Hey, does anyone have experience with their coolant disappearing ? I have a 2008 4.0 ranger.

I changed the oil and noticed a drip which caused me to look at the coolant - the tank was empty.

filled the tank and took it to the dealer to get it fixed/ find the leak. I was told it was the water pump. So they swapped out the water pump for a new one. That was yesterday.

I noticed a small wet spot on the concrete today after I drove to work and the truck had been sitting all day.

I never noticed a smell, burning, fumes and the temp. gauge always stays below half. Checked the radiator and the tank again, tank was empty - rad also looked to be pretty empty. Any thoughts on where the coolant could be going ? Where to look? I can’t see any evidence of coolant on the engine

Thanks for the suggestions

 

Welcome to the forum

Dealer should have another look FOR FREE because their diagnoses was not complete, they should have pressure tested the engine/cooling system once it was refilled, takes maybe 10min including a 5 min smoke break, lol

But a known leak point on the 4.0l SOHC engines was the thermostat housing, it would crack, coolant leaks out on the TOP of the engine and evaporates before dripping to the ground in most cases

Best way to find a cooling system leak is to rent a cooling system pressure tester, its just a rad cap with a hand pump and a pressure gauge attached

COLD engine
Install the tester on rad, make sure rad is full of coolant
Pump pressure up to 20psi
If there is a leak you will see pressure dropping
Start looking for the leak, engine is cold so you can feel around , and coolant WILL drip to the ground eventually, lol


If pressure holds then NO LEAK in the engine system
So overflow hose or overflow tank is leaking

 

Hey Ron,

thanks for the quick reply. I thought I would update the forum with the response I got from the dealer.

i took the truck back and mentioned the issues in the first post. They took a look at it and found an air bubble in the coolant line. So they burped the system, added more coolant and pressurized the system. Told me there were no leaks despite what I saw under the truck yesterday.

im going to continue to monitor the bottom of the truck to see if I notice any drips. My other question is what would an air bubble do to the engine/ parts of it went unnoticed ??

thanks hopefully this helps others too.

 

Generally speaking when you refill a cooling system you unhook one of the heater hoses at the firewall to let the air out of the engine while refilling
The thermostat, being cold and closed, prevents air from coming out very fast
So if they didn't do that then air could have been trapped in the engine side of cooling system
After start up the water pump starts to circulate the coolant and any air will move to the higher points of the engine side of the system, which are the heater hoses
The air can cause an "air dam", the water pump circulation pressure simply can't push it out of the heater hoses if there is too much air

You would have no HEATER if this was the case, engine wouldn't overheat

Driving at speed, faster water pump RPMs, will often push the air dam out and that air will travel to upper rad hose, thermostat now open, and to top of rad where it would stay
As engine reaches operating temp the rad cap would open and the air at the top of rad would be pushed out and bubble up in overflow tank, this is why the overflow hose comes in at the bottom of the overflow tank, so any air would bubble up and be gone from the system

After shut down of the engine, if cools off and rad cap opens again and sucks back coolant from the overflow tank to refill rad with coolant, not air

So overflow tank level may have gone down because of that, but most of the air in the engine side should have been purged...................so grain of salt on their diagnoses, it is possible there was ALOT of air left in the system, but a few drive cycles, heat up/cool down, should have purged it all

But no leaks on a pressure test is a GOOD THING