Ok, Let me give you a quick rundown of my issue, and what ive tryed to do so far to correct it... 1994 Ford ranger, 4.0, 4wd, 5 speed, NO a/c.. Nothing to fancy.. Going down the road the temp guage will fluctuate (sp?) from the lower end of the "Normal" range to about 3/4 of the way towards "Hot"... Truck Has 215k on it or so... So far I have changed the coolant, old stuff was kinda gross, sorta turning brown, water pump has been changed Thought maby it was a stamped steel impeller and was missing fins or something of the such.., intake gasket has been changed, I was dooing some exploring to make sure the passages were open and not glogged, they looked fine, small amound of gasket deterioration, and small seem from front coolant port into the outside world.. each step of the way i put in a new thermostat... Just hoping my magic wand will work.... when "burping" or purging the air out, if you fill it with the hose from intake to heater core on, it purges air violently, like its boiling water and it explodes into the radiator... if you pull that hose off and fill it till the coolant comes out to the end of the nipple, and cram the hose on, it seems to not boil internaly........ ive also flushed and backflushed the radiator and heater core with a garden hose... no success.... I am compleatly baffled here.. any ideas are awsome, it almost acts as if its still air bound, ive tryed to fill it with an "Air-lift" system, with no luck... This is just so far off the normal diesels i work on, ive never run into this before, so Ideas???? Good ill take them. Thanks Guys!!!!

 

Several things. Ford had a problem with the original impeller design, they came out with a new updated design that fixes the issue. Most aftermarket pumps copy the original incorrect design. Most aftermarket thermostats are worthless. I use the genuine Motorcraft ones, thats the ones ones that burp correctly, and open and close at the right temperature consistently.

Id does not seem you are following the burping procedure.

What you need to do is first fill the system. If you have the entire front of the vehicle lifted up, that helps. Make sure you only fill it with pure antifreeze and water, or premixed, no tap water should be used. Tap water causes corrosion in the cooling system, but in the short term, the minerals in tap water also alter the boiling points slightly. Once it is filled, squeeze the upper hose a couple times to purge any air trapped there. Then fill the reservoir to the max line. Make sure the overflow tube has a good seal, otherwise air gets sucked into the system at cooldown. Put the radiator cap on, but do not fully tighten. Notice the cap has multiple positions. It has a looser setting, this is used for purging the air. You put that on, warm the engine up, then run it at 2000 rpm with the heater on full blast. Then let the system cool back down and check the fluid level again. Refill and repeat as needed.

 

If you'll raise the front end, or park with the front end uphill, the steeper the better & run the warmed up engine with the heater temp control on High temp for a few minutes, to chase any trapped air toward the radiator, then turn the engine off & let it fully cool, a properly working radiator cap & properly filled overflow tank, will let the cooling system burp the air out & top itself off when it cools. When it does, you'll notice the overflow tank coolant level drop, so top it up & repeat until the overflow tank level doesn't drop anymore.

A Ford thermostat, or one like it, that has the air bleed valve design, will help in filling & burping the system. I've also pulled the heater return hose loose at the firewall, as it's a high point, it'll help purge air on a refill.

With the pump impeller blades being eroded I might be worried that pieces of it may be lodged somewhere & causing flow problems, so maybe they've made their way back to the thermostat & are messing with it.

Because of mineral & chemical additives in tap water, it's not the best choice for a cooling system refill. Distilled, or DI water is better by far & is avaiable for a reasonable price at WallyWorld.

Be careful not to overpressure the cooling system with the garden hose. House psi is about 60 psi, the cooling system is about 15 psi, so we can pop a gasket, hose, radiator, or heater core, if we run the garden hose wide open & over pressure the system on a back flush, or refill.

More thoughts for consideration, let us know how it goes.

 

The original water pump was fine, cast pump impeller. And that fill procedure is the same as the one in Mitchell. Straight from Ford I'd think. Motorad thermostat with bleed port in it. I'm almost thinking someone put some leak stop in it or something. Lost heat this am. And flushed heatercore and brown sawdust looking crappy was in it... Im wondering if there's some in the radiator. Maby the radiator needs go to the radiator shop....

 

Unless you have a vintage vehicle with an unavailable radiator, no point in repairing the old one, just replace the whole radiator. You of course need to have a pretty good idea that it does need to be replaced first. I recommend Performance Radiator brand. They have never let me down, and they are true to their name. They have better cooling capacity than most other radiators.

 

ATC_250SX, if you clean or replace the radiator, do the same with the heater core. More of that stuff you found is probably in it as well. Some of the newer radiators like yours are not easy to have cleaned because of the plastic tanks they have and the tabs that hold the tanks on break easy when they are being taken apart. They're kind of like a throw-away part. Just replace it with a new one.

 

Ok, well I think that's what's in order, I did a coolant backflush to it at work.. and got a lot of crappy out. Its better now but not right still. And with a radiatior only costing 105 bucks. I'm just going to order a new one. The radiator shop was 55 with no promises of repair...... ill let you guys know how it pans out.

 

I'm running a new "Ready Rad" radiator from Advance Auto in my 94 Taurus, after the replacement OEM ones drivers side plastic tank developed a crack about 4 inches below the hose fitting, due to a molding knit line flaw. Second flaw for the Motorcraft radiators, as the OEM one developed a leak in the lower left aluminum tube portion under warranty & was replaced by the Dealer, so imo Ford radiators don't have the corner on radiator quality or replacement cost!!!!

The Ready Rad has been in there going on 4 years now, no problems so far. Nice piece of work, everything fit like the factory one & it was in the price range you posted above, so maybe it could be on your shopping list choice too.

Good idea to back flush again, seeing as how you got so much sediment out of the heater core. Too bad the cooling system has gone neglected for so long & the second back flush didn't completely clear things up.

Seeing as how you've gotten so much sediment out on the back flushes, I'd probably opt to pull & inspect the thermostat again before replacing the radiator, just to make sure it's not clogged up.

Maybe consider replacing the radiator cap & all hoses too, if they've never been done.

I completely redid the Taurus cooling system while I had it open, new radiator, heater & engine hoses, radiator cap, thermostat & new ASC Signature Series water pump, another fine piece of work, as the replacement Motorcraft pump had just developed a drip at the weep hole.
The hoses were OEM, felt & looked ok on the outside, but were just beginning to show some very fine cracks in the inner tube lining surface, when flexed, but the very fine cracks weren't all the way through, just surface checks, but non the less an indication that I had pushed their service as far as I dared.
SO, the Taurus radiator cap, thermostat & hoses have been replaced with Motorcraft, as they've given flawless service.

Have you used a good flush chemical product like Prestone, etc., to remove scale & rust during your back flushes???? If not, I'd consider doing that & back flushing again, before installing the new radiator & heater core.

Will be interesting to hear how the new radiator & heater cores perform.
More thoughts for consideration.

 

Paw Paw, Thank you for your input, I did not call them yet.... Shame on me, I just priced what I had available from the shop I work at, Wich was an SPI Brand radiator... Now I just need to find if its a heavy duty cooling or not.. I think it is, but cant hurt to put in a bigger rad. anyways for less than ten dollars... And both flushes were done with a "Cleaner" and then flushed, just like a BG, Runrite, QMI.. etc. That you find in many shops and dealers.. Oh the joys of a shop that pushes "Schedualed Maint." and your right i wish the owner i bought it from did Just a little maint. other than oil changes.. But then again... I may not have got it for such a good deal...

 

I have had the same suspicion with my 94 xlt ranger supercab, as I have recently went on a vacation and ive been have the problems i even purged the air multiple times and when i fire up the truck with out the cap on it spits it out even when cold. im also under the suspicion that i might have a cracked cylinder wall as mine has 215k+ miles and had done the heads at 214k+ miles.