Hi all,

I have a 2004 Ford Ranger 3.0L, 4WD, automatic transmission. My truck has been slowly losing coolant. Since filling up the reservoir near the top (about a few weeks ago), it's dropped about a couple of inches to just above the middle of the reservoir. I can't see any leaks (perhaps I'm not checking thoroughly enough), and the truck has never overheated while I've owned it (bought it in March). The exhaust only seems to shoot out some light, white smoke when I turn on the truck in the morning, but I'm pretty sure that's just condensation. I haven't noticed any white smoke while driving. The temperature gauge also stays in the middle when I drive. I should note that it only seems the coolant reservoir is losing coolant, because the coolant in the radiator has remained up near the top the last few weeks when I've removed the radiator cap to check.

This morning, I removed the radiator cap and turned on the truck to see if there were any bubbles surfacing in the coolant, but I didn't see any. The coolant did, however, begin to overflow and spill out of the radiator until I turned off the truck. I attached a video of that. Is that normal? Anybody know how else might I be able to diagnose the truck to figure out why it's losing coolant?

Any help is appreciated. Thanks all.

Leo

 

If you are filling the reservoir to the top, that is your problem, reservoir should only be filled to about the halfway mark.

When the coolant gets warm in the engine/radiator it expands and the radiator cap allows the excess coolant to flow to the reservoir.

When the engine cools down the radiator cap allows the coolant to flow back into the radiator.

So if you are filling the reservoir to the top, the only place for the expanded coolant to go is out the reservoir cap.

 

Hello,
Thanks for pointing that out. I should mention that I actually had the coolant in the reservoir filled about halfway up until a few weeks ago, and it was still losing coolant. When it nearly dropped to the bottom of the reservoir, that's when I filled up near the top. Also, nothing leaks out of from the top of the radiator when the radiator cap is sealed back on even with the higher amount of coolant in the reservoir, so I'm fairly certain it's not leaking from the radiator cap if I'm understanding that right. Do you know if there's any other areas not normally visible where coolant could be slowly leaking out from?

I'm concerned that it could be an internal leak from a damaged head gasket, so I'm going to do get a combustion test kit and see what happens.