I tow heavy and sometimes up long desert grades. Our combined weight on the Excursion and Arctic Fox is about 18,000 lb. Basically, even at 140,000+ miles, I have pretty good experience with this tow rig.

However, I sometimes allow the cruise control (65 - 70 mph) to stay on too long on long grades and see EGTs exceeding 1400F. At 1400F, I kick it out of cruise control and manually control throttle to get EGT back down. If I'm a little late doing this, I sometimes get a very high pitched (like a drill bit on stainless) squeal.

I'm worried that the turbo bearings are going. I'm also curious why my EGTs are quite so high as I've put on MBRP 4" exhaust and a BANKS Techni-Cooler system.

Any advice?

 

Just a couple of thoughts. An air leak in the CAC system can make a squealing noise, also it's easy to pull the cold side CAC tube off the turbo and check for play and smooth turning of the turbo impeller.

 

I too have this noise but not having an EGT gauge I have no idea what my exhaust temps are at the time. I just returned from a 4800 mile trip in the western states and was in the Rockies throughout most of the trip. I noticed a very high pitch "whistle" at high temps when pulling a long grade. In my case it seemed to be connected to the speed of the cooling fan. At a certain fan speed it would scream like crazy and when the fan increased in speed it would stop. When the fan would slow it would also stop. This also occurred after topping the hill and while descending the other side until the fan either slowed or stopped. Is it the fan, turbo, or what??? On this trip I was pulling our fifth wheel and gross weight was a tad over 19,000# My 2007 F250 is bone stock except for a coolant filter and it has 48,000 miles on the clock. The Edge Insight shows no codes and I am puzzled as well.


Steve

 

Degas bottle purging can sound like a tea kettle

 

I have heard a few drive belts squeal when the cooling fan begins to get into the higher percentage of its duty cycle. That can be from a worn belt or tensioner.

 

The squeal I am hearing is not just leaking air, leaking degas bottle, or slipping belts. Mine really sounds awful--metal on metal sort of squeal. It goes away as soon as I reduce EGT by taking over throttle control from cruise.

 

I may take a second look at this after I follow Rusty Axelrod's advice and check the compressor bearing. It seems odd that I only get this when the EGTs are really high, but maybe that is the only time that fan clutch is fully engaged(?), increasing load on belt and tensioner.

 

A thought about your EGT's.

I see you have an SCT in your signature. What kind of tune are you running while towing, because that's a pretty good load you're pulling.

 

I have towed with "8K Tow" and with "Unlimited Tow". I have heard but do not know for a fact that the "Unlimited Tow" is the factory tune. Both tunes give the same high EGT issue if I let the cruise keep trying to maintain speed.

The truck seems to run a bit better and get better economy on the "8K Tow". My thinking (hope) is that the studded heads allow me a bit more leeway on this.

 

I think the part in red is your EGT problem.

The studs might save your headgaskets but they won't save your pistons.

 

What would you consider max EGT for maybe 10 seconds?

 

It's not a max EGT thing it's a sustained EGT thing. 1400 isn't bad in a 1/4 mile run down the track. I've seen a LOT higher temps doing that, it's how long you keep them at 11 or 1200+. See where I'm going? I've pulled at 1250 for a good bit (minutes) but I watch to see what EVERYTHING is doing temperature wise and judge from that.

I personally will NOT tow on cruise, but maybe that's just me and my slightly not stock truck.

 

My stock tuned truck will run as high as 1350 but rarely creep into 1400s. Sustained towing hills over 1200 is ok, so long as its not over 1300 y ou should be ok, but that depends, how is oil temp and coolant a d are they controlled. I have never had a hill up here in the mountains get me over 1400 and stay there with stock tune, so I think your tow tune is perhaps a tad aggressive.

I think the other poster talking about a squeling bearing in the belt tensioner may be your noise. I have had one on rare occasion, usually first tow of the season as the fan never runs on high all winter here, but soon as we are towing she comes up over 218 water temp amd the fan amps up, the squel starts and eventually goes away after a few miles. It's does sound metal on metal, but I can find an issue with either bearing or idler ect. Belt is new and tensioned properly. So, just chiming in this could be your noise issue. While you are checking turbo end play have a look at the idler. Do you have digital gauges to watch pyro, coolant and oil temps?

 

I have an EDGE CTS programmed to monitor ECT, EOT, TFT, Boost, and EGT. I put their EGT probe in drivers side exhaust manifold. The absolute highest EOT i've seen on this hot trip has been 231F. The highest ECT has been 227F. The transmission has been well behaved and I have not noticed any temp above 190F.

My fan clutch seems to be pretty effective. If I do a long grade climb and it kicks in, it will bring the ECT right down below 200F if I then 'level out' at the top of the grade.

Sometimes I wonder if my EGT probe is reading high...

 

This is an old thread, but for someone experiencing the same thing that reads this later on, I'm willing to bet money that you have a cracked bellow on your Up pipe.

Mine cracked recently and on a cold start up it will whistle quite a tune until the turbo spools up.

BD Diesel up-pipes will be going on to upgrade and replace my stock Ford up pipes.