Well this aint good...

[rusty ol ranger]

Maybe a stuck thermostat or faulty water pump?

I buy the “lifetime” warranty water pumps at Autozone since it means as long as you own the vehicle. If I even suspect it’s not doing it’s job on even a 4.0 (since they are closely related to the 2.9), or if I’m swapping motors, pump gets warrantied. I’m not playing. Thermostat and water pump are cheap insurance. Also what is the condition of your clutch fan?

T stat i just replaced a couple months ago.

Water pump ive never touched.

I still had good heat, so id assume it was circulating, but that said ive never had a vehicle overheat when it was 5* out...so i dont know if that was a good indicator.

Im not sure. Something obviously went on. I drove it 3 mi to park it at the gas station after it cooled off and the temp gauge stayed right where it always did (O in norm). Even when i let it idle for a bit.

I always freak out and assume the worse. I pulled the dipstick but couldnt see much in the light from my phone. Hoses/belts all intact.

There was snot under the cap but not massive amounts. I dont know if it really got that hot...it did spew a little from the cap when i shut it off and opened hood but while running i dont think it got but maybe a needle tick above the normal band. On any other engine i wouldnt worry. But....it is a 2.9 as much as i hate to say that.

I know youre not supposed to shut off during an overheat but i was afraid it would keep creeping up...so i kinda had a choice to make.

Either way, ill know a bit more later today. Its suppoaed to be like 55 monday so ill probably see what really comes of it then.

 

[85_Ranger4x4]

I kinda question the thermostat, it may have stuck and released after it cooled down.

How does the oil look? Snot on the cap is normal this time of year. Chocolate milkshake oil isn't.

 

[lil_Blue_Ford]

T stat i just replaced a couple months ago.

Water pump ive never touched.

I still had good heat, so id assume it was circulating, but that said ive never had a vehicle overheat when it was 5* out...so i dont know if that was a good indicator.

Im not sure. Something obviously went on. I drove it 3 mi to park it at the gas station after it cooled off and the temp gauge stayed right where it always did (O in norm). Even when i let it idle for a bit.

I always freak out and assume the worse. I pulled the dipstick but couldnt see much in the light from my phone. Hoses/belts all intact.

There was snot under the cap but not massive amounts. I dont know if it really got that hot...it did spew a little from the cap when i shut it off and opened hood but while running i dont think it got but maybe a needle tick above the normal band. On any other engine i wouldnt worry. But....it is a 2.9 as much as i hate to say that.

I know youre not supposed to shut off during an overheat but i was afraid it would keep creeping up...so i kinda had a choice to make.

Either way, ill know a bit more later today. Its suppoaed to be like 55 monday so ill probably see what really comes of it then.

Unfortunately a new T-stat doesn’t mean what it used to. I bought a 180* for my Ranger and it was opening at 165*

An infrared thermometer can really help diagnose stuff.

Can you do a compression test? Maybe you’ll be lucky and a head gasket is starting to go?

 

[19Walt93]

Don't rule out the thermostat just because it's new. The vibration diag manual Ford released in the early Fairmont days would often say to "substitute a known good part" and that "a new part is new, not necessarily good". I replaced the thermostat in my truck early this summer because it was sticking open and the replacement started sticking open before I parked it last month.
Good luck with it.

 

[rusty ol ranger]

Unfortunately a new T-stat doesn’t mean what it used to. I bought a 180* for my Ranger and it was opening at 165*

An infrared thermometer can really help diagnose stuff.

Can you do a compression test? Maybe you’ll be lucky and a head gasket is starting to go?

I can buy a tester yeah. I had one but it wasnt working when i used it on my bronco....it was saying like 3 cylinders had like 200psi or whatever it maxed at.

Yeah on the T stat. It was a 180. Motorad i think...same ones i always buy.

Just strange....i had no warning of anything untill today. Never used coolant, nothing.

Is what it is i guess

 

[Blmpkn]

Id put a 2.3 in it before i did that

Big brain move right there doooooo iiiiiiit!

 

[rusty ol ranger]

Big brain move right there doooooo iiiiiiit!

Nahh lol.

 

[85_Ranger4x4]

I can buy a tester yeah. I had one but it wasnt working when i used it on my bronco....it was saying like 3 cylinders had like 200psi or whatever it maxed at.

Yeah on the T stat. It was a 180. Motorad i think...same ones i always buy.

Just strange....i had no warning of anything untill today. Never used coolant, nothing.

Is what it is i guess

You can test a thermostat in a pot of water on the stove with a candy thermometer to see when it opens.

Sounds like yours may be intermittent though.

 

[rusty ol ranger]

You can test a thermostat in a pot of water on the stove with a candy thermometer to see when it opens.

Sounds like yours may be intermittent though.

Yeah i was gonna test it when i started digging into it.

I might just go ahead and replace it assuming nothing else is screwed

 

[85_Ranger4x4]

Yeah i was gonna test it when i started digging into it.

I might just go ahead and replace it assuming nothing else is screwed

Test the new one...

 

[rusty ol ranger]

Test the new one...

Pry a good idea.

Cant believe part quality has come to that

 

[85_Ranger4x4]

Pry a good idea.

Cant believe part quality has come to that

Not bad insurance, dad has done it forever. If you get a bad one in a system with 2-3 thermostats (like most tractors) it makes things goofy.

 

[SenorNoob]

I couldn't get a good new thermostat locally when I swapped the 4.0 in. I had to order a Motorcraft from Rockauto...

BTW I did test in a pot of water. Had 7 new ones that didn't open at all in boiling (212*+) water.

 

[rusty ol ranger]

I couldn't get a good new thermostat locally when I swapped the 4.0 in. I had to order a Motorcraft from Rockauto...

BTW I did test in a pot of water. Had 7 new ones that didn't open at all in boiling (212*+) water.

Thats bullshit

 

[Jazzer]

+1for using Motorcraft only, and pre testing. If I recall correctly, the hole with the nail in it goes up to help bleeding the air out.