My overheating returned this am. About 10,000 miles ago I replace entire cooling system and still had the overheating, so I put BARRS liquid copper in A/F. Worked good for while, so I flushed cooling sysem with water hose this morning for 1/2 hr., put new A/F and another bottle of the BARRS to see if i can get more miles out of my 5.4. Truck has 272000+ miles on it. I can't figure out problem with it because truck runs perfect, no loss of power or steem. Could my problem be intake gasket or head gasket, as good as truck runs and the fact that i finally got rid of vibration by changing pinion and carrier bearings this week i would fix problem. Truck is a 1999 F150 with 5.4L motor. Any ideas will be appreciated. Thanks to all that give ideas. Is there a good way to check intake and head gaskets to rule one or the other out.

 

Well,....
To keep the engine cool, the pump must work to circulate the coolant through it's system...The thermostat must be working properly to open and close as needed to keep engine coolant at proper temps...
I'm not sure how a stop leak did anything to prevent your truck from overheating as you never mentioned coolant loss issues.....or why you put it in again>?????
If you serviced the coolant system...ensure that there is no air in the system and that coolant if flowing as it should....
...are you having coolant loss????
It is not a complicated system and should not be difficult to troubleshoot.

Let us know what you find....

 

How hot is it? It is only overheating if you are blowing steam. Did you replace the radiator cap and thermostat? Why the need for bars leak?

 

The last time it was pushing A/F out of pressure cap on overflow bottle. I went through 12 gallons of A/F last time ( wasnt cheap), so I tried the Barrs and it run normal, no coolant loss out through overflow bottle pressure cap and run great for about 10000 miles. I have changed overflow pressure cap, rad, fan belt, fan clutch, belt tensioner, both rad hoses, water pump, and heater core, thermastate 3 times, dont think there is any thing left in cooling system. Then yesterday am temp went almost as far as it could go to hot then cooled back to normal and pushed A/F out through pressure cap. Exactly what it done before and I dont want to go through another 12 gallons of A/F, so I flushed system and put 4 allons of A/F and another bottle of the bars. Had now problems when i was driving around last night or this morning. I filled block through thermastate hole and heater core through flush T and then through overflow bottle, so I wouldnt think there could be much air in it. Started it and it run for 20 min and it run over till thermastate opened, filled back up and put cap on.

 

Do you have a weak water pump or plugged radiator? With that many miles and if you've never changed either one, it might be causing the overheating problem now.

 

How much should A/F be moving in over flow bottle mine seems to not be moving really fast, more like a steady slow motion but it will slow down and then increase back to what the steady motion. Like I stated above everything that has to do with cooling system is less than 6 months old or newer. I'm going to change 3 sensors and sending switch for coolant,head, and sender but i don't think it will help if it keeps pushing A/F out of overflow. Changed spark plugs last night, had a good friend that is a mechanic that works for bus garage look at them, he said it didnt look like any had been burning A/F, looked normal but wore out. Plugs had 85000 miles since changed. I average a 1000 miles a week in this truck mostly interstate miles for work. Since i changed plugs and pinion and carrier bearings truck is running great other than getting to warm. The thing that confuses me is that it is not constant, only got hot once this morning, has run fine with normal temp and great heat at heater.This morning had good heat while it was warming up and then it was no heat, instead almost like turned ac on when gauge was normal then thermastate opened and heat returned. Dont know about it till you run it might overheat and might not.

 

It sounds like you have air trapped in the system. From what your saying about the "slow flow, then steady" and also the "good heat, then to cool like A/c" I would have to say you have an air pocket in there somewhere.
Rich

 

Tried to get more airout of it and had alot of bubbles and as A/F went down, I filled it as it was going down and it stablelized after it went down once,I put cap on and had hot air. Let truck cool down and started it and while it was warming up got some heat, but when gauge got to normal setting air cooled off again and then a couple more min it warmed up again. Am I missing something it should not be this difficult to find out what the problem is or get air out of a 5.4L motor. It didnt get above normal on temp gauge or blow any A/F out of the cap, but the air going from warm to cool and back to warm is not the way its suppose to work. All and any guesses might help so please if any one might know how to fix I would greatly appreciate them and thanks to all who leave a comment.

 

i had the same problem last year. you have a cracked head gasket. The bars leak should fix it. I prefer the copper liquid in the round bottle. It mixes with antifreeze and you leave it there forever. If you get another leak, it should fix it on the spot before it gets too big.------ When you loose a quart of antifreeze, you wil get a air bubble in the heater core. the core is as high or higher than the coolant tank. THe air bubble will make the heater blow cool air. I have put a flush TEE in the heater hose at the high point. I use it to flush, and i crack the cap loose when i fill the coolant tank untill all the air comes out of the flush TEE. Your doing good right now.

 

Bar's Leaks Liquid Copper Block Sealer

 

We use K seal with good results on our cat C7 engines that a known for hairline cracks in the water jackets.

 

I put more of the Barrs liquid copper in it after i flushed it out.I had same problem about 10000 miles ago and flushed and put the barrs in it and it worked for a while,but i didnt want to have 2 bottles of it in cooling system without flushing it again.

 

Sounds to me like you have a blown head gasket. Bars leak and other stop leak products will not fix it. They may temporarily mask the problem. But the pressure fromt eh combustion chamber will have no problem pushing and stop leak product out of the way.

Heres what you are going to have to do. You need to drain the antifreeze, then proceed with removing the intake, valve covers, and then the heads themselves, make sure you pay attention to what you are doing and what connects where. Then you need to send the heads to have them resurfaced and cleaned. Then you can put new head gaskets, new head bolts, and replace all the intake and valve cover gaskets. Next replace the thermostat with a Motorcraft one. If you did everything right, your overheating and coolant loss problems will be solved. If it still gets too hot, you may have a plugged radiator from running that Bar's "Clog my Cooling System" Stop Leak in there.

 

I'd suggest a cooling system pressure test and compression test to see if it shows anything.

 

Time to learn a lesson that should have been done the first time.
FIND the cause first instead of doing random things hoping to contol the problem.
Your right back to the original issue again.
Common sense says there are two reasons to push coolant out of the bottle.
1. a cylinder is pressurizing the cooling system.
2. overheating.
#2 come on as #1 pushes coolant out leaving less to cool the motor.
Get a test kit to detect exhaust in the coolant and answer whether it's a head gasket.
A partial radiator block in the ,lower area will cause overheating when under a high load because not enough coolant can circulate and transfer heat to the outside. Then the pushing out begins from overheating again.
None of this is a big mistery.
Then there is a cylinder pressure test that can be done to find the cylinder that is leaking into the cooling system.
Do the work instead of dancing around the outside of it.
If you don't, the truck is not usefull at all.
Good luck.