I'm hoping some folks here might be able to provide me with a little info or ideas. I've searched the site a bit, as I try not to ask questions that have been rehashed to death, but I don't think I've found what I'm looking for...

Here's the deal - '96 F350, 460FI. 88k miles. When I purchased it (2-3 weeks ago) driving home the temp gauge kept spiking up, especially on the level with the overdrive on (auto, E4OD). Turning the overdrive OFF, and pulsing the accelerator helped. Going UP hill the temp would appear to drop.

Newer radiator, I've checked all fluids, replaced thermostat and temp. sending unit. New exhaust manifolds (no leak for now!)

Temp still spikes up (all the way to H if I let it), but none of the other signs I'd expect from overheating (oil pressure dropping at all (stays steady), extra-hot heat (I've turned that all to try and cool it down more. Doesn't do much, if anything) hoses don't seem any more hot than they should be, no overflow of coolant. No check engine light either.

I took it to one of the top shops in town, they felt it might be running a little warm but wasn't overheating, despite what that gauge said.

I'm waiting for a non-contact (infrared) thermometer to appear so I can check for myself. I may also put in an after market temp gauge with actual temps vs 'NORMAL' stock gauge.

So, my questions...
1) Has anyone experienced this, and what was the solution / problem?
2) What temp should different part of the engine be at (manifold, hoses, etc...) with a 190 degree thermostat (for when I get that fancy thermometer)
3) What temp should an aftermarket temp gauge be reading? As the thermostat opens at 190 I'm assuming warmer than that, but honestly don't know.


Thank you all in advance for any advice / assistance.
Adam
P.S. I doubt it is related, but I also have the Ford "wobbling speedometer" problem at around 60-65. As I usually drive around town I'm not sure i'll fix it (already replaced speed sensor, so I'm assuming the problem is the PSOM from my reading here)

 

A bit more trouble-shooting today... borrowing a non-contact thermometer when the factory gauge is near the upper end the thermostat housing is about 207 F. Radiator and everything else is plenty cool.

Current theory is new radiator (put on by previous owner) may be undersized.. but looking up the year of the truck, I don't see to many radiator options. I'll be measuring the core width tonight once she cools off.

Hauls 4 yards of mulch very nicely

 

The stock gauges are not very accurate at all. Did you know the oil pressure gauge is controlled by a switch? As long as you've got 5PSI of oil it'll say you're good. If you really want to know what's going on with your engine, get some aftermarket gauges or another way to monitor the temps.

As for your issue, sounds like air pockets to me.

 

Depending on what your thermostat is, 207° is not that hot especially if you have a 190° thermostat (you probably do have). If it was me I'd change out the temp sender and change the thermostat.

How many core radiator do you have? If it is less than a 4 core, someone sold you the wrong radiator.

 

Thermostat and sender have been changed.

I didn't know that about the oil pressure gauge - good to know... monitoring that is my other old school way of knowing if she's getting to hot... yikes!

The previous owner put the radiator in, so my next step is figuring out what it is (2 core, 4 core, etc...). I plan on measuring it's dimensions to start.

Fluid is definitely flowing (ran with the cap off, you can tell when the new thermostat opens up), so unfortunately I don't think it's air.

I suspect the gauge, or an undersized rad.

Keep the comments coming though - I thank you greatly!

 

207* should put right in the middle of "normal"
sounds like your gauge or sending unit is bad
I'd change out the sending unit, maybe get an aftermarket gauge

I wouldn't be worried unless your temp gets above 225* (shut down immediately if it goes above 245)

(I've got a 160* T-Stat in my GTO, normal running temp on flat ground at 70mph (1700rpm) is about 175-180)

have you checked your fan? is it coming on when it should?
have you checked your fluid mix?

you could also consider adding a coolant helper (like Royal Purple Radiator Additive or Red Line Synthetic Oil - WaterWetter® Coolant Additives, or Kwick Kool Radiator Additive, Radiator Flush, Radiator, Performance Radiator, Autosave, or LUCAS SUPER COOLANT, 16 OZ., or many more)

 

Fan is good, as is coolant mix.

Sender is brand new (and didn't solve the problem).

Sounds like it's time to get an aftermarket gauge, and either try and use the same sender (doable?) or get a mechanical one and try and figure out what to tap in to the system (I'm new to the 460... any available ports in a '96 EFI engine?)


Thanks again!
Adam

 

Well, short term the jury is still out. I took out the factory sender, put in a "T" fitting, and put both senders in (bleeding the air out as I screwed the second one in). Took it for a spin, mostly to check for leaks (long day at work, voting (school budgets around here), and it's after 11pm. Heated up and ran normal for once, new temp gauge displayed sitting in just above 190 (195 degree thermostat, so that makes sense). I'm going to try and go for a spin on the interstate tomorrow (normally what will make it get hot in theory). I did notice one amusing thing though - turning the lights on and off (headlights) changes the temp, oil pressure, NEW temp, and voltage (that I expected). Not a whole lot, but it is a noticeable repeatable movement in the gauges.

At least I got the windshield washer working at least! (new pump).

 

Well, it's been a few months

Aftermarket (real) temp gauge with it's own sender seems to indicate it doesn't get dangerously hot, but sometimes it does climb to 220 or so. I don't get nervous until it tops 210 (running a 190 thermostat), and I gather until it gets over 240 I don't really need to shut her down. Most of the time (non interstate) it sits at 190 or so once it's warmed up.

I have to travel up to do some plowing this weekend - it will be interesting to see if it overheats or not (it got warm on the way down here, no plow on with temps around freezing).

I do think I've figured out, finally, that it is the stock radiator, which is a 2 core. I think my next step, if it keeps getting warmer than I'd like at times, will be to replace it with a 4 core rad.


Do you think a 4 core rad will solve this once and for all? The fellow had just put this radiator in when I purchased the truck (well, last year or so), and I hate to toss a new rad, but if it will solve the problem it's worth it.

Thanks, and happy Thanksgiving!

 

Yup, still running warm. BUT I think I'm getting somewhere:

Replaced fan - the clutch siezed, and I began wondering if perhaps that was the whole problem - wasn't going fast enough at higher speeds and actually making an air dam. Good theory, and perhaps part of the problem, but still gets a bit warm (read 210-220). Around town still sits at 190, as well as plowing.

Had transmission checked out, not in perfect shape but very servicable and no issues (found a reputable shop that treated me very well too... if nothing else that is worth something!)

Doing a bit more reading it appears the VSS sends signals to the PSOM, which in turn helps with engine AND TRANSMISSION management. So my current theory is perhaps the tranny isn't downshifting when it should because of the lousy readings from the PSOM (the over-temp seems to only occur at freeway speeds after all...).

I'll keep updating this thread... hopefully it will help someone else out! Or if someone else has had similar problems, hopefully they'll let me know!

 

I'm working on a similar issue with my '86 460 E350 van.

After replacing the temp sender, thermostat, radiator flush, instrument cluster voltage regulator, and fan clutch the temp gauge still reads about the "A" in "NORMAL".

But for a real thrill I can turn on my lights and heater blower and the temp gauge will then climb up to the "L".

All the while I'm reading 207 +/- at the t-stat housing with the infrared thermometer...

I'm beginning to think it's a bad ground. Next chance I get I'm going to look for a broken / missing engine block to firewall grounding strap...

Maybe take a look at yours and let us know if you find (or don't find) a ground from the engine block to the firewall.

 

Well, finally took it to a dealer (with a good rep). They suspect a blockage somewhere, as they agree not enough flow. With any luck it will be an internal collapsed hose (or even just the "new" radiator that was in it when I bought it). Keeping my fingers crossed it isn't internal to the block.

After seeming to snicker that I thought it was the PSOM unit needing replacement for my wacky speedometer they agreed that is indeed what needs replacing.

I'm hoping the truck isn't too old for them (1996...)

 

Well, the dealer flushed the radiator, the block, flow tested both, put it all back together... and it still got warmer than it should (they agreed it wasn't "normal"). So, they went back and followed one of my earlier suggestions from this board - replaced the thermostat with a Ford one (previous was 1 year old aftermarket made in USA)... and that did it.

SO, lesson learned, despite the fact that quality aftermarket parts SHOULD work, sometimes you have to get the actual honest to goodness OEM part and not the "supposed to be same as OEM" part.

They were a bit embarrassed to have tried all the pricey things first, but had no trouble charging me for it. BUT, I guess at least I know the rest of the system is healthy...

 

I did notice one amusing thing though - turning the lights on and off (headlights) changes the temp, oil pressure, NEW temp, and voltage (that I expected). Not a whole lot, but it is a noticeable repeatable movement in the gauges.


You sir have a loose ground connection, most likely the engine to chassis strap is missing (seen this a lot) or the connection points are corroded.