Ford 460 motorhome running hot

[TheWanderer]

Hello again everyone!
Just wanted to check in after all the recent repairs with a new and exciting issue! Haha well kind of new.

So the 460 engine in my 1988 ford E350 motorhome is running pretty well, idling fine, starts fine, runs down the road with no spitting or sputtering...except that it is running temps up to about 220 when run for very long at all, and still seems sluggish on accelleration or under load particularly when hot.
I ran it about 200 miles the other day and it got hot enough to melt the split loom off my plug wires. I heat wrapped a few things like the egr pipe and exhaust near the starter to reduce wear on components and heat in the cabin but need to figure it out within a couple weeks if possible before any longer runs again.
I am about 6 miles from the nearest town and they do have an advanced auto there. Can probably safely run it about 15-20 miles round trip at a time before needing to let it cool down to avoid extra wear on stuff. Further if absolutely necessary. Hoping for no big money repairs as I already went pretty broke with previous repairs.
Thinking perhaps a fuel pump or injector issue?
I will list the replaced parts and work done to get it to this point.
Crankshaft and bearings
Oil pump
Oil pan
Map sensor
Battery
All spark plugs
Purge valve solonoid
PCV valve
Any problem vacuum hoses
Fuel pressure regulator
Catalytic converter
O2 sensor
Full fluids change
Water pump visually inspected
Fuel filter cleaned out with no improvement noticed.
Distributor contacts checked and cleaned.
Perhaps another couple odds and ends im not thinking of.

[TheWanderer]

Very good info again, thank you!
And yeah I inspected the water pump impeller but didnt want to break the gasket for the housing and pay for more parts I didnt think I would need. (I was already nearly $2000 into parts/fluids and was broke. Lol)
Also, I didnt remove the motor. I did the rebuild work from under the RV by tearing things down and raising the engine about 8+ inches. If I had to do it again I would pull the motor. Haha it was hell.
The thermostat I just hadnt thought of because I didnt know what was causing overheat at the time. Bearings were worn, oil pump shot, etc. However, that is pretty easy to swap on the road. Just gotta take air exhange box off, and disconnect rad hose and there is 2 bolts for the thermostat right up top of the engine.
Plus a thermostat only runs $10-15 so its worth me doing soon. Probably shoulda been done already.
Also, as an update, I drove the rig a couple 50 mile stretches, mainly early morning hours driving when it was cooler out, and it only hit 200 when climbing hills. Never went over 202 or so even on a bigger hill. Im feeling like it might be more: A: older engine tech. B: loaded to max weight. C hot weather and elevation change.
And Im cringing a bit because apparently I was about 1.5 quarts low on transmission fluid for about 100 miles. I just checked it 2 weeks ago, but the fluid musta finished cycling through as I drove more. Topped her off and got another small drop in temp but kind of feels like there is a mild shudder under heavier loads in low gear that developed and made me check fluid levels and discover the low level.
Really hoping I am not having torque converter issues from the low fluid driving. Topping off the tranny fluid reduced the shudder some, but its still present under heavy load. Will be investigatimg more as time goes on.
*Rant Over* ??

[4x4van]

A couple of things here. I don't think that 210 is too concerning for a 1988 460 in an RV, climbing hills. It's an old technology motor, a heavy rig, and class C doghouses tend to hold the heat in. My last RV was a 26' Jamboree class C, 1988 with the 460 as well. I didn't have a "numerical" gauge, but I would regularly run at least 3/4+ on the gauge while running in the heat under load. Also, I wouldn't go too crazy with heat wrapping things; it can do more harm than good by holding the heat in rather than allowing it to dissipate.

BTW, you did alot of work on rebuilding this engine, but didn't replace the water pump, thermostat, or fan clutch? For the cost, and the ease with the engine out, the water pump would have been a cheap/easy bit of insurance at that time. Now, it's alot more work to change that unit out. Yup, been there, done that; the water pump on that beast covers pretty much the entire front of the motor!

Also, although it's a different rig and drivetrain, on my '04 class A Workhorse 8.1, the fan clutch doesn't even kick in till about 208-210, and then drops back out when the temps go down to 204. So again, I'm not sure that 210 under a load is time to panic.

[72cougarxr7]

I would recommend a Stant "superstat" if you can find one. It is their premium thermostat line and is made of stainless steel, has a larger opening to flow better, and has a larger heat motor for more accurate opening.
If you are running 200 to 205, that is not bad. The thermostat is likely a 195, so 190-200 would be the normal temp range.
The existing thermostat could be old and getting slightly lazy, causing it to open a few degrees hotter than spec .

[wnjj]

TheWanderer wrote:
The clutch fan does spin by hand with minimal resistance, and I know it turns well rven at idle so I doubt the fan is the issue, but Im sure some wd40 and cleaning wouldnt hurt!

With a clutch fan, there's turning and then there's really turning. If the clutch isn't fully engaging when it needs to you won't get the maximum cooling. When it kicks in there's should be no doubt. It will sound like a small jet is taking off under the hood. If you don't hear that distinct change when it gets hot I'd look into it more. You should also hear it slowly fade away when it cools enough.

[maillemaker]

My 1990 E350 RV with 460 engine now has a rebuilt coolant system (195F theromstat), and I installed a digital temperature gauge plumed to the thermostat housing neck.

With ambient temps in the high 90s, with the air conditioner on, my temps hover around 188-192. When the transmission kicks down to go up hills, it may spike to 200-202 but immediately falls down into the previous range.

Steve

[maillemaker]

Assuming that you mean distilled water MIXED 50%/50% with the appropriate antifreeze/coolant? (see owners manual)

Yes, of course.

[TheWanderer]

Great tips and info!!
I am begining to think it is more an issue of being maxed on weight, 90 degree temps outside, and I feel like the computer may still be adjusting?
I took it for about 20 miles twice today, lots of up and down, and only went over 200 when working harder to climb hills. Never went over 205 today though.
I am definitely planning to just flat out replace the thermostat, it costs all of $10 plus coolant. Haha
I will have to see about the IR gun method, there doesnt appear to be any mineral deposits when I look in the cap or top outlet but there could be further down..
The clutch fan does spin by hand with minimal resistance, and I know it turns well rven at idle so I doubt the fan is the issue, but Im sure some wd40 and cleaning wouldnt hurt! I will update when I get a chance to do some work and get some test drives in. 🙂
Thanks again!

[Gjac]

Glad you got the timing straitened out. 200 F on a flat and 220 on a hill sounds normal to me for an older 460. I would do several things to reduce the heat. Remove your thermostat and put it into a pan of water and see if it opens a 1/4 inch or so. I have seen several new ones only open 1/8 inch. You can use a good chemical flush in your radiator and drain before you remove the thermostat then reinstall the housing and flush the radiator from the lower hose using a garden hose. Without the thermostat in the way you will flush the whole system and see a lot of mineral deposits come out the drain. Also you can check you radiator before and after the flush with a IR gun in a grid pattern every 2 -3 inchs from top to bottom. When radiators clog they seem to clog in the middle and much colder readings would indicate a clogged section. You should see a delta T of 40-50 degrees F from top to bottom on a functioning radiator. There is a viscous fluid inside the fan clutch and if it leaks out it will not engage the fan. Look for leakage on the clutch also clean the spring in the center of the clutch on a 1988 it is probably covered with dirt which insulates the bi metal spring which controls the fluid into the clutch as the air temp rises. The fan blade should spin by hand with some resistance. There are other things to try but try these things first and let us know how you make out.

[TheWanderer]

PaulJ2 wrote:
OEM thermostat is likely a 195 as are most vehicles now. So 200 would be about normal operating temperature. When climbing a hill you may see about 210 or so at which point the clutch fan should start to engage causing a loud roaring sound. If this does not happen i would suspect a bad fan clutch.

The large fan within the shroud of the radiator spins at all times but does spin faster with higher RPMs I believe.
I am thinking a 195 or 180 stat now, but still tossing options around. And yeah it only nears 210 when climbing hills or lots of stop and go. Idealy I would like to be 200 tops though. Maybe I am expecting too much of an '88 V8 big block hauling max weight?
Mainly it just gets the hood, grill, interior heat shielded 'hood', and anything near the manifolds and exhaust hot which concerns me about wear on components. I did heat wrap the exhaust pipes for the EGR tube, and the exhaust near the oil pan and starter. Also heat wrapped the purge valve solonoid because it was almost melting after a longer drive.
Does the engine computer take a long while to adjust things after a timing adjustment? Perhaps I havent driven it far enough? I wondered about that as well.
Thanks!

[PaulJ2]

OEM thermostat is likely a 195 as are most vehicles now. So 200 would be about normal operating temperature. When climbing a hill you may see about 210 or so at which point the clutch fan should start to engage causing a loud roaring sound. If this does not happen i would suspect a bad fan clutch.

[TheWanderer]

Hey everyone!
Wanted to get you an update, as today I brought the RV in to have the ignition timing adjusted to spec. Found a really great garage here in Troy NC called Steves Auto Repair. Steve worked with me and is a Ford Certified technition.
My timing was off by 20 DEGREES! 😧
Thankfully having it corrected seems to have fixed my lack of power issues!!
The RV is now able to accelerate up hills (albeit slowly, it is 11,000 lbs. Lol) and accelerates from a stop fine now! Overall the engine itself is performing well now, idles fine, good acceleration, quieter, etc.
However...
The overheating issue still remains. The temp on my gauge I installed reads about 200 regularly while driving, and while it doesn't near 220 anymore after the timing adjustment, it can still reach up to 210 under heavier load. Keeping my drives to short jaunts for the time being.
I am considering starting with replacing the themostat. It should be fairly easy and not overly expensive to at the very least rule it out. The coolant circulates and the pump impeller looked fine when I removed it during rebuild. I am wondering if the thermostat isnt quite opening enough. What temperture rating would be recommended for moderate climate? I dont need heat in the cab much I would rather a cooler engine. What is OEM for a '88 Ford 460?
The radiator does not look like it has buildup at least anywhere I can shine a light in.
I will be rechecking fluid levels too for oil, tranny fluid, and coolant. Coolant was just topped off recently though.
Getting so close to having her running right though! *fingers crossed*

[T18skyguy]

If the radiator is original, you might get good results with a new one. Possibly with more cores.

[RLS7201]

Chum lee wrote:

Lynnmor wrote:

Chum lee wrote:
"As a result of this, I am a believer in using only distilled water with a radiator."


Assuming that you mean distilled water MIXED 50%/50% with the appropriate antifreeze/coolant? (see owners manual)

Using deionized, RO (reverse osmosis) or, bottled drinking water is also fine as long as it is mixed with the appropriate coolant.

Stay with only distilled water, bottled water can have minerals and DI or RO can have contaminants if not handled perfectly.

Oh please. So it's good enough to drink, (actually preferred) but not good enough to put in your radiator. Yeah right. Where did you take your chemistry classes? That's what I thought.

What do you think happens to distilled water when it comes in contact with common metals found in any cooling system? (rhetorical question) You need not answer.

Chum lee

Mr. Chum lee,

I had the privilege of working in the ink business, where we did a lot of formulation of water based inks. Lynnmor has it correct. Distilled water is far better for your cooling system and batteries. If you do some PH research, you'll find that distilled water has less solids and reduced the PH of antifreeze far less than DI, RO or bottled water. We actually had RO and a boiler for distillation for some of our fussy inks. The distilled water always performed better for hard to formulate products. Why settle for less when we know what the best is.

Richard

[time2roll]

My owners manual says distilled only.