Not overheating, but overflowing (1 Viewer)

[4mydogs]

In the time since I got my FJ40 and when I got it running, I flushed the cooling system and replaced the hoses, thermostat and radiator cap. Later I discovered my radiator leaking so I replaced it as well. As I began to drive it on longer trips, 25-30 miles, I noticed that coolant would come out the overflow tube at the radiator cap and I would have to add some back. It didn't have a coolant overflow bottle/return system, so I installed one with a 2.5 quart bottle. It worked how I thought it should the first few short runs, the level in the bottle going up to the hot mark, and then as the system cooled it would return down to around the cold mark. But driving yesterday, around 25 miles and temp around 90, when I arrived at my destination the overflow bottle was full and coolant had come out of its overflow tube. This morning the bottle was still full and the radiator was around a quart low. Also, the coolant in the overflow is brown and smells strange. It's tough to describe but it doesn't smell like any coolant I have ever smelled.

The temp gauge works and it has never read hot.

What's going on/what should I try next? Thanks for any help.

 

[Pighead]

Also, the coolant in the overflow is brown and smells strange. It's tough to describe but it doesn't smell like any coolant I have ever smelled.

Hmmmm...do you have oil in your coolant? Look for water in your oilpan, check your headbolt torque, check cylinder compression. Rule out a bad headgasket...

 

[FishTacos]

Unfortunately, I think Pighead is on the right track. Check your oil. if it is milky, opaque, melted chocolate milkshake color you have coolant mixing with engine oil somewhere (probably head gasket). Check at the dipstick and drain a little from the oil pan drain plug. If it has been parked the coolant may have separated down to the bottom of the sump.

 

[pedwards]

Also make sure you have the correct rad cap with a good seal.
( I think it should be either a 9lb or 13lb cap) this matters. If you only have a 5lb cap, too much coolant will boil out. If your cap isn't creating a perfect seal the the rad will boil.

 

[inkpot]

so is your rig stock, or are you modified with a chevy small block or sometheing else? John

 

[ARCTICMUTT]

What about a bad thermostat?

 

[4mydogs]

Stock F145. 13lb radiator cap is new. I don't see any milky oil on the dipstick. I've been driving it weekly for the past couple months, so the coolant wouldn't be at the bottom of the pan, would it?

I suppose I could swap out the thermostat and see if that makes a difference, but it's new as well.

 

[ARCTICMUTT]

Just put the thermostat in a pot of water on the stove and it should open right around a simmer approx 180 if the water is boiling it is 212 which would indicate a faulty tstat

 

[4mydogs]

Update: Exhaust gasses in the cooling system. Man, the hits just keep on coming.