I did this same job on my 84 6 cyl with A/C about 8 years ago. Had to take the glove box apart to get to the core but once there it was easy to remove and replace. What was hard was getting me into the tight space under the dash to do it all. Core was $45 at Car Quest and 8 years later no problems. The job is a PITA but I had driven from northern New Mexico to Grand Junction one March day with no heat and just about froze. Now it is toasty when I need it and no window fogging from coolant leaks.

Jim Johnson
Chandler, Az

 

One last thing (although looking at this thread, I'm sure I'll have another question), does it matter what kind of water I do the actual flushing with? My hose water comes from a well and goes through a softener. I'm asking this since I know that it's important to be topping off the system with -distilled- water.

 

No, regular well water is fine to flush with. Also, The little bit of well water that would be left wont hurt anything either.

People have used regular well water (instead of distilled) in their vehicles for years, with no serious ill effects. My Grandfather etc...

I don't recommend it because of the minerals that could be in the water. Could lead to calcification of the passageways etc. Simular to a shower head.

 

A three page thread just for my one simple question... who would have guessed? Hah, well, I got more now. I'm going to (finally!) flush my system and put in my new heater core on Wednesday of this week. I'm making sure I get all of this right before I go about doing it so I don't jack up my truck. So in order to do that, I've been checking other how-tos about this and stuff, and...

They all say to do it a different way.

Is water alone enough to do this? A few other places have said I should buy radiator flush and run my engine until it gets hot and drain it like four times before I put any new coolant in. Other places said I should brush my radiator and pick out all the dirt. From what I gather from this thread, all I really need to do is just drain the coolant, then just hose in water through one of the coolant holes in the side of the engine. Which is right?

Also, should I have my engine running at any time during this process? I heard that pouring coolant into a cold, turned-off engine can damage it. I also heard that it needs to be running for the water to clean the gunk out.

I guess what I'm asking for is a good, solid, step-by-step list of directions from someone here on how to do this right. I'm sorry for dragging this thread out so long, I just don't want to do something wrong and ruin my truck. I barely have time to do this kind of job myself, and around where I live, a garage might take a week or so to get this done, so this is really my only option. Besides, there's nothing like teaching yourself (with huge amounts of help, of course) a useful skill like basic mechanics

 

I have owned and worked on many vehicles through the years, and this has been my experience.

If the vehicle and the coolant has been well maintained, then everything will be fine, and it really will not do much good to flush it, though it won't hurt it either. I have run into vehicles that I did need to flush 3 or 4 times, but you will recognize these right away, since when you drain the coolant out of the radiator, if it will come out at all, it will be like brown syrup. These are the ones you have to work with for awhile.

So with a cool engine, I would drain the coolant and see what it looks like.

If it looks good, and you still want to flush it, then take the lower radiator hose off the radiator and put it in a pan or bucket as best you can.

Take one of the heater core hoses off the engine, and stick the hose up in the end of a garden hose, and turn the water on.

More coolant should start coming out of the lower radiator hose, and after awhile it will clear up. Then you can stop.

Put everything back together except the heater core hose, and then fill with 2 gallons of anti-freeze. Keep and eye on the heater core hose outlet on the engine, and when coolant starts coming out of the outlet, stop and quickly put the hose back on. This will help get a lot of the air out of the engine.

Continue to fill the radiator, and when it's almost full , leave the radiator cap off and start the engine.

As soon as the engine starts, the coolant level will probably drop. Pour some water or coolant(whatever you have left, make sure you get the whole 2 gallons of antifreeze in) till the radiator is half full, and let the engine warm up.

As the engine is warming up, the coolant may rise and puke out of the radiator a little bit. This is the air burping out of the system, and does make a little bit of a mess. It will finally settle down, and the upper radiator hose will be hot, and the coolant will be rushing by the top of the radiator. When this happens, fill the radiator to the top, put the cap on, and then fill the overflow tank about halfway.

 

Alright, that sounds like something I can do for sure. Thanks to everybody who's helped out on this thread, I guess changing the coolant is one of the simpler things that one can do to a vehicle, but it's my first time and I wanted to make sure I do it right. I'm glad I've found a community that can help me out for all of my home-"mechanic" (if you could even call it that) needs!

 

try to avoid the crimped on style hose inlet tube type heater cores as they are known to fail shortly especially where the fire wall adversely effect them.

 

When I said heater hose in my previous post, I meant the end at the engine. Never mess with the heater core side of the hoses if you can help it. If you need to change out the heater hoses, then carefully cut the heater hoses off the core at the firewall, never twist and pull on them. I have learned this lesson the hard way, and changing out leaking heater cores is no fun. I have even started them leaking by accidently leaning on the connection with my arm while doing engine work.

 

So I get my glovebox out, and there are two visible nuts out of the eight or nine I should see. You guys were right about the PITA thing. Unfortunately, due to lack of tools and time, I'll just have to suffer another cold winter. Not good. Total confidence buster, so now I doubt I'll ever get around to doing anything to my truck.

 

It's not really that hard and I would definitely NOT give up so easily on it. If your winters are anything like we have here in PA, you will appreciate the extra effort now and your toes will thank you.

Once the glove box is out, you should be able to reach most of the bolts. IIRC, there is one up under the passenger side inner fender that needs to come out from the engine compartment.

Stay with it. Don't quit!

 

I agree with stosh, all the rest of the screws are accessible from the engine compartment.

The job can be done with a small socket set.

 

I was on my way of removing my heater box from my 1981 during my recent engine rebuild,
but I found there's a *nut* that's apparently accessible only by removing (or at least
loosening) the cowl panel! I first thought a PO had assembled it that way but, no, the
factory did that!!! I'm used to Ford using those clip-on sheet metal nuts so that you need to
access only the one side of the bolt with your hands & tools, but I guess they deemed this
was satisfactory for some odd reason.

I'm assuming we're talking non-AC here; if not, nevermind. ;-)

-ct

 

My 1981 is not like that. What month was it built? Mine was built in 11/80 and is non A/C.

 

Maybe I was a little rash. I'll give it another go, probably around the same time next week. I was just a little frustrated because it seems every time I work on my truck, I find something else the previous owner did that shouldn't be there. Cut plastic, new parts, mysterious wires, stuff of that nature. Anyway, how accessable are the bolts on the cab-side of the firewall? I took out my glovebox, but I could only see two. It really looked like the dash needed to be removed, but like I said, I'll give it a go again next week or so. Hopefully it wasn't something the guy before me changed (although the heater is one thing that looks like factory original). Thanks again

 

Adding to the mix when you change out your heater core see if you can find a aluminum heater core.They put out more hot heat than the copper ones do.