5.4 troubleshooting
 

Im new to the 5.4 Triton, having had 7.3s for over 10 years. But due to current circumstances, I need to run this 5.4 in a 2000 F250 superduty, ccsb, auto, 4x4, about 234k miles... need to get 6 months to a year out of it, until I finish another truck project, then this one will get a 7.3/6spd swap. I know little about this truck, only put a couple hundred miles on it. Took it on a trade deal about a year ago, it's sat unused since then, til now.

Budget is tight, Im putting as little money into this as possible, but need it to get me to work this winter, so it needs to be reliable enough.

The issue is this: Its loosing coolant. Doesnt seem to overheat, but after driving home from work, it seems to have puked out the coolant reservoir cap, and after cooling down, is low. The heater doesnt warm up great, but does warm up, if you are running highway speeds, but goes cool if let sit and idle. Ive replaced the thermostat, seems to be oil in the coolant. Hate to think it has a blown head gasket, it runs too good, no white smoke out the exhaust, no water in the oil. When at idle, gentle rev of the motor (up to 1500-2000 rpm) produces 'gurgling' sound coming from heater core area.

As I hope its not the head gasket(s), and I've heard of both the oil cooler failing, putting oil in the coolant, and also heard of water pump fins/vanes wearing off and not pumping properly, could give the lack of water flow needed, and gurgle when rev'd... open to ideas and thoughts.

I plan to pull oil cooler lines, to see if oil comes out the coolant ports, which would rule that out.

Does the water pump use an o-ring that is reusable? I could pull it to check fins.

Try the oil cooler bypass first. You can join the 2 coolant lines and leave the nipples on the cooler open. You can pull the coil wires off to be sure it doesn't start and crank it over. If it barfs oil you shouldn't drive it anyway. You may get lucky and all it needs is an O-ring on the oil cooler. Otherwise, the oil cooler is available new as an assembly.

The gurgling would tend to rule out the water pump since it is not open to oil pressure or exhaust. Not to exempt it from needing replacement due to age & mileage but doubtful it is the focus of the issue at hand since you say there is no coolant in the oil. And yes, it uses an O-ring seal but I can't imagine why anyone would want to reuse it. Kinda defeats the purpose of having a cheap replaceable seal. And if you do open it, flush out the old coolant for all the right reasons too. I get it about saving money, but doing something slipshod is not cost effective even in the short term per your plan. If you fix it right you will have the peace of mind for a reliable ride to work and probably even an engine worth selling after you pull it for the swap.

So it sounds like you are on the right track, oil pressure is pushing into the coolant and the only places I know of where that happens are at the oil cooler and the head to block gasket. I'm sure someone will correct me if I am in error on that.

Im suggesting water pump as an issue due to poor circulation, not getting good flow at an idle causing poor heating at an idle as the symtom, and poor flow at highway speeds causing it to puke out some how. Temp gauge is never over half of range on the gauge, never feels hot at the hoses when I stop at work or home. (27 mile trip each way, gets worked gard coming up the hill to the house on the home end.) Im in thebarn now, looking for a suitable tube to use as a bypass for the oil cooler.

Temp Gauge is a fancy idiot light, only shows 3 positions anyway, cool, normal, overheat.
Again, not to rule out the water pump, but that sounds more like a coolant system over pressured due to oil pressure being pushed in.
There is no reason not to suspect multiple faults on a vehicle that has been sitting.
"Hoses never feel hot" sounds like a stuck open or missing thermostat.

Pulled cooler hoses, ran it a few minutes, no oil coming out of cooler ports.

Starting to seriously suspect head gasket(s).

Thermostat is new, just replaced it because there was no heat in the cab. Thats what got me looking into the cooling system issues.

Looking at the exhaust more objectively, there may be more vapor coming out than there should be.

Bummed out... wish I could just put the 7.3L/6spd in it now. Miss the diesel rattle and kicking a clutch.

Having driven the truck to work the past 3 days, topping off the coolant with water, its always low after driving 27 miles to work. Never gets overheated hot, barely warm, judging by the heater output.

Also noticed this... open coolant cap when cold, top it off, close cap, start truck and run for a few minutes and shut down, open cap, coolant reservoir will be far more pressurized than expected. Do the same thing, only dont put the cap on, and coolant gets pushed out quite quickly. Could exhaust be pressurizing the coolant system somehow?

No water in oil, fresh oil change recently, looks clean, and no loss/gain of oil level.

Cracked head seems likely to me, as a blown head gasket that could let compression push pressure into the coolant would also allow coolant into the cylinder when not running and contaminate the oil, and/or coolant would be burned when running as well as ruff running/miss from the affected cylinder. It runs great, doesn't seem to miss, and the vapor from the exhaust doesnt seem excessive, or much more than most other vehicles running in cold weather.

Frustrated to the point of dumping water to it, run it til it blows up... 'growl'

You may have a cracked intake or a bad intake gasket causing your coolant loss. Many folks have had the problem under the passenger side crossover, but 3 bolts are on the underside and you can't just remove the crossover by itself. There are many forums here if you search for "intake gasket" or "cracked intake manifold". Below are examples with a good How To video.

https://www.ford-trucks.com/forums/1...t-removal.html

https://www.ford-trucks.com/forums/1...take-leak.html

I would suspect intake if that's where it was leaking from, but its getting blown out the reservoir cap. And it smells like exhaust fumes coming out of the reservoir also. Its the pressurization before getting hot that has me confused.

Guess its time to park it... weather is getting colder, so straight water in the cooling system is likely to make things worse if things freeze and bust, and its starting to run a little rough on start up.

How common are cracked heads vs blown head gaskets? I dont have the time or money to replace heads or have them resurfaced. If I can put $200 into gaskets and misc parts and run it, fine. But if its more than that, I'll park it until I can swap in the 7.3 PSD/6spd.

Having never torn down a 5.4, where would I find decent instructions or guide? I'm mechanically inclined, and dont care to tear into it blind, but prefer to do my research first and have some idea what I'm up against, and what order of disassembly steps is best.

I pulled the thermostat out, and it seems to not blow out as much coolant, but (obviously) never gets very warm, which makes defosting the windshield in freezing weather a challenge... but no overheating issues.

Just gonna run it for now, when weather permits.

That is a sure sign the head gasket is blown. Compression is getting into the cooling system

Blown head gasket, My 5.4 Excursion did the same, passenger side cylinder 3 was letting exhaust gasses into the cooling system. I replaced both head gaskets along with all new timing components, resurfaced the heads and sid a valve job and truck ran like new.

I'm gonna agree that you either have a blown head gasket or a cracked head. I had a VERY similar issue with a 4.6L in my '97. The "gurgling" sound is a dead give away. My "cheap and short term" solution was to use Blue Devil head gasket repair. It worked like a charm, and held for more than two years until I sold the truck. AFAIK, the truck is still running strong today. I know a lot of you thin stuff like this is "snake oil", and I usually do too, but my father-in-law, who was a heavy equipment mechanic for 40 years, swears by this stuff. He's the only reason I gave it a shot, and I'm happy I did. For $60 bucks (and guaranteed to work or your money back) why not try it? The trick is to use it EXACTLY as directed.

Been running without the thermostat for a while now, its not loosing coolant, or maybe just not as much. Still hear the gurgle... doesnt seem to pressurize as fast eaither.

As to the 'gurgle' sound, can anybody explain how or why it happens, can hear it in the cab...