2006 Limited 4.6L Overheating

[White97Jimmy]

I've had on and off overheating issues with my truck since I bought it. I'm getting ready to move back to Detroit from Miami and have a ~1500 mile drive coming up in 10 days, unless I can't fix this thing and I am screwed out of my new job. I'm almost ready to just trade this in.

The problem:
Any load on the engine causes the engine temp to rise above normal. Engine fan kicks on (roaring sound) when accelerating from a dead stop or low speeds. Stopping usually lets the engine cool back down to normal temp. I've had to baby this thing back and forth to work since it's my daily driver, praying I don't get stuck in the Miami traffic.

I changed the thermostat and flushed in October and that solved the problem, until last week. That's when the roaring fan sound came back and then all of a sudden my engine started overheating.

I don't see any leaks in the radiator, coolant is full, still looks clean from my last flush and fill. A certified mechanic from my job swears it's the fan clutch. He stopped the fan with his hands when I started the engine up. I ordered a new electronic fan clutch that will be installed tomorrow. Only other thing I can think of is a clogged radiator or bad water pump. I pulled off the radiator cap and ran the truck up to temp. Does this look normal in my video, or should I be able to see the coolant flowing down through the radiator?

http://www.youtube.com/watch?v=uadYBU6ZdCU

Please help!

 

[White97Jimmy]

Replaced the fan clutch today. Definitely a lot more airflow and the fan doesn't spin when cold, but it didn't help at all. Radiator isn't leaking, gave it a really good look today. Only thing left I can think of is a clogged radiator or water pump. No one has any ideas?

 

[Bill MacLeod]

Couple of questions for you?

How are you verifing engine temps?
What brand & rating is the new stat?
System bled of all air bubbles?
Change any hoses yet?
Fill with correct coolant mix & coolant type?
Try a 16 psi cap?
How many miles on the rad?

 

[White97Jimmy]

Couple of questions for you?

How are you verifing engine temps?
What brand & rating is the new stat?
System bled of all air bubbles?
Change any hoses yet?
Fill with correct coolant mix & coolant type?
Try a 16 psi cap?
How many miles on the rad?

-Only seeing temps by cluster gauge. I have no other means of checking it as of now.
-Stat is a Failsafe, 195 temp.
-I've bled the system.
-Guessing its original hoses, inspected and look fine.
-Filled with Peak coolant and Water Wetter since I'm in FL.
-Couldn't find a 16psi cap down here. But just put a brand new Stant 20psi on yesterday.
-Guessing its the original rad. 78400 miles.

 

[Bill MacLeod]

I think the 4 litre motor uses a 16 # cap, so they are readily available.

Lots of heat from the heater? Both heater hoses get hot?

Can you get the system pressure tested?

 

[White97Jimmy]

Heat works just fine. Turning the heat on full blast does not help when the temp gauge rises. Don't know of any places around here to do pressure testing. I think I'm gonna try flushing the radiator out one last time. If that doesn't fix it then I'll have to trade it in.

 

[Bill MacLeod]

I have no experience with the Failsafe stat, but I wonder if its working properly.
Has the check engine light ever come on?
How dirty was the original coolant when you did the flush?
Do you have the original Ford stat? If so, can you test it in a pot of water?
Was this truck not well maintaned before you bought it? From you posts, sounds like it needs some TLC.

FYI, I did a flush, hose and belt change on my 06 last summer at about 50k miles. Original coolant was clean, stat worked ok so I didn't change it, refilled with Ford L/L Gold coolant.
I monitor temps with a ScangaugeII. This is a great "tool" to have.

 

[White97Jimmy]

I don't have the original stat. Not really sure how badly this was before I bought it, but the only major problem I've continuously experienced is the overheating. As far as TLC, I've maintained it pretty well, fluid/filter changes and pretty much keeping everything up to date. Only other issues that I've had seem to be the very common problems that are on this board.

 

[Ornery]

Are fuel injected engines capable of running lean? I don't know the answer to that question, but I do know running lean WILL overheat an engine.

 

[White97Jimmy]

Just finished draining, rinsing and putting 2 jugs of Prestone Super Flush in. I think it's a clogged radiator. With just the water and Super Flush, the fan doesn't roar while driving and I was driving in traffic with the AC on just for giggles. The jug says drive it for a few hours of road time over several days. My next day off is Tues, so I'll drain, flush and 50/50 mix then and see how it is the rest of the week.

Hopefully this will get me back up to Michigan, and then I can order a new radiator and replace in my garage where I have the proper tools. I'll keep everyone updated.

I also have a pic of when I took the radiator cap off of some of the gunk that was floating. I only put water in the radiator, and it was coming out with brown floaties and green coolant.

Also, the bottom hose was only lukewarm when I drained the initial coolant. I drove about 10 miles in Miami traffic on the way home and was able to touch the coolant from the bottom hose. Then it got scalding hot as it drained.

 

[White97Jimmy]

So bad news/good news. Fan is still roaring, temp gauge does go up, but it does seem a bit better. I really wish the traffic in Miami would be more chill so I could cruise at a highway speed and not have to worry about stop and go traffic. I'm hoping that the Super Flush is slowly breaking things apart.

I'm also thinking there may be some air trapped inside because I went to fill up gas, and as soon as I started the truck, it sounded like a gurgling/water flowing sound from the passenger side. That would be an air bubble in the system through the heater core, correct?

Attached is a photo of what underneath the cap looked like after running Super Flush for about 10 min. I'll have to see what lies beneath tomorrow morning when the engine has cooled off.

 

[White97Jimmy]

Drove to work this morning and it seemed a bit better, until I pulled into the parking lot. Temp gauge started to rise just above its normal spot. I was already at work so I didn't try driving it any further.

 

[Ornery]

Apparently, the only faults that can affect overheating are:

• Thermostat
• Coolant pump
• Internal engine coolant leak
• Radiator
• Radiator airflow obstruction
• Fan/fan clutch
• Radiator cap
• Airlock in the system
• Coolant condition /concentration​

I guess anything beyond those would throw a code. Two or three interesting videos here. A bad water pump causing overheating is rare, but not impossible.

 

[White97Jimmy]

I'm really at a loss at what the deal is. I'm going to try replacing the thermostat when I drain the Super Flush. I shouldn't have to be replacing the stat 4 times in 3 years though!

 

[Ornery]

Take out the thermostat and leave it out. Drive it a while, and if it doesn't overheat, that pretty much cinches it, no? Imagine bailing on a decent truck for the want of a $5.00 thermostat!

 

[White97Jimmy]

Alright, this is going to seem extremely stupid, but just for giggles, I burped the system tonight. After a bunch of water shot up after the thermostat opened, I put just over a gallon of water back in. Let it burp again, another half gallon in. I'm guessing that after the water shot out, I ended up really only getting 3/4 of a gallon or so back in, but that would be a big air bubble.

Drove it pretty hard, and other than the first minute of engine fan roar, I never heard it about the next 7-8 miles of Miami traffic driving. Temp gauge never moved. All this time it was just air? I've never had this much of an issue burping a system!

Anyway, going to continue to monitor over the next 2.5 days until I flush out the Super Flush. Looking like a step in the right direction!

 

[White97Jimmy]

Well cross off the above post. Turns out it wasn't that. Drove it to dinner and then to a friend's house, fan roar is back and temp gauge started jumping. I took a video which I hope someone will look at since it is a boring 2:30min of watching a speedo and temp gauge! You can see the temp jump up then back down, never getting above the 3/4 mark though.

http://www.youtube.com/watch?v=NS1Z7t31a1w

Here's something interesting: As soon as I parked my truck after this video, I grabbed on the lower radiator hose and it was just warm. The top was scalding hot. I know that the lower hose should be cooler since it is flowing the coolant after it passes through the radiator, but there's no way it would only be just warm. Could this be the water pump not pumping water around the system after the thermostat pops open? I am so frustrated and starting to worry since I have to drive to MI.

 

[Bill MacLeod]

Never seen a factory gauge fluctuate like that, they usually are not very responsive.
When you say that it has overheated in the past, did it actually boil over or did the gage peg only?

The deposits it the rad look like normal scale to me, I would just flush it numerous times, put a new ford stat in, good antifreeze mix, 16# cap and put in a new ford sending unit.
Make sure you have fluid in the overflow and have the front of the truck higher that the rear. That will help to get air out of the system.

Good luck.

 

[backroads]

Go to a radiator shop . They can tell you if it's the rad. on mine they used a heat tester gun to test the temp going in and out of the rad and tell if it's working. Your radiator probably had a leak and someone dumped a bunch of stop leak in there and now it's finally got atherosclerosis.

 

[BadThad]

Could it be the sending unit?