With a 1985 6.9, thats a 28 year old truck! i picked it up less then 6 months ago from a field in non working condition and have since brought it back to life. I am going to be changing the coolant out and was wondering what you guys would do as preventative maintenance while i have the coolant drained.

Although i am cheap i am restoring this truck for me to take to college in the fall. I dont mind putting money into it just as long as it is money well spent and will make the truck more reliable and safer for me to drive on the road.

Water pump?
thermostat?
coolant hoses/lines?

Would you bother since everything seems to be working?

thanks!

 

I generally tend to not fix it if it aint broke, but I'd do hoses if the old ones aren't pristine.
I'd also take the belts off and spin the water pump by hand to "feel" the bearing, and see if there's any slop. I'd probably do the thermostat. (that one's too much of a temptation for Mr. Murphy...)

 

I agree I would change the thermostat. I would also do a really good coolant system flush. When you replace the coolant be sure to use coolant with the proper SCA's. A coolant filter is a good add on that will help protect your coolant system. A water pump isnt a hard job to do, but im sure that there are more pressing issues if yours is working properly, like the fuel injection system...

 

note that if you do change your thermostat, ONLY BUY MOTORCRAFT for that. anything else won't work right.

as for coolant, 7.3s need a coolant with SCAs - an additive to prevent cavitation, which is a nasty problem. you're in a 6.9, so while its not required it is wise to have. do a search and you'll have plenty to read on the subject.

if it were mine at this point, i would probably just flush it out good and roll with it.

 

all diesels, no matter who the manufacturer or engine size, require some type of SCA in the coolant.

 

Not to be a pessimist, but the main thing to keep an eye on is basically everything else in the system after you get the work done. The process of draining, flushing, cleaning, and filling the system will often expose another weak link in the system. For me, it was the radiator, which has led to a bunch of smaller issues. Not saying you shouldn't do the work, but be prepared.

To do a thorough job of getting all the old stuff out, pull the drain plugs located on either side of the block. Many replace these with pet***** to make the job easier the next time, though I didn't find removing them to be a big deal.

Mike

 

I use Wixcool . An add on coolant filter would be nice .

 

Mike would you mind listing out the steps to draining the fluid on a 94 idi turbo? seems easy, but i always like to be prepared. if you dont feel like listing the steps, I was wondering if you could pinpoint where the drain plugs on the block are. Thanks !

 

Don't know if it's any different for a factory turbo (wouldn't think so), but the gist of it goes like this:

1. Let the system completely cool, like ice cold.

2. Remove rad cap

3. Drain radiator.

4. Drain block by removing plugs (one on each side). IIRC, they're 9/16" head hex and look like a bolt sticking out from the block (brass). The driver's side one is kinda near the oil filter; the passenger side plug is basically in the same spot on the opposite side.

5. (Optional) Plug everything back up and fill with a mix of water (tap or distilled) and whatever flushing agent you choose. There's a bunch of different stuff on the market, and even more 'old tricks' like dishwasher detergent. Run the flush for however long the instructions say. Some recommend idling in the driveway for a bit. Others recommend running with the flushing agent for a week or so. Just know that if you live in an area that can freeze, a lot of the flushing agents don't contain any sort of antifreeze like you'd normally run, so plan accordingly.

6. (Optional) If you're super ****, re-fill with tap or distilled water to flush. Repeat as many times as you feel necessary. The color and condition of th6 fluid coming out should be your guide.

7. (Optional) Pop the hoses off the heater core and flush with tap water. If it acts like it's backed up, now may be a good time to replace.

8. Drain everything again

9. Now'd be a good time to replace whatever it is you're going to replace since the system is empty (e.g. hoses, thermostat, heater core, etc).

10. Fill 'er up with whatever coolant you choose, but make sure it has some sort of provision for SCAs to prevent cavitation. I use FleetCharge because I can buy it locally at O'Reilly and I mix it with distilled water. You'll need 4 gallons of coolant (mixed with 4 gallons of water for 8 gallons total).


Filling the system can be a bit of a pain because you need to have patience to wait for the thermostat to pop open. There are techniques to get around this (like filling the block through the heater hose nipple or the thermostat opening), but I do it the easy way. Close everything off, then fill the radiator until the cores are covered (should use about half of the 8 gallons). No need to fill it all the way because it'll burp itself and inevitably make a big mess. Now fire it up with the rad cap off and wait..........and wait......and wait. Seriously, this can take a while. But eventually, the coolant level will start to drop and FAST. Keep the rad more or less topped off (at least have the cores covered). You'll get a lot of 'burps' from the system coming through the rad cap opening. This is perfectly normal. Once they stop, top off the rad and pop the cap on. Throw some coolant in the overflow tank (about 1/3-1/2 full) and you're done. DO NOT TAKE THE RAD CAP BACK OFF UNTIL THE SYSTEM COOLS OFF NO MATTER WHAT!! Even if you 'just' put the cap on, the system will pressurize almost instantly. Nothing like a boiling hot coolant geyser to ruin your day.

Some would tell you to drive the truck a bit to speed up the wait for the thermostat. I don't recommend it if you drain the block because you're essentially driving around with the system only half full. It'll overheat in no time. I got impatient with mine and tried to do that. I made it to the end of my block before the temp gauge spiked. The thermostat had opened and the radiator had completely drained itself into the block in just a minute or two. Instead, I recommend waiting it out. If it's real cold where you are, throw a piece of cardboard over the radiator fins to help speed it up, but otherwise just be patient.

Mike

 

my rules on this part are a little more lenient. if you intend to remove the cap, first squeeze the upper radiator hose with your hand. if its soft, theres no pressure and its safe to open, but still be careful. if the hose is hard, allow it to cool until the hose is nice and soft. it'll usually be ready by the time its cooled 10 degrees from whereever it was.

 

splendid! so i have decided on doing the thermostat and heater core but im not sure about the water pump. whats the deal with that? how would it go bad? are there seals that go bad and it starts leaking coolant or does rust in the system just take out the fins of the pump over time and then it spins but cant pump the coolant? if my system is not very rusty at all would that be an indication of everything being fine and dandy and maybe i dont have to worry about my pump going bad for the next 100k miles? The green coolant that the truck came with seems pretty clean just by looking in the radiator cap....

 

water pumps can fail usually either in the bearings or the seal, and result in leaks from the pump itself, or occasionally seize up. if a $60-70 pump fits your budget, it might be a good idea, especially since your truck sat for a long time without being used

 

Water Pump | 1985 Ford F350 1 ton P/U 4WD 8 Cylinders 1 6.9L Diesel | AutoZone.com

duralast new vs valucraft remanufacturer? with a name like valuecraft.... lol

 

I got a Gates pump brand new from Rock about for 37 bucks and shipping. Most rebuilt parts are done by replacing whatever is wrong with it, and the rest is left untouched. I try to buy new parts whenever possible.

Mac.

 

I'd go even further, and remove the rad from the truck, it'll be alot easier to play around with it, flushing it out every direction possible, and pressure wash the fins area to get all the crap out of them.


You say you don't mind investing abit of money into, as long as it goes for something good, well then re-do the entire cooling system. I did it in my van not long after I got it.


I had no real history on it, and I go on long trips with it, and I personally like piece of mind instead of carrying a ton of parts with me.


I flushed out the rad and block, did the water pump and thermostat and hoses. The thermostat looked nearly new, but replaced it anyways and kepted the old one as a spare. Also installed a real temp gauge!




My '94 F150 I bought a while ago as a winter truck, I also re-did the whole cooling system.... (rad, hoses, thermostat) except the water pump, and well, it left me stuck overheated on the side of the highway on the coldest day of the year, -15*F at 7am heading to work. Water pump failed.



Just because is working fine now... doesn't mean it's any good for god knows how long.