zuric

Posted this over on general, then read about the specific year area;

Ford F-150, 2000, 4.6 Engine. 187,000 miles. Planning a trip to Yuma.
Truck was running well, needed some PM's. (fan clutch rattling,hoses cracked,that sort of thing)
Replaced; Water pump, upper/lower radiator hoses. Thermostat, Fan Clutch, used Prestone radiator flush, cleaned system with distilled water, about 12 gallons worth. Hosed off radiator finns, replaced anti-freeze 50/50 Prestone green.
Truck will heat 3/4 way up gauge at 60 mph, A/C running. A/C will cut off, truck drops back to normal. A/C cuts on, truck heats. At 30-40 mph, no problem.

Replaced thermostat, another water pump, another fan clutch. Bled system repeatedly. Dropped antifreeze mix from 35 below to 20 below.
I am missing something here..anybody got any ideas ? Thanks in advance for ANY help...

Drove it again today, about 20 miles. 18 miles normal, then gauge moved slowly to 3/4.
A/C on Max from start, 84 degrees air temp. Stopped, temp started falling immediately. Top hose 190, bottom 170 by remote thermometer.

Btw, I also changed the idler pulley, serpentine belt and overflow cap.

mbb

How actual temp off a scantool? 3/4 dont mean a lot.

Can probably rule out tstat, water pump, fan clutch.....
For future ref, fan clutch will only effect at low speeds. At hwy speed, no effect.
Water pumps are rarely an issue for lack of cooling.

Whats left?

Radiator clogged
Cooling passages fouled
Bad ect sensor
Low coolant
Circulating gasses

The fact ac affects engine coolant temp significantly indicates marginal cooling . So theres likely an issue.

What coolant was specified for your truck in manual? Gold or premium green?Mixing wrong coolant at some point will F up a radiator. Its not easy to flush parallel path radiator either. Actually, its not possible. I wouldnt use prestone anything personally. Ive seen really messed up cooling systems with prestone. Not sure how they got that way. Full of white solids.

If your sure, no hg leakage into coolant, and right level, your next step is likely a new radiator. They are inexpensive. If your radiator is fouled, your heater core is probably plugged. Hows your heat work?

Did. This only start after you did initial work? Or before?

Jbrew

Sounds like the wrong T-stat IMO...which will totally flip everything out. Not a bad T-stat, just the wrong one, - out of spec.

Good Luck.

mbb

Isnt 4.6 difficult to burp to get right coolant level?

Was it burped to get air out system after refill?

Trapped air circulating would give exact symptom probably

zuric

"How actual temp off a scantool? 3/4 dont mean a lot."
Yup, however, Ford didn't see fit to put anything but a sweep gauge with "blown engine" on one end, and "freeze to death" on the other.

The heater core was replaced a couple-3 years ago, blows nice and hot on these 90 degree Ozark days..one of the procedures used to burp the system. Water was added over several days, then is stabilized. no change in heating. Have a flush valve in the heater hose, have filled it full with over flow cap in place.
The new radiator is on its way, ordered today. It is indeed possible I suppose that the process of flushing it finished off the radiator. Also ordered a new ECT.
Have replaced the thermostat twice with 195 degree units..supposedly OEM temp.
Had ABSOLUTELY no heating problems previous to work being done..and I use this truck with an 18 foot foot trailer to haul cars around, etc...

zuric

Green coolant is recommended, and so used. Prestone. Been using it in this truck since I got it 12-13 years ago.

white89gt

I've done it twice on my F150 and once on my Expy (both 4.6's) and had zero issues with air getting trapped. However, I do mine probably a little different than what most people do. Rather than fill it through the overflow bottle... I fill it through the top of the radiator. This has worked out great all three times.

Jbrew

They are also notorious for trapping air right under the ECT sensor on some models (brass bulb that should be cleaned by hand when flushing) if your cooling system has one. You burp that out by cracking the ECT , like you would to purge diesel injector .

Other than that, this will usually work, -

zuric

"brass bulb that should be cleaned by hand when flushing)" "ou burp that out by cracking the ECT , like you would to purge diesel injector . "

Good God !! Mayhap a lil blanky and a few pats on the butt would help ?

Well, never heard that before, but that is EXACTLY why I posed the question to all youse guys..somebody, somewhere, somehow has seen it all..tomorrow I go back to burping the baby. Won't get the radiator till Wednesday, so trying something else will occupy my time.
Thanks, fellers, for the input !!

Jbrew

Hahaha, well give it shot if you think it's trapping air. Before Ford deleted the ECT all together (they went to Dry Socket "CHT" vs Wet "ECT") they re-engineered the ECT adapter for two reasons. The original design would corrode at the cold climate system T and break off (if your vehicle had the CCS, some did not). The other reason was that the adapter sleeve and ECT together were too tall creating the hot spot at the sensor. It would take too long purging itself out. So they made the sensor and sleeve one piece making it shorter and added a much beefier CCS T that was no longer made off steel.

Anyway, that's all you have to do, crack them quickly then tighten it back up.

Also and with age, the block/system becomes chucked up with corrosion, shards that break off and trap in the system. One of the first things to do is pull the block plug. If you don't and when flushing, you'll send daggers and metallic chunks throughout the coolant system and you get partial blockages, HC, HG compromise etc.. If I didn't pull the BP first when maintenance the coolant, there's no way my engine would have made it to 348,000 miles. No way would I still be using the factory original HC on that engine. Pull the plug on some of these engines and you would believe how much crap is the bottom of the bucket lol. Sounds like your doing things correctly, or want to.

Good luck, hope this helps.