FJ62 coolant overflow reservoir is bone dry after about 3-4 days, no puddles under truck (1 Viewer)

[TheElegantFox]

I have a feeling that my engine is running hot and boiling off the coolant, but my temp gauge is dead so I'm not sure. If I add coolant to the fill line in the overflow tank, it'll drop about an inch after a day of driving. Also the engine blower motor has started running for about 5m after I shut off the truck, not sure if it's running hot or if that's just the N.C summer.

If my overflow tank is regularly empty with no visible signs of a coolant leak, what should I check as the source of the problem?

 

[tmxmotorsports]

My 62 carb fan comes on also after i am done driving i live in Currituck Nc. I would say keep adding and see if it will finally stop may have had air in the system.

 

[TheElegantFox]

Sounds like a good plan to start with. Is the temp gauge failure indicative of a failed temp sender? I did a search and that seems like a place to check, although I’m not sure where to check for it.

P.S I need to make it out to Currituck this summer, I haven’t gotten the wheels on sand yet

 

[g-man]

temp gauge not moving could be a temp gauge failure, a loose wiring connection at the sender or a bad gauge. I don't know anything about a 62 or 3fe but most vehicles have the temp sender on top of the head and prob nearer the firewall. It should have one wire going to it and a shove on female spade terminal. You can ohm test the sender without removing it. Ground your neg lead on your ohm/multi meter and put positive lead on the metal top of the sender. The FSM will show a normal ohm range for your motor at operating temp. If your gauge is always cold but you perhaps have seen it move a little it could be a stuck open thermostat.

 

[OSS]

if the engine keeps on drinking coolant after two weeks of driving it every day, either the head gasket is blown or the head is cracked or there's a leak somewhere. The engine shouldn't drink any coolant when it's all settled down. None
There's a few reason why the temp gauge in the cab doesn't work, but an easy one to check is to make sure the wire is connected to the temperature sender. On the 3FE it's located in the thermostat housing at front of engine.

 

[g-man]

If you have electric blower fan on the radiator it may be designed to continue to run if engine is still hot. I know aftermarket electric fans have temp sensors that go in between the fins of the radiator. And engine temps normally climb when you stop because no air is getting pushed thru the grill and if you have a mechanical fan it too has stopped.

 

[g-man]

Do you have white smoke blowing out the exhaust at start up? You can remove the valve cover and look for coolant puddling on top of the head....indicative of cracks in the cylinder head.

 

[2mbb]

when the engine is cool, take of the radiator cap and fill it up. Then you will know it is "mostly" full.

Check the overflow tube (from the cap to the bottle) for holes. I'm not sure it would cause the symptoms you are seeing, but it is easy to check.

Get a coolant system pressure tester and check for leaks. The liquid is going somewhere--either leaking or burning.

If you can't get your OEM temperature gauge working, get an IR thermometer and check temperature at the radiator inlet and outlet. a proper mix of coolant, at the proper pressure will not boil until the temperature exceeds 250F.

 

[TheElegantFox]

Well, after poking around for the temp sender, I think I may have found a simple leak, it’s just odd that is doesn’t puddle. I'm surprised I missed this in my once over, it was staring me right in the face.

Is this an easy fix like a hose swap?

 

[OSS]

Tighten up the clamp . Or better, replace it since it's pretty rusty. Toyota still sells those hoop clamps and they're dirt cheap and work the best (they don't mangle the hose).

 

[SteveH]

Is this an easy fix like a hose swap?

I chuckle - like any 'hose swap' on an FJ62 is easy?