I understand that if you aren't careful, you can create air pockets in your engine block, when changing antifreeze incorrectly. Of course, air pockets turn into hot spots that can ruin your engine. How do you avoid this problem. What are the tricks?

Thanks in advance.

BillVoyles
RedLowRyder

 

Hey Bill, Had the same question a couple of months ago and ultimately decided to take it to jiffy lube where they have this cool machine that drains the old stuff and fill with new at the same time.

 

I don't know of any tricks as you say, I just stuck a garden hose in the overflow container, opened up the drain on the radiator and let it flush untill clear came out. If there was one trick that made the job a little bit cleaner, it was putting a length of 1/2 inch hose on the drain so I could collect it in the bucket better. Don't sweat it, just remember, that thing was bone dry at the factory and they filled it up ok, without burning it up. I don't think the engine will lose it's prime so to speak unless you yank the block drain. When you refill it up, just put in the 2 gallons of antifreeze, top it off with water and let it do the mixing. Your mixture ratio will be ok if you know the capasity and follow the mixture directions. Also, only use of the same color ie...green, replace with green, pink,,,replace with pink and so on. That will keep you out of trouble.

 

Check in the manual to see if there are any block drains. If there are you will need to open those up during a flush. When you fill it back up, constantly squeeze on the radiator hoses to act as a pump. When you have enough in there, start it up and continue pumping the hoses and topping off for as long as you can.

 

Forgot to mention....

I have well water that is just filled with iron and other chemicals that I wouldn't want inside my engine. It can turn into hard deposits over night. So, I can't use the garden hose method.

But, I thought of a trick, if you want to call it that. I saw distilled water at Wal Mart for 77-cents a gallon. As you drain the radiator, you could fill the overflow tank with distilled water until it runs clear out of the radiator valve. Then, you can dump in a can of Prestone Flush and run it for the recommended time, and follow the same procedure of draining and filling with distilled water until the flush is all out of the engine. Then start pouring in two gallons of the correct (color) antifreeze and when it has taken both gallons....close the valve on the bottom of the radiator.

This method will keep air pockets from forming (I think) and would keep the new water 100% pure. What do you think?

BillVoyles
RedLowRyder

 

A lot of owners are nervous about changing their own antifreeze because they are worried about trapped air. It's not too complicated as long as you use common sense. It just takes a bit of time because you need to go through the warm up and cool down cycle a couple of times.

My '97 4.2L holds apprx. 5 gallons of coolant. Costs about $30.00 to change it yourself and if you are mechanically inclined then you know it was done right. I personally don't want anyone working on my truck but me.

You'll need:
>3 Gallons of coolant
>6 Gallons distilled water
>1 can of radiator flush
>Large container for mixing
>Large container for collecting drained coolant

When you have everything you'll need to:

>Add the system flush and drive until you reach normal operating temp. (I can't recall the specific instructions but I left mine in there for 2 warm up cycles because I couldn't get the block drain bolt off. The bolt is 1/2" square so turning a 3/8" socket around and putting an allen socket in there and then attaching a driver worked for me)

>Allow the system to cool to a point that you won't be scalded by the coolant and remove the recovery tank cap and radiator drain valve and allow the coolant to drain.

>Next: flush the radiator with water from a garden hose till it runs clear and replace drain valve.

>Crawl underneath and remove the engine block drain bolt/s. (I could only find 1 on my engine but all of the coolant came out)

>When all of the coolant has drained, run water from the garden hose through until the water runs clear. (When I flushed mine, all kinds of crud came out and I don't know that flushing through the lines with the machine would have gotten it all out because it was settled at the bottom of the engine block)

>When it runs clear, run a few gallons of distilled water though. (Cheap insurance you make sure hard water deposits aren't left behind) Replace the drain bolt with teflon sealing tape.

>Add coolant at the recovery tank till it's full. You'll probably get 2.5 gallons in.

>Leave the cap off the recovery tank and start the engine and turn the heat on it's highest setting and go back to watch the recovery tank as the engine warms up. When the thermostat opens, the coolant from the recovery tank will be pulled into the engine coolant passages. When this happens, turn the engine off and let it cool. After it's cooled, add coolant again until it's at the full mark and squeeze the upper radiator hose to expell air. When you squeeze the hose, you'll see water bubbles come up in the recovery tank.

>Repeat the warm up, cool down procedure until all the air is out of the system and the coolant level stabilizes.

 

The smart money is on taking it to the dealer where they can deal with the proper disposal of the old antifreeze. In many, if not most areas of the country, it's now illegal (not to mention dangerous) to just let it drain down the driveway.

 

In some places you can dump it down the sink, some auto parts stores will accept it, any HAZMAT collection facility will take it and I have also seen land fills that accept it. Where I live, if you leave your oil with your trash, they will collect it and have it recycled, not sure about antifreeze.

 

I work at a new car dealership, amazingly enough we don't have a power flush machine so this is how we do it.

-Remove the radiator cap

-open the radiator drain and block drains (don't open the block drains if they appear rusty because they may not reclose!)

- remove the expansion tank from the vehicle and wash it out.

- close all the drains and fill the radiator with a mix of coolant and water.

- take an old cv boot and stick it in the radiator neck (this isn't mandatory but avoids making a mess when the coolant heats up and overflows)

-turn the heater to hot but leave the blower off.

-start the vehicle and get it up to operating temp, i usually stick a screwdriver into the throttle linkage to hold it at about 2,000 rpm.

-as it runs the air will work it's way out, when the cooling fans kick on (if there electric) bring the engine down to idle speed. As the coolant temp declines it will suck down into the radiator, keep topping it off.

- When the level stops dropping cap the radiator, fill the expansion tank to the full mark and shut the truck off. after about 10 minutes top off the expansion tank and you are good to go.

-Jon

 

This the method I use .

1. Have a couple friends help you because you need to do this within two minutes . You will need a few floor jacks to avoid running back and forth .

2. Block your wheels and position the floor jacks to jack up the front end .

3. Drain old coolant into a catch bucket and reinstall the drain plug .

4. Pre Mix coolant and water to a 1:1 ratio . Fill the radiator to the top with the mixture and leave the radiator cap off .

5. Start your engine in park and leave it there or set your parking brake and and leave it in neutral .

6. Quickly , as your truck warms up jack the front up and leave there for 10 seconds . Let the front down and jack up the rearend and leave for 10 seconds . Let the rearend down .

7. Repeat as necessary .

8. After 2 minutes , remove the jack(s) and fill the radiator, install the radiator cap and fill resevoir to the correct level .

9. Done

The rocking motion will ensure any trapped air will have the oppotunity to escape .

After all of this tire rotation will be easy .

 

kinda like changing a light bulb by having two buddies turn you while you stand on a ladder? I understnd perfectly

 

LOL, that is an interesting way to do it. I'm not sure what I would think if I saw someone doing that to their truck though.

 

Yes, trapped air is something to worry about - it happened to me. On the L, I was drilling and tapping a hole in the water jacket for my mechanical guage NPT sensor and the temperature sending unit, and to install electric fans. Before drilling the hole, I drained as much water from the overflow tank as possible via a hand pump siphon. After installing the guage, I filled the overflow tank back up and let is sit for 15 minutes or so to let the air bubbles out, then topped off. I started the engine in the garage and let it idle to test the guage. The guage needle moved and stopped at 185, the thermostat setting but would not go further which was strange to me because I had set the "fan on" to 200 and the gauge was not moving past 185. I continued to let the engine idle, when it suddenly started "missing" very badly. I immediately shut it down and walked to the front of the engine. Needless to say, my rear was puckered up pretty good. All appeared, OK (no boilovers BTW). After letting things sit for 15 minutes, started the engine and it ran fine, but a check engine light was on - I was thinking that I had screwed the fan wiring up and had a ground fault somewhere in the system. Shut it down and cleared the code by cutting out battery power. Restarted the engine, all was fine, and went for a test drive. During the test drive, I kept my eye on the mechanical temp guage. About 100 yards down the road, the temp needle started moving very rapidly from 185 to 220. I was about to shut it down in the middle of the street when the needle dropped just as quickly back to 185. When that happened, I realized what happened - air trapped in the system and it had just vented when the needle dropped. Earlier, when the engine was "missing", it had reached the preprogrammed fail-safe mode, where every other cylinder fires to reduce combustion and water coolant temps. Nice safety feature.

BTW, I had to do this again a few days later to install a new water pump. This time I drove the truck immediately instead of idle in the garage (keeping an eye on the guage). This worked much better and any trapped air dispursed normally.

Boy did I feel dumb, but fortunately no damage was done thanks to the safety feature. Also, my other cars had an air bleed off valve for this very problem. I was stupidly thinking that trapped air was not a problem for the F-150's since there is no bleed off valve. Live and learn.
GDG