1984 22R carburated engine. Engine has been overheating. I replaced thermostat(it was in pieces) and also the temp sender. And flushed out cooling system, replaced coolant. Now when I drive the temp gauge goes all the way to 90%-100%, but the engine generally doesn't seem to be overheating. The upper hose to radiator is hot, lower hose much less so. No sign of boiling water. Engine does not creak when cooling down(like it would if it was really hot), there is no blast of hot air when I open the hood. Looking in the radiator with engine running, no sign of circulation.

I removed the thermostat housing and thermostat and turned the engine over with a remote starter. There is no sign of water pressure, the water/coolant in the thermostat housing
did not gush up, didn't even move. Would this be an absolute sign that the water pump is bad...this water pump was new two years ago, before I bought the car. Any other reasons there would be no water/coolant flow out of the thermostat housing? Radiator and hoses were also replaced two years ago.

John

Were all the thermostat pieces accounted for?

I have the frame, the spring, the plunger, and the top piece
(shaped like a teepee). The top piece was loose and a bit on the side, the spring and plunger were in the frame. There might have been something else but I'm not sure since I haven't looked at thermostats that closely before this.

The common failure mode for water pumps are:
1- The seals leak
2- The bearings go out

I've never seen one that just stopped pumping without one of those problems as a cause. Check your fan clutch. If you can spin the fan more than one revolution, chances are it's the problem.

Dave

I was once told my lower radiator hose may be collapsing on suction. Since then I got the metal pipe and two lower hoses.

Water pump doesn't leak, no bearing noise (it's only 2 years old), and I can't spin the fan more than 1/4 turn. And none of these would affect coolant circulation anyways. I think that's the problem, at least that's what I'm trying to figure out.

I have had/seen this exact same problem. the engine seems to be overheating on your gauge correct? I have found faulty gauges to be the problem in the 80's models at least three or four times.

I am guessing that the starter does not provide enough spin on the water pump to force the water through the engine. I bet if you ran the engine it would show you that the water pump is fine.

the first time I encountered this overheating problem I changed everything, had the radiator cleaned, and it all came back to the gauge. frustrating to say the least. I realized it was the gauge when I used a meat thermometer of all things on the block and in the water. after changing the gauge it proved my theory correct.

just a hunch this may be your problem

zacaroo...I like your theory, but did your gauge always read high or just go bad one day? Mine was reading perfect (always a little under half) then when this overheating problem started (possibly caused by broken thermostat), it was reading correctly showing the overheating. Then I found the broken thermostat and removed all of it except the frame. Next time I drove the gauge was reading very low, less than 1/4 gauge when warmed up, 1/2 gauge when overheating and coolant boiling a bit. I replaced the thermostat and temp sender and next time I ran the car the gauge went up to 7/8th after a couple minutes and pretty much stays up there(and higher) when I drive...but with no real overt signs of the engine overheating.

I'm curious how you measured the block temperature with the meat thermometer...did you just push it against the metal block and hold it until you got a reading?

sounds like you are doing just what I did, I can't remember the exact chain of events. but to answer your question about the meat thermometer; after i had changed everything it became a hunch to me that the gauge was shot, so i took the meat therm. that i have always kept in my vent blower (another story) and i placed it at several points on the engine, then i put it in the radiator wile it was running and while it was reading damb near in the red and it never got over 180 on the meat therm. and that is what the new thermostat was set for. so then i just got a new aftermarket temp gauge, that has its own sending unit and it also checked out right at 180.

hope for your sake this is your problem too. have you changed your water pump? i think you said you did 2 years ago, not that it should matter. I have had a pump from napa go out (bearings) in less than a year, that one totaly messed up my old 22re on my 4runner. I don't know of a story of a water that just stopped working, usually they leak or fall apart and make a mess. autozone or someplace like it sell easy to install aftermarked gauges that you could pop in your engine and see if this is your problem, you don't even need to mount it to check.

good luck

Does the heater work? If so, then you have coolant circulation. If not, well......

Since you lost some therm parts maybe inside, could a piece of it get caught in the impeller and cause damage that wouldn't cause a leak in the pump? (I'm asking someone who might know). Like Like break off the blades or spin the impeller on the shaft?