2007 FG140 Overheating

[HD.Adventuring]

Hey Folks,

Over the past few weeks, my wife and I assisted Allan at Overlander Global in installing our composite box onto our 2007 Fuso 4x4. We bought the chassis last year with only 48k miles on it from a wildland firefighting company, and replaced the oil in engine, Tcase, trans, and diffs. Engine had no codes or issues when we bought it. Fast forward to this week, and after installing the box(which we're thrilled with!) and driving the truck home, it started to overheat on the mountain passes, and even on some of the flats. Outside temp was in the mid 90's. Elevations in the 7-9k foot range, so I understand conditions are ripe for overheating. Keeping the truck near the redline has helped the situation by spinning the fan at max, but we found ourselves needing to stop and let it cool off at a high idle before continuing. I blocked the EGR to test out if this helps, but doesn't seem to make a difference. Coolant looks OK, fan seems to be moving air, and under normal conditions truck warms up and stays at specific point on temp gauge, making me think thermostat is functioning.

I put my cheap bluetooth code reader on it, and got these two codes:

P0251
P0A00

Allan has mentioned some other 2007 trucks he's seen have also had cooling issues. Been searching this site, and haven't found much past the EGR block off. Any ideas for things to try next to get this issue under control?

Thanks in advance!
Dana

 

[SkiFreak]

Firstly, nice looking setup.

The 4M50 apparently has a reputation for overheating, but personally I have never experienced this myself (I have an Australian FG84).
Apart from having my EGR blanked off, I also have an engine heated calorifier in my truck. This adds about 6 litres of coolant to my truck's cooling system, which I am guessing helps a lot with maintaining a constant engine temperature.
It has been mentioned by some that the OEM temperature gauge goes from its mid position to red with only a few degrees of temperature change. I have seen a few trucks that have had an aftermarket temperature gauge fitted, so they could have a more accurate display of the engine temperature.
What I am eluding to here is that the red zone on the OEM gauge may still be within an acceptable engine temperature range, but I cannot personally confirm this.
Another option, again that I have not tried, is waterless coolant. I hear that this is used by some to overcome this issue.

On a different topic...
I see that you have removed the original front mudguards. I fully expect that if you go through any mud that you will get that dispersed all over your doors and mirrors.
There are some commercially available custom flares for this model (from ATW or AAV in Australia) which you may wish to consider.
Alternately, you can fit some rubber to the OEM guards to give them a bit of additional width.
I should add... with larger super singles, the OEM guards need to be trimmed to give clearance for the tyres, but that's a pretty simple and straight forward task.

 

[HD.Adventuring]

Thanks so much for this detailed response, @SkiFreak ! I have read so many of your posts on this site in researching this issue(and many things before this one.)


These are all great things to think about- maybe it's not actually "overheating", just getting warmer, like I would expect on a big climb. An additional temp gauge could be a great option. Knowing the exact temperature vs "red" will help manage the issue at the very least. A coolant flush is something I want to do anyways, so I'll look into the waterless coolant.

Yes, I removed the mud guards to fit the 37's. I kept them, so I'll add that to my list to trim them and then add some rubber to catch the mud. We certainly plan on getting this thing dirty, so I appreciate you pointing this out! I'll update this post once I've made any progress.

 

[weekenderdefender]

Second swapping out the gauge for aftermarket. I have VDO gauges in my Land Rover which are way more accurate than the originals.

Another thing to look for is air in the coolant lines. That’ll slow down flow of coolant for sure

 

[HD.Adventuring]

Thanks @weekenderdefender. I will pull the stock sender unit that goes to the dash and replace with an aftermarket sensor and gauge. Looking at both the engine and service manuals, I am not seeing a safe temperature range. Anybody know the "normal" temps that this generation of Fuso's tend to run at? I assume around 200F is OK, but these trucks defy assumptions from time to time.

 

[HD.Adventuring]

@billiebob that has crossed my mind too. Think I might order some waterless coolant, and do a flush ahead of that with the special flush liquid. Yesh, totally understand that passes are going to get it hot on hot days. I've now installed a thermometer, but still have not found any spec on what is the "safe" operating temperature.

 

[Bris31]

Another option, again that I have not tried, is waterless coolant. I hear that this is used by some to overcome this issue.
...

One of the waterless coolant manufacturer mentioned about possible issue as below to be aware of - wondering if it would be of much concern.

With waterless coolant, the engine will continue to run fine with restricted airflow, although it is possible that the plastic parts in the cooling system, such as the pump impeller or fittings holding the radiator hoses together, can melt.

 

[HD.Adventuring]

@SkiFreak this is a great point to consider. So far, I have yet to see the engine get above 200F on my newly installed aftermarket gauge. Haven't tested it on any passes yet though, so the jury is still out. Might just do a coolant flush and replace with standard coolant instead of waterless. Have also been put in contact with a shop that will custom build a 4 core radiator that could be a game changer in terms of cooling capacity for the system.

 

[SkiFreak]

Have also been put in contact with a shop that will custom build a 4 core radiator...

That would be the option I would go with, as it is the most logical and the most likely to have a long term, beneficial effect.

 

[HD.Adventuring]

@SkiFreak yep, the shop is in Oregon, and I'm in Colorado, might need to plan a roadtrip around it!

 

[SkiFreak]

Can you not get it built, then freighted to you?
Surely there is some competent company in Colorado that could install it for you, if this is a task you would prefer not to do yourself.

 

[HD.Adventuring]

@SkiFreak yes, I am sure that is a possibility as well. And I'd likely be able to do it myself, I do know there will be some modifications required of the fan shroud and potentially the mounting points for the radiator. Exploring my options at the moment.

 

[HD.Adventuring]

After installing the new fan clutch, doing a coolant flush, and adding the aftermarket thermometer, I hit about 205-208 degrees F on a pass on a 60 degree day with a bit of rain. Haven't had a chance to run it on a hot day. Does anyone have examples of water temperatures that these engines are safe to run at?

 

[weekenderdefender]

Anything past 210° is too much heat for me. That’s when I downshift and just let the traffic build up behind me 😂 or pull over if it doesn’t cool down

 

[kerry]

I've used Evans waterless coolant, but not in a FUSO. My understanding is that it doesn't change the operating temperature of the engine but increases the boiling point way above that of a standard coolant/water mix so the engine can be be cooled at higher temperatures. It also doesn't required a pressurized system since the boiling point is so high. I wouldn't think it is a solution to your problem if you want to keep engine temperatures low. In your situation I'd be tempted to install an EGT gauge as I suspect that while climbing mountain passes your EGT's are increasing substantially and causing the increased running temperature of the engine. Driving the vehicle to reduce EGT's might keep your overall temps in a range more acceptable to you. I know my old Wanderlodge bus with a CAT 3208 would see engine temps increase shortly after EGT's increased on steep climbs over mountain passes. Personally, I would at least run the heater when climbing passes as just that small additional cooling can be quite helpful sometimes.