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Discussion Starter · #1 ·
Surpringly, I'm not seeing any lights or codes thrown. My wife asked why her car was getting so loud when in park. I rode with her and discovered the radiator fan would go into high speed mode when the car wasn't moving, sounded like it was trying to take off. I hooked up my monitoring tool and set it to display engine, intake, and ambient temperatures. Engine temps were pretty high.


It's about 25 degrees F out here.


If I set the interior fan to full high and full hot, at highway speeds it would hover at around 230. Turn off the heat and it would climb up to 239 before I turned the heat back on. The air coming out of the vents is HOT - no complaints if you were cold before getting in thecar.


On back roads, if the engine is only at idle speed, the air coming out of the vents suddenly drops to cool and the engine goes up to 235. I can return the vent air to HOT and the engine to 210 by switching to "manual mode shift" and bumping the engine speed back up to 2500.


Got home, used a non-contact thermometer, and registered about 25 degrees on the radiator (I wasn't sure which side it was, so I measured both - and both showed 25 degrees). So it looks like almost no fluid is making it into the radiator.


The vent heat makes me think it's an underperforming water pump - maybe a few blades knocked off. If you're running high RPMs, it has enough force to move some water.


The fact that the radiator was almost ambient makes me think thermostat, though.


Car is well out of warranty (130k miles?), so I'm doing the work myself. Should I just replace both while I'm in there? Could one failure make the other happen? Or is just one item failed and making the other look bad as well? Anyone see this kind of issue and get it fixed?
 

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Thats about the correct temps for the car to run. Make sure you're over-flow tank has fluid in it, and is right at the first line below the filler cap on the side of the tank. If not, add some.
Check it from time to time. As its a known issue in these cars.
Water Pump should still be covered under powertrain. (150K miles on this) (if I remember correctly)
 

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Sounds like the thermostat isn't opening if the radiator is that cold. Possibly with an air bubble in the system.

Expansion tank is filled when the car is cold?

I think I'd start there before tackling the WP. As someone else said, there is an extended warranty coverage on the water pump as well.
 

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Discussion Starter · #5 ·
Yes, expansion tank is full, and there's been no signs of leaking. I'll do the thermostat first, then see if all the symptoms go away. If not, I am still well within the 150k for a water pump. Thanks all!
 

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Discussion Starter · #6 ·
The saga continues.

I took it to the dealer and they said thermostat, $300. I said no thanks and did the thermostat and pump myself, since I had already bought the pump. The old pump looked OK, so instant regret. However, after replacing the thermostat, everything seemed to start working again.

Then we started noticing coolant loss. My first thought - blame my sealant job on the pump. I ordered a siliconized gasket and topped it off. The next day coolant loss was much higher but clearly on the driver's side of the engine (hitting something hot and producing steam). Turns out that the coolant return hose (which I removed to help drain the system) had cracked. The problem was that I removed it by pulling the metal clip on the mixer body, but it was the next connection up (a squeeze-and-release connection) that broke.

Replaced that hose, topped up with coolant, thought everything was good. My wife borrowed my car for a holiday trip (I stayed home to work), so I was driving the car for a few days - maybe half hour drives at most.

This morning she got 5 minutes from home and got an overheat warning, with my OBDII sensor showing 280 for engine temp. I had her turn it off and tow home. She said coolant level is OK. I'm wondering if the system lost more coolant than I thought and either a) needed better radiator burping, and now there's an air bubble somewhere, or b) thermostat/pump ran dry at some point and was damaged by that. I'm guessing if it's the latter, it's the pump, since it probably uses the coolant for self-cooling and maybe lubrication.
 

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Discussion Starter · #7 ·
And the winner is... failed temperature sensor!

I got to the car after it sat 8 hours in below freezing weather, and the OBDII display showed engine temp still at 210 degrees. The engine would turn over but not start. Unplugged the temp sensor and she fired right up, now showing -40 degrees and "No A/C Due to High Engine Temp" warning on the dash.

The whole cooling system has been up and down, so maybe like the hose, it was already close to failing and fiddling with it caused an issue. Or maybe the coolant leaking right above it did it in?
 

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Normal operating temps are 170 to 195. Average of 180 - 188. On my 17 cruze so far with less then 3000 miles.

The post below yours saying your running normal is WRONG. 239 degrees is bad news for the engine.

You caught your car at 280 degrees should have been the first sign something isn't right right there. Ain't nobody running that hot. Motors will fry long before they get that hot.
 

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Thats about the correct temps for the car to run. Make sure you're over-flow tank has fluid in it, and is right at the first line below the filler cap on the side of the tank. If not, add some.
Check it from time to time. As its a known issue in these cars.
Water Pump should still be covered under powertrain. (150K miles on this) (if I remember correctly)
The correct temps are 180 - 190 with the fan kicking on somewhere around the 210 mark. If the car were to sit and idle. I haven't tested my car to see where the fan kicks on at.
 

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Normal operating temps are 170 to 195. Average of 180 - 188. On my 17 cruze so far with less then 3000 miles.

The post below yours saying your running normal is WRONG. 239 degrees is bad news for the engine.

You caught your car at 280 degrees should have been the first sign something isn't right right there. Ain't nobody running that hot. Motors will fry long before they get that hot.
Normal operating temps for a Gen 1 are 190-230F. Fan runs at 230.

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230 seems pretty hot.
Thermostat is fully open by 219-225, but fan holds off til 230 (1.4T anyway; 1.8 may be different).

The Gen 1 has an electronically controlled thermostat that melts a wax ring with a heater when it wants to change that temperature to a lower point (e.g. under a load or in hot summer temps). Otherwise it tries to run as hot as possible for efficiency reasons (which also leads to high cooling system pressures which leads to coolant vapor smells often in the Gen 1).

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