem was a lack of waterflow from running on the muffs. Going to water test it this weekend after finishing replacing some leaky trim seals. Have a pretty good feeling that it is going to operate as normal. Thanks for the help, will confirm my success or failure after an in-water test.

[jol1ymon]

Possible Oil Control Valve Problem????? Reminder 2006 LF250TUR Launched the boat last weekend to see if overheating issue was solved. Once I got on plane I had quite a bit of surging in RPM's and could not get to WOT of 5700 RPM, and again got an overheat alarm with the temperature gauge showing in the middle. Just prior to launching I replaced the fuel filter before the engine. Drained the VST which produced some small debris and water and tried again. (VST rebuilt with all new filters 100 hours ago) This time the surging was reduced, but still there, and still no WOT capability. Changed Spark plugs (100 hours on them), and they all looked pretty equal. Drained VST again and ran the boat again. Surging stopped, and able to reach WOT, but still overheating and going into limp mode without the gauge showing hot. Hooked up YDS back at dock and engine operating at idle at 157 degrees, with no faults registered. Did stationary test of Injectors and they are all operating. Then tested Oil Control Valve...the port one made an audible sound. Went to test the Starboard and no sound. This is the same side that the thermoswitch (which I tested and is operating within specs) was getting triggered running on the hose. Tried the Port again, and could hear it. Starboard again and no sound. Tried the Starboard a third time, and now I can hear a very faint noise coming from it during the test, but not nearly as loud as the port side. Repeated multiple times and still just faint. What does this do? Could it cause the Starboard side to get hotter than the port (which is where the Command Link gauge sensor is located), causing the starboard thermosensor to trigger an overheat and limp mode to kick in? This is driving me crazy....Thanks for your help!

[jol1ymon]

Checked the Starboard Oil Control Valve and it is operating within specs of the Yamaha Manual. Cleaned the filter on it as well. Ran boat again yesterday for a few hours, and I was fine as long as I kept the rpm's at 4200--4400. Towards the end of the day, I raised the RPMs up to about 5100, (5700 is WOT) and got same overheat alarm and limp mode, while temp gauge still showing in middle. As long as I shut the engine off to reset the alarm, I can start it right back up and temp gauge is in middle and continue on my way at RPM's in the low 4000's. Any other ideas on where I should go with this one? Please?

[99yam40]

What Yamaha has said about the criteria for the over temperature alarm being set is confusing, depending upon what document one is reading. No surprise there.

The alarm should sound:

A. when a thermoswitch closes and (1) 75 seconds time has elapsed since the motor was started or (2) 25 seconds time has elapsed since the motor has been running above 2000 RPM

B. when the engine temperature is above 248* F and 75 seconds time has elapsed since the motor was started or (2) 25 seconds time has elapsed since the motor has been running above 2000 RPM

I guess the A scenario is what is getting the alarm to sound.
have you made sure which switch is closing?
and have you tested it in a pot of water while you heated it to see what temp is closes at?

Maybe a Rydlyme descaler flush might help

[pstephens46]

Reads as if you have several issues. I may have missed it, but have you disassembled and cleaned the VST filter? Draining it doesn't do much other than tell you it may be dirty. Finding a piece of O-ring could mean there is more stuff in there creating a water restriction in regards to overheating. Assuming the water pump was assembled correctly.

[jol1ymon]

I determined that it is the starboard thermoswitch. I have tested the thermoswitch in a pot of water, and it is working within specs. I ran a solution of Barnacle Buster (phosphoric acid) thru the motor for 4 hours a few weeks ago with a submersible pump to descale the motor. Pulled rear exhaust jackets off and inside looked really clean after, as well as the inside cavities where the head zincs reside, also clean inside thermostat housings. Thats not to say that there still may be a blockage somewhere. Considering running another descaling flush with vinegar maybe. The waterpump is all new and I am pretty confident there is no issue with that, as I have done it over a dozen times over the years. I plan on cleaning out the VST again once I get it back out of the water today, did not want to attempt that at the dock. I did go thru the VST tank last year, less than 100 hours ago and replaced all of the filters. That is not to say they could not be blocked again. Strange thing is that I get the overheat when the motor temperature guage reads normal. I understand that the temp gauge is not what triggers the alarm, as it is the thermoswitches that do that function. I am stumped at what to do next.... I fear my next step is to pull the head, but I am really hesitant to do this on a four stroke. If it were my old OX66, I would have yanked it already, but I fear the extra complications of the 4 stroke. Thanks for the help!

[99yam40]

I had to re read some of this.
I have no idea how the oil control valve sets an alarm on this 4 stroke motor.

I think it changes the timing of cam with oil pressure as pressure rises
I have no idea how to test to make sure it does what it should, maybe manual has info.

Draining VST and finding water and debris is not good

only motor I played with that overheated at higher RPMs was a 2 stroke. water pump and stat did not help it.
so I pulled lower hooked a water hose to the pipe going up to block, pulled stat , shot water full blast up thru motor and shot compressed air into the water hose in bursts to try and move junk around in motor.
ran well after putting all back together.
my guess was there was debris in places restricting water flow that got dislodged and out when flushing

[rodbolt17]

my guess would to use YDS properly.
if it stored an overtemp code then the ECU agrees with the thermoswithcs.
however if just a switch cloeses and the sensor does not agree it wont store a code.
YDS will tell you if a switch is open or closed. it wil also tell you where the intake cam is. is it retarded or advanced and how many degrees.sometimes,just like the OX66 you must be operating it at the time of the alarm. may not even be an overtemp.
YDS will store the last 13 min of operation and it can be saved and printed out.
if you run it and get an alarm the diagnoses screen will highlight it as long as it is active.
but that is just how I would do it.

[jol1ymon]

Thanks Rodbolt...never had a stored code with YDS, but don't think I have checked within 13 min of actual running. I have watched YDS change a thermoswitch from open to closed and trigger the overheat alarm, but never tried it while on an in-water test. Going to do one more acid flush, and re-test both thermoswitches and thermostats, inspect my newly installed waterpump to make sure all is good there. Next in water test, I will take the laptop with me. Do you recommend running the boat with YDS attached and monitoring motor while I instigate an overheat warning, or attach it just after the overheat and check data then?

In response to 99yam40...have already attached hose to uptube and compressed air to other end...spent an entire day doing this. Did get some debris this way...did acid flush after that. That being said...not a bad idea to do this again -post the last acid flush and maybe even after the next acid flush. I am considering using vinegar, or possibly Rydlime, but have read something about the Rydlime being fairly corrosive to aluminum. Also seen a product called Hammerhead which states it is safe for aluminum. Any opinions? At the end of the day, I guess I would rather use something that will actually eat away at a blockage, rather than something that is completely safe, but does not actually remove anything. Any advice on what to use would be highly appreciated from anybody though. I REALLY REALLY appreciate all of the help with this from everybody!!!

[rodbolt17]

myself?
I would monitor the engine screen and see if both cams are close. then shift to the diagnoses screen and see what pops up as irregular and if I got an alarm I would hit the save button.
that will create a permanent file for that cycle. then you can switch back to the monitor screen and see if a thermoswitch is closed.you can do it either way.
either way it highlights the problem that triggered the alarm.
the OCV's wont trigger an alarm but the motor will be a sluggish beat at mid range.