FORD 460 Overheating Mystery

[goprolocal]

1997 Fleetwood Southwind 35P ~Ford 460 engine.

I noticed the rig running a bit warm when we first got it 5 years ago. It had 23K miles on it then. It seemed each trip it would run a little more on the hot side of the dash gauge during long interstate trips. During stop and go around town, everything seems just fine, even when it's 110 outside.

Then we started flat-towing a Jeep Wrangler TJ. I expected the temps to increase but I noticed that on inclines, the dash gauge would nearly peg on hot. I could tell the rig was hot.. This would only happen on highway trips...worse on inclines.

One time after traveling for 2.5 hours at 60-65mph, we got off the highway and when we pulled into the gas station, the engine seemed to be vapor-locking..like it was starving for fuel. After 2 hours of letting it cool off, I was able to feather the throttle enough to keep it running to get it home. It doesn't do this vapor-locking thing unless we run long distances at a time, and not every time. It has only done it once before after a 40 minute incline. I actually unscrewed the gas cap thinking that maybe rapid fuel consumption from the tank cause some vacuum or fuel flow resistance..or ?

I then had the radiator, water pump, and thermostat replaced. No difference. I replace the fuel pump, changed the fuel filter, had the carburetor adjusted..no difference.

Thinking that the dash gauge could be off, I replaced the temperature sending unit and gauge with a number dial. The rig runs down the highway at 245 degrees if I'm not towing. If I'm towing, 245 to 258 degrees uphill.

I can hear the clutch fan kick in at 230 to 240 degrees or so...maybe sooner ..and it does cool it down a few degrees so I know it's working.

Are these temps bad? It seems high to me but maybe this is perfectly normal? I don't think it is. The rig runs perfectly..smooth as can be.

The problem seems like it has gotten progressively worse. Our last trip up to the mountains towing, it got to 258 degrees ...the highest I've seen it yet.

There are only 2 things that I can think of that could cause this.

1. Blown head gasket. This makes sense because the problem seems to happen under load. Perhaps there is a leak that's pushing hot exhaust gasses into the coolant? When things are under load, they heat up, causing expansion, and making the leak worse?

If this were true, I would expect to see some foam in the engine oil...but I don't.

2. Transmission issue. I believe the tranny is cooled by the same engine coolant. It shifts perfect, does not slip at all. I have no idea how to test to see if this is the cause of the overheating issue...any suggestions here would be appreciated.

Solutions.
1. Sell it.
2. Take it to a head shop and have the head gaskets replaced.
3. Put STEEL SEAL Head Gasket Sealer in it and cross my fingers. (Has anyone tried this?)
4. Pretend that these temperatures aren't anything to worry about until my rig blows up.
5. ??? Thoughts?

Thanks in advance for any insights.

[down_home]

They make coolant filters and adapters for all sorts of engines, especially the diesels. i have intended to have one added to our motor home. You know how that goes. Just two months ago had Freightlinenr change the coolant and should have done it then. Doesn't matter if it is a gas engine or diesel on a motorhome or any other vehicle it is a great idea. One time I looked up the cost, when Cat was still servicing their over the road engines in motor homes. Seems like it was around 300.00. Biggest decision is where to mount the base or adapter and substituting hoses to reach it....and of course add in the cost of another coolant change.

[Rocket9k]

Glad to hear you resolved this issue! Mine was multi-faceted as well. I had a factory radiator with the lower 6 rows completely plugged with sediment, and at least 8 more partially plugged. It ran hot all the time, and extended runs out of overdrive saw near overheating temperatures. A replacement radiator saw much improvement, but still not quite right. Turns out my fan clutch was weak as well.

I agree with your assessment about the radiator size. People have said it has plenty of capacity to do the job but it seems small to me, especially for a 18,000 pound rig. Subsequent years have much larger radiators as well.

Your rig looks to be in beautiful shape, good luck to you!

[rhagfo]

What percentage of antifreeze do you run? Most antifreeze on the market will give maximum boil over protection at 60% antifreeze 40% water.

[tiffy2000]

I once read a post where someone was overheating and had 2-3 aftermarket thermostats put in....put in a Motorcraft thermostat and fixed the issue. Have also read where some will drill a small hole in the flat plate in thermostat to allow any air to bubble through. Hope it gets sorted out

[time2roll]

Excellent to hear you are back on the road without worry. I would be tempted to flush again after a year.

[John_Joey]

So what weight oil were you running? Dino, blend, or full syn?

[goprolocal]

***RESOLVED***
Or as close as I'm going to get I think.

I just got back from our California vacation (Doheny Beach, excellent!) and the rig could not have run better! Ultimately, I believe the issue was multi-faceted. First let me tell you about how she ran on the trip.

We took I-10 from Phoenix and went through Riverside. We left around 9am to avoid the hottest part of the day but by the time we hit the big hill, it was 100 degrees outside. We flat towed our 2004 Jeep Wrangler Sport with a full load of 50 gallons of water on board plus gear and the 2 kids and their stuff.

This rig has always run perfect...just hot. It's never boiled completely over but it has run several hours at 245 degrees at 65-70mph and has been as hot at 257 degrees up grades.

This time was different.

On the straights she ran a nice cool 215-225 degrees at 65mph with the overdrive ON to keep the rmps lower. If I bumped it up to 70mph, 225-230 degrees and that's about as fast as I want to go towing.

On the serious grade, I maintained 45-50mph standing on the throttle and it heated up to 240 degrees after a couple minutes, and cooled right down once we leveled off to 225-230 again. Downhill I could see 215 degrees but no lower.

Most of the trip there and back, I was at 67mph between 220-230 degrees. If I slowed down a bit, it cooled a bit, if I sped up, it got hotter....about 1 degree per mph in either direction.

I've heard 460s run hot...I think what I have is a serious case of normal now! 🙂

Here is what I believe the fix was. The main thing is the overdrive. While towing, I was always taught to turn the overdrive off to avoid damaging the tranny. While that may be true for a pickup towing a toy hauler, it's not exactly true for my RV. Someone here in the forum pointed out that I'm not going to hurt the transmission running it with the overdrive on when towing my Jeep. So this trip I left it on and that was possibly the biggest factor in this whole issue.

The other factor I believe was **** in the block. We bought the rig at auction 5 years ago and it only had 23K miles on it then...almost nothing for a 1996-7 Southwind. That means it sat for a long time, and I'm pretty sure it sat somewhere really cold; as all of the plumbing was cracked from freezing (all replaced with red and blue pex now 🙂 ) I believe this long storage may have gummed up or blocked some of the cooling pathways in the block. The shop flushed the block 2x and both times they said a "bunch of **** came out".

I also swapped a quart of oil with some Lucas treatment that is supposed to reduce friction and lower temps. I don't know how much of a factor this was but it definitely quieted my motor down...sometimes at high rpms, right before it shifts, it can sound a little 'clattery' if that's a word...but not anymore.

I also poured some radiator treatment in the overflow bottle that claims to lower temps up to 10 degrees. It said it would take 4-5 heat/cool cycles before it makes it all the way into the cooling system so this probably was not a factor.

The interesting thing is that if I turn the overdrive off, even if I'm not towing anything, at 65mph it will be 245-250 degrees in 15 minutes on flat ground. It seems the high rpms are creating more heat than the radiator can handle...which is the last factor...the radiator.

We replaced the radiator when we first bought it because of a crack in the seam. I had noticed it ran a bit on the warm side when we first got it and changing the radiator, water pump and thermostat changed nothing regarding the hot condition. I believe the radiator that the rig was built with is on the small side...I'd even say it's too small. A larger radiator or possibly and electric fan of some sort might alleviate the hot condition altogether.

One other thing someone said to me was to consider getting a larger oil cooler...as it is a factor in the engine temps too. I may look into that...do you think it would help?

Overall, I am so thankful to all of you that have given your suggestions and input. I brought each one to the shop and ran it by the mechanics...a few they hadn't thought of on their own!

What a great resource this forum is. Thank you for your expertise fellow RV'ers. I love my rig...logged 7 hours today and I'd turn around and go right back. 🙂

Ken
1996 Fleetwood Southwind
2004 Jeep Wrangler

[garry1p]

AS I posted I went through the same problem never did get a 100% fix but improved to usable 220.

Since non of my previous suggestions helped my last great guess is a restricted exhaust.

[goprolocal]

alvie h wrote:
Have you had your engine timing checked. To high or to low will make a engine run hot. Just something that will not cost you a arm and leg

I'll be sure they check this. I thought it could be running lean too.

[goprolocal]

rgatijnet1 wrote:
Do you have access to a ScanGauge, or similar type gauge to hook up to your OBDII connection to get an accurate temperature of the coolant?
Do you have one of those inexpensive laser temperature guns to check around your coolant flow path to see where the temperature is being generated. In other words what is the temp of the coolant in to the radiator and the temp out of the radiator.
I believe that your transmission fluid also runs through your engine radiator. Is there any chance that your transmission is running hot, for whatever reason, and this is affecting the engine coolant temp?

I did talk to my transmission shop. They said that if it was caused by the tranny, there would be tranny issues. This rig shifts smooth and perfect. I've used the laser temp but I'm not able to get an accurate reading I trust from parts of the block and radiator.

I'll ask the shop if they've hooked up the obdii. I remember them saying they had trouble finding it. Will let you know. Thanks for the input!

[goprolocal]

patperry2766 wrote:
You're not running straight antifreeze are you? Don't remember seeing this commented on, but I could have missed it.

Nope, 50/50

[rgatijnet1]

Do you have access to a ScanGauge, or similar type gauge to hook up to your OBDII connection to get an accurate temperature of the coolant?
Do you have one of those inexpensive laser temperature guns to check around your coolant flow path to see where the temperature is being generated. In other words what is the temp of the coolant in to the radiator and the temp out of the radiator.
I believe that your transmission fluid also runs through your engine radiator. Is there any chance that your transmission is running hot, for whatever reason, and this is affecting the engine coolant temp?

[patperry2766]

You're not running straight antifreeze are you? Don't remember seeing this commented on, but I could have missed it.

[alvie_h]

Have you had your engine timing checked. To high or to low will make a engine run hot. Just something that will not cost you a arm and leg