My '93 5.8L XLT goes through coolant like crazy. At least twice a week I have to re-fill the overflow reservoir, after about 100 miles in maybe 5 trips it's bone dry again. It doesn't leak a drop of fluid, nothing in the cooling system is wet or indicating a leak may be present.

I was thinking the cap may be *somehow* worn out and leaking steam slowly, though I never notice or smell this. Also, right after I fill the tank, drive it until warm, the fluid in the tank went from the clean 50/50 antifreeze/water mix to a dirty, kinda rust colored. Figured I should plan a flush soon, maybe this weekend.

And the radiator cap is listed at 13lbs. Would this be too weak causing a pressure leak? The truck never overheats or even runs above what it always has. Highest the gauge goes in daily driving is the "O" in "normal", will just touch the "M" in towing or a load.

 

Do a compression test........

 

Are you sure it's not the heater core? That leaks behind the R front tire, and it blows/evaporates away almost instantly as you drive, leaving little evidence by the time you get out to look.

I wouldn't do a compression test - I'd do either a pressure test, or a dissolved-gas test.

13psi is correct. The gauge is just a gauge - it's not a thermometer, so you can't tell anything by where the needle sits. Its purpose is to show you any CHANGES.

 

i think you can rent a pressure test kit from advance or the zone, i dont have one but i dont think they are that pricey

 

When my heater core went, it was leaking inside the cab on the passenger side. There was no doubt it was leaking though. You couldent miss it between the puddle of coolant on the passenger side and that nasty coolant smell. I hate that smell.

I guess there is more then one area where the heater core leak shows up depending on where the core itself is actually leaking. But I was just throwing this out there.

 

That's just the thing, I don't smell coolant at all so I kinda ruled out the heater core. Also, it's parked in a smooth concrete floor garage, so any leaks easily show up on the floor. The heater works almost TOO well, as in unless the temp **** is a max cool on VENT mode, you get hot air out of the vents. Think there's some rotty vacuum lines behind that.

To try it, I drove normally until the engine was at normal temp, then parked it in the garage and left the motor idling in Park for a good 5 minutes with the heater on max. Looked (and sniffed) around, didn't notice or smell anything out of the ordinary.

The coolant is really dirty and I plan on flushing it this weekend. Where would the drain plug be on this motor's radiator? I looked around, but didn't see anything offhand. Seemed a plastic shroud thing was covering the bottom of the rad, would that have to be removed?

The Hayes manual also says that a "flush additive" should be added after you drain the coolant and refill with plain water. Then drain the water+additive, and refill with fresh coolant. Any suggestions on this? The manual also specifies a 15lb cap, which is why I originally thought the cap may be leaking steam.

Are any of the stupid Ford gauges real? They might as well put stickers on the dashboard for how useful they are. The oil pressure is fake, the coolant is fake, and the gas gauge is really, really in-accurate.

 

use distilled water mixed with a good antifreeze, and replace the cap, and any hoses more than 5 years old. it sounds like your Thermostat is good.

check the hose and connections from the radeator to the recovery tank. if bad replace with one that wont collapse while under vacuum.


Bruce

 

No, the temperature is always done by cables, but their ends are known to slip in the clips, and the door is known to break away from the control shaft.

Virtually ever radiator drain on every vehicle is opposite the lower hose, facing the back. You don't have to remove the fan shroud, but it might make it easier to get your hand on the valve. Personally, I don't mess with it. Just warm up the engine (not HOT - just until the t'stat opens) with the cap off, disconnect the TOP hose, & put a running water hose into the radiator and let the upper hose dump old stuff out. When it runs reasonably clear, remove the water hose & let the engine run a couple seconds to pump out as much as it can. Turn it off, reconnect the hose, put in a gallon of REGULAR (not long-life) coolant concentrate (not ready-mix) and top it off with water. Do that every other year & you'll never have problems.

You can use some flush additive if you want, but I've never found any that I could tell helped anything.

All but the oil pressure, and it can be made to work VERY cheaply & easily. But they're just GAUGES - not METERS. They're only there to show CHANGES, and that's all you really need.