Coolant Question

[du510]

To start off - I know very little about cooling systems, etc.

Ive got a '94 4.0L (OHV) with appx 155k on it. Problem is - its been losing coolant. The reservoir wont go completely dry, but it will come close...

So yesterday I was tinkering with the truck in general and noticed the reservoir is near empty. Also, there was some shit inside. I took a photo, its down below.

I refilled it and let it sit for a good couple hours - no puddles. I hadn't run it in a few weeks, so I let it idle for about 45 minutes. No leaks.

Any idea where this coolant is going?? And what is this crap inside the reservoir? Thanks fellas.

 

[Broncodude]

how much fluid are you loosing, are you topping off your radiator and your overflow tank?

 

[du510]

how much fluid are you loosing, are you topping off your radiator and your overflow tank?

Id estimate my loss to be about 80% the capacity of the reservoir... and nope, I am not touching the radiator itself.

 

[Broncodude]

I'm not sure where your leak is but if your radiator is low it will suck the reservoir dry. If you fill your radiator(when cool), then put some in your reservoir you'll get a better idea on how much your loosing. Find someone with a pressure tester to run a test on it.

 

[Kona]

Just for kicks don't top the reservoir up for a couple of days and then check your radiator (when it is dead cold and still be careful opening the cap ) and see if the rad is low. It is really common in Ford trucks (not cars) to go low in the expansion tank but not the rad. No , I have no idea why.

 

[woodyedmiston]

Leaks

Twice I have experienced the plastic tank on one of my Rangers getting a longitudinal crack in the bottom of the tank. It leaks very slowly.

The crud you see in the bottom of that tank looks like rust - how much coolant are you running in your mixture. It needs to be at least half coolant, half water just to keep things lubed. Colder climate more Prestone . . .

If you are rusting inside your engine one of the first things to start leaking will be the freeze plugs. They leak slowly at first and usually don't leave a puddle. There are three on each side of the block, and one in the back of each head.