4.0 overheat but only just

[Armor64]

Hi all, alot of great info on here but I need some help.

My sisters 2008 4.0 4wd family mover is overheating, and they have limited money so I'm trying my best (I usually work on pre 72 classics)

- Replaced the waterpump as there was some shaft play, but it still gets hot.
- We ran the exhaust gas check, no issue there so doesn't look like head crack or gaskets, even had the system under vacuum with the kit, no gas or anything.
- thermostat opens at 190ish, verified with hose Temps and temp guns
- if you sit still, it stays at temp,driving around at 50kph, it Gets hot, scan tool said to 235 (stopped immediately at home)
-no excess moisture out exhaust or smoke/sweet smell, no oil in coolant or cool in oil.

Would the rad be done, or the clutch fan? Each would be 200 canadian peso each, but I don't know what to do. I hear the fan roar I guess when the electric clutch kicks on and off, and no heater issues at all.

Thanks all
Morgan

 

[Explorer_PL]

I would look at the radiator and debris in the front, airflow restricted ? Air in the system ?

 

[Adolpho Cepeda]

leaking any fluid? in the engine bay or on the ground. Also are you sure the thermostat is opening? It may be working intermittently.

 

[tripplec]

Yeah, if you're replacing anything the Thermostat is the first and with a Ford Motocraft one! A water pump won't cause overheating. If its leaking, its leaking but it does not cause overheating. Odds are there isn't enough coolant or a big enough air pocket in the system. Checking the level at the rad cap is what needed, not the over flow jar.

 

[Armor64]

No, there was no leaking on the car before the overheat (she always checks and parks in her garage), the first warning was the temp gauge pinging after driving the kids around, after that it puked fluid in a parking lot. it was taken to a shop (friends) who swapped the stat with an OE one, which they verified worked, but still allowed it to overheat. Because they didnt have a lot of money for the shop, i trailered it home with my 78 gmc and dug into it.
-noticed some play in the shaft/pulley on the water pump.
- replaced the water pump with a decent rated aftermarket one.
-drove around after clearing air pockets in the system, heater blows hot, thermostat opens but temps keep rising. i stopped at home when the bluetooth tool and torque app said i hit 230.
-no puking, overflow tank remained at good level, after cooling rad was at good level (do this alot with older cars, never trust the overflow alone)
-bought the exhaust gas/ blue to yellow fluid test, no result after testing for 45 mins (various tests with it at temp while sitting still on the driveway.
- i even put the system under a slight vacuum with the tool (slightly collapsed the upper rad hose) and it stayed that way until i removed the tester tool(10 mins at idle and 5 @ 1500rpm), so i don't feel its getting exhaust gases.

the radiator seemed ok on the outside, but i didnt remove it when drained for waterpump, only checked that there were no bent fins, but idid take to a carwash and spray from the front as a hail mary, but with the AC condensor in the way, doubt it did much.

i lucked out and found a replacement radiator for 100 plus shipping in canada, so i will attempt the swap this weekend, as the only other part is the fan clutch, but its 250, and i do hear the fan roar as it goes on and off, wish it was an electric fan, easier for me to fix.


when i pull the rad i will check it over for debris in case i can save using the rad.

thanks

 

[Tech By Trade]

Careful with that rad. The fittings for the transmission cooler are notorious for not fitting tight and leaking transmission fluid after replacement. Also, can I recommend pulling the upper thermostat housing and filling the block with rad fluid then installing the housing and topping up the system. It guarantees no air bubbles. Also, rock auto is a life saver, even with shipping from the us they are 3/4 to half price local in Canada. Also, for OEM Ford I get parts from White Bear auto nation. They ship USPS and are 3/4 the price of Canadian stealerships after shipping.

 

[Armor64]

Good info on vendors, will definitely look into them going forward, and hope for the best. Thanks

 

[PotatoExplorer]

Is the fan "roaring" when it begins to overheat? If you only hear the fan intermittently instead of consistently when the temps climb above normal then I'd guess a fan clutch is on it's way out. I just went through something similar where the thermostat began to fail. Vehicle would drive normal, but once it started to get a tick above normal operating temperature, the fan clutch locked up full time to try and reduce the engine temps. My fan cooled the temps down enough to never register a spike above normal on the temp gauge so I was completely clueless until the thermostat failed completely.

 

[Armor64]

the fan roars at low speeds, and when AC is turned on, as well as when it hits temperature, really noticeable at low speeds in first gear, almost thought it was a drive line noise at first, may still be i suppose.

 

[PotatoExplorer]

If the fan clutch is locked up even after a minute or two from a cold start then there may possibly be something wrong with the fan clutch... but a locked up fan clutch wouldn't be related to your overheating issue. Maybe try purging the system of air bubbles a 2nd time?

 

[Armor64]

ill look into that as well when i refill the system this friday.

Are these newer systems ok with drilling the thermostat? on my old gmc and my charger i drilled 1/8in holes on the plate to let air escape, but not on this one (yet)
just curious.

thanks all.

 

[tripplec]

OEM stat all I have seen come with a Pin Hole in them. Burping the block after filling is needed (I fill 5the block close before inserting the T-stat and closing it). Pure antifreeze in their then antifreeze with some water in the rad to bring the concentration to 70%. Front end up high on ramps at least, but if the driveway is slopped use that angle as well. It will work its self out running with the rad cap off.

 

[Armor64]

Hi again all. We finally got this thing sorted. Thankfully (for my wallet anyway) it was the radiator having the issue.

After we pulled it out, looking inside at the bottom and there was this white sludge in the tubes. Looks like the previous owners used a leak stop or something and gummed up the works, it wasn't calcium or corrosion I recognized (although my experience is 60s Mopar and 50s chevy)

The only issue we had is we could not disconnect the trans hoses, the fitting were stuck on really well. So we used a wrench, removed the fittings (they spun slowly on the lines so not to hurt the seals) and reinstalled into the new radiator (replaced the orings and added sealant to threads). Refilling, burping, and filling again. It would stay at temp while idle, went for a short loop, the same loop that hit 240, and it stayed frosty at 185-190. Went for a rip at highway speeds, with heat, then ac, then tow haul, reader only got up to 202 max 1 time on the data logger before dropping to 185 immediately.

Thanks so much for the help, ideas, and confirmations.
10/10 will be back for sure.

 

[boominXplorer]

These 06+ explorers do funny things overheating. The radiator fins go up and down instead of side to side and it's really hard to get the air out or keep it from heating up when it's even a splash low on coolant.

 

[Armor64]

Ya no kidding, it was so weird not having side tanks and horizontal tubes, but it made it easier to see the clogs from the bottom at least

 

[michael loibl]

Did u say this 2008 has tow/haul mode?

 

[Armor64]

sorry for the delay, its apparently the O/D cancel, with the dirt on the button, it looked like O/H. but turning off OD would generate more heat, so was still a good test.

 

[michael loibl]

Ok that makes more sence! I was begining to get jealous that mine didn't have it!

 

[tripplec]

Turning OD Off is a must for towing in pretty much all cases. Flat roads with light trailer would be ok but not in heavy tow situations. Owners manual should clarify that as well.