Ford V-10 Techs Needed, Diagnos My Erratic Coolant Temp

[timmac]

OK I just went on a short trip out of town on my 08 Bounder Ford V-10, went to Laughlin NV and on the way back up that very steep climb out of Laughlin my trans was searching for gears since I was pulling my Jeep and Boat I decided to put the trans in 3rd on the shifter column and just cruise at 45-50 mph up the hill at about 4500 rpm's, I have never locked the trans in 3rd gear before just decided to try it today and about 4 to 5 minutes up the hill a beeping noise was coming from my dash says check gauges and my engine temp was at max in the red zone, as I slowed downed I shifted trans back into the drive selection and as RPMs went down the temp gauge moved back to the normal range in 1 second, yes it went from max hot to normal temp that fast, I dont know how fast it climb in temp did not notice that part.

So what the heck happen, I did drain my radator about 2 months ago and did test drive than but this was the 1st time out since fluid changes, I did check my radator fluid level at the next stop after this happened and all was fine and as far as I could tell my motor was never hot but the gauge said max hot.

So did running in 3rd gear do this OR did I have a air pocket stuck in the cooling system or what..

Yes its strange what happen but I have never seen a motor cool off in 1 second.

:C

[doxiemom11]

I didn't know you were ever supposed to use overdrive when climbing, and have always heard that keeping your rpm's down also will help keep the engine and transmission cooler. I think you will kill your engine/transmission if you keep pushing it that hard when you climb. Why do you think they always say - sit back in your seat, relax and enjoy the climb.

[PUCampin]

Most likely causes have been addressed already, I just want to add that locking into a lower gear and crusing the hill at a higher rpm like you did is the BEST thing you can do in that situation. The higher rpm circulates coolant faster, runs the fan faster, and keeps the engine in the fat part of the powerband. Locking in 3rd keeps the trans from hunting and has a better chance of keeping the torque converter locked. The modular Ford engines are all overhead cam and designed to run.

I have pulled numerous long grades here in CA including Towne pass East in Death Valley from Stovepipe Wells at sea level to the summit at 4955ft in around 16.5miles. Average grade is 5.6 percent with a max around 9 percent, but once you start is one loooooong pull! Once the Expy downshifts I manually select the gear to hold it as long as necessary, or I will sometimes manually downshift before the computer wants to. If I downshift I always lift off the throttle for the shift.

[theoldwizard1]

timmac wrote:
... I am also thinking the cooling system might have had a air bubble ...

Most Ford cooling systems use what is called a remote coolant reservoir. This is NOT and "overflow" tank ! This is a pressurized tank (usually see through plastic) that is part of the cooling system. By design, the tank is the highest point in the system. This means it is nearly impossible to get an air bubble in the system.

Even after completely draining all of the coolant out of a Ford, refilling and a few heat/cool cycles will force any air into this tank. There are low and high marks on the outside. Even though the cap does not look like a normal radiator cap, it is a pressure cap and you do NOT want to open it when hot !

[John_Wayne]

Invest in a Scan Gauge II and get the actuall readings and you can get the trans. temp reading also plus a whole lot more.

[timmac]

dodge guy wrote:
I agree, sounds like its sticking! But am I the only one that read "since I was pulling my Jeep and Boat"? I know the V-10 is a workhorse and will do almost whatever you want it too, but That is asking a lot of it! Especially in the heat!

It was only 80 degrees outside and my total weight pulling is 26,500 lbs, been all over the place in hotter temps and never a issue.

[timmac]

Well I did not change my theromstat when I flushed my system maybe I should have done that as well, I am also thinking the cooling system might have had a air bubble or the Ford sudden temp change issue as posted on this forum.


And yes my fan clutch works good and my total setup weight with open stacker trailer carrying Jeep and small boat is 26,500 lbs,


The temps for that day was only 80 degrees.

[camperdave]

I recently had that almost exact thing happen on my little 4 banger Nissan Frontier! Heading up a moderate hill at high revs (unloaded, it's not my tow vehicle or anything), and then sudden and complete overheat into the red to the point of immediate concern. In my case I quickly turned on the heater and slowed down, and within 20 seconds the temp was normal again. I wrote it off as an air pocket, surmising that the change of flow pattern with the heater core now engaged freed up the bubble. To be safe I did change the hoses and put in a new T-stat after that happened, as it's a 2000 on all original parts.

[rockhillmanor]

Did you ever hear the fan clutch come on? If not I'd check it.

You can't miss it. On a V-10 when that fan clutch engages it sounds like a jet engine firing up!

First time I ever heard mine was climbing a grade and I had no idea what that sound was, never heard anything like it on a vehicle. It was LOUD!

[theoldwizard1]

SidecarFlip wrote:
Sounds to me like the sudden max temp was caused by cavitation around the probe and when you dropped the rpm the cavitation ceased and the temp dropped to the normal range.

This is my guess also !

If you had dropped the RPM down to abut 4000 or less in 3rd gear, I will bet the temp would have dropped just as quickly.

[SidecarFlip]

Sounds to me like the sudden max temp was caused by cavitation around the probe and when you dropped the rpm the cavitation ceased and the temp dropped to the normal range. First thing I'd do is flush the entire system, replace the radiator cap (in fact I replace mine every other oil change because the spring inside gets weak and won't hold static pressure and caps are CHEAP and I'd install a real temp gauge not the OEM one.

One of the most neglected things on any tow vehicle (besides the transmission fluid) is the radiator cap.

[carringb]

There's no reason 4500 RPM will cause overheating. It's designed to run that fast. I do it, and much faster, for extended pulls up long grades.

Since you recently had cooling system work done, I'd be suspicious of an air pocket. If that's the case, it probably purged itself. If it does it again, I agree with swapping the T-stat.

[dodge_guy]

I agree, sounds like its sticking! But am I the only one that read "since I was pulling my Jeep and Boat"? I know the V-10 is a workhorse and will do almost whatever you want it too, but That is asking a lot of it! Especially in the heat!

[garyemunson]

10 year old motor...needs new thermostat. Sticking.

[timmac]

Will Ford pay for their mistake or am I stuck with this repair, found this on another site, my chassis is a 2007.

TSB
06-21-15 MIL ON - DTC P1285 / P1299 - 5.4L 3V / 6.8L 3V - FALSE OVERHEAT

Publication Date: October 13, 2006

FORD: 2005-2007 F-53 Motorhome Chassis, F-Super Duty



ISSUE:
Some 2005-2007 F-Super Duty and F-53 Motorhome chassis vehicles equipped with a 5.4L or 6.8L 3-valve engine may exhibit an engine temperature gauge indicating an overheating condition with the malfunction indicator lamp (MIL) on with diagnostic trouble codes (DTCs) P1285 and P1299.

ACTION:
Performing normal engine cooling system diagnostics in Workshop Manual, Section 303-03, if it is determined that the engine is not physically overheating (coolant expulsion), install a new thermostat and crossover pipe. They have been revised for improved cooling system flow characteristics.


PART NUMBER PART NAME
7L3Z-8575-A Thermostat - 5.4L
7C3Z-8575-A Thermostat - 6.8L
3L3Z-8C368-A Crossover Pipe - 5.4L
3L3Z-8C368-B Crossover Pipe - 6.8L


WARRANTY STATUS:
Eligible Under Provisions Of New Vehicle Limited Warranty Coverage
Note: Normal would be from 190 to about 220. The actual boiling point of the system is about 262. 212 water+5 for coolant +15x3 for cap pressure =262.

http://www.irv2.com/forums/f23/false-overheat-tsb-50007.html

[timmac]

And here's another same issue I had today, appears I was not seeing things after all.

06-21-15***MIL ON - DTC P1285 / P1299 - 5.4L 3V / 6.8L 3V - FALSE OVERHEAT

$1000 repair to fix the issue and by the post on the link below its not really overheating just a false reading..



https://www.ford-trucks.com/forums/1136411-tsb-06-21-15-new-thermostat-and-crossover-pipe.html