Overheating. Failed water pump?

[utahman11]

I was idling outside waiting on my wife, and looked at the temperature gauge which was on the redline. Turned off the vehicle and looked in the reservoir. It was low but still had maybe 1/2" in the bottom. Felt the radiator and it wasn't really hot, just slightly warm, so I figured I was safe to open it up and see the level in the radiator... Well that was stupid and a geyser erupted and spit coolant everywhere, the stuff on the top that sprayed my hand, etc, wasn't hot, but it was steaming after a while, so I assume some of it was hot. I poured enough coolant back in to get it full but didn't really do a good job purging the air. I cranked up the heat and was able to drive it to a friend's shop, turning off the motor and coasting when it got close to the redline. I assume the last time the WP was done was with the timing belt ~130K miles ago according to the sticker. (I've been putting it off because it's a N/I motor and I'm tight on money).

So my questions are:

-What are the likely issues causing the overheating?
-Did I screw up the motor driving 30 miles at high temp near the redline? (or possibly for miles before I noticed it high at idle?)

 

[nissanh]

Probably there was a coolant leak and it emptied the coolant to a point it cannot cool the engine any more.

One should not pour cold coolant into an engine that just got overheated. Rapid cooling can cause different metals to cool at different rates and may lock up certain moving parts for example piston to cylinder wall.

If the water pump is non oem, then it could have failed otherwise no. How old is the radiator? If it is 10-14 years old, I am sure it is clogged up.

Engine may or may not be usable because you drove 30 miles with needle at red zone.

Do you find coolant in the engine oil? IS engine oil milky? if not, top up coolant (ONLY WHEN ENGINE IS COLD and NOT EVEN WHEN WARM to touch) and start the engine and see any bubbles coming out of the radiator while the cap is off (WEAR GOGGLES). Any continuous air bubbles flowing out of the radiator indicates a blown head gasket.

You can see the operation of water pump if you allow the engine to warm up to working temperature without the radiator cap on. Again, START when the engine is COLD and remove the radiator cap, wear goggles and allow the engine to warm up. once the thermostat opens, you can see coolant is flowing from driver side to pass side through the radiator.

 

[jgue467]

What makes you think the water pump it not working? Do you see it leaking when you shut the engine off? (that's usually when a failed WP leaks but can do it all the time as it gets worse).

Unless you see it leaking, I'd keep looking for another leak. Water pumps don't just stop pumping, they leak when they stop pumping.

Luck and enjoy the Runner! :cowboy:

 

[Bad Luck]

Likely issues would be stuck thermostat (usually will through a CEL for p0128 but not always), bad water pump (usually will start leaking through the weep hole when it goes bad), or blown head gasket. I wouldn't think you have a leak due to the amount of pressure the cooling system was holding when you opened the radiator cap but it's still worth pressure testing. You can check thermostat operation by feeling the upper radiator hose. If it gets very hot quickly then it's likely a stuck open thermostat, but if it takes about 5-10 minutes to get warm then the thermostat is opening. I'd suggest buying a lisle spill free funnel to help purge the cooling system.

I'd do a compression test and cylinder leak down test to see if you blew a head gasket or possibly cracked a head by operating at high temps for that far. You may have gotten lucky, but most folks that overheat to the point of the temp gauge on the dash being in the red have cracked/warped the heads or blown a head gasket.

 

[gamefreakgc]

Cold coolant in the radiator normally means a blockage of sorts. That coolant should have burnt your hand since the top of the radiator is where the hot coolant comes into the radiator and then exits into the engine at the bottom.

Try warming it up to temperature then feel the upper radiator hose and the lower radiator hose. The top should only be slightly warmer. Notice anything strange or different from that?

 

[JohnMc]

Water pumps don't just stop pumping, they leak when they stop pumping.

Unless it's a BMW with plastic impellre blades, lol.

But yeah, agree with above thoughts.

Failure mode on a water pump is going to be leaking, not a failure to move coolant

Thermostat stuck shut will do what you're seeing. Coolant just gets hot in the motor, not in the radiator. Does the heater put out heat when this is happening? It gets coolant circulation regardless of the thermostat.

Also less likely things like a kinked or blocked hose. A blocked radiator not letting coolant through. Possibly even a bad temp gauge or temp gauge sender, although a fountain of coolant suggests it really was hot inside the block.

 

[SaulG]

First probable cause is thermostat, use whatever you can find but make sure it has a "jiggle valve" or drill one in it. Install it at 6 or 12 o'clock so it balances. If it's availible you may wanna block check it.