Still can't find the overheating issue
 

Greetings,

I posted before about my 2001 Camry: https://www.camryforums.com/forum/ge...e-input-39917/

This is what I have done thus far:

Replaced Tstat.
Flushed radiator both on and off vehicle. Used a vinegar flush when it was off. I get good flow throught the radiator.

Lower hose says fairly cool after a long drive. I have noticed that, whereas before the cooling fans would only cycle on and off when the AC was on, they will now cycle on and off with the AC off, as long as the blower is on.

When I look down the throat of the radiator as the car heats up, I don't really see any movement of coolant. Usually, what will happen is that if I remove the cap and start the car, as the car warms up some of the coolant will back out the filler, maybe as much as 3 or 4 ounces over about ten minutes. It will then stop. The car seems to get a bit too hot under harder driving conditions; uphills, highway, etc. unless I keep the heater blowing.

Could it be the water pump is just not up to snuff?

Only other thing I have noticed is that when the fans cycle on, there is a little bit of a high-pitched screeching or whining, not loud, but noticeable. Camry has 160,000 miles on it. Original radiator and water pump.

Regards, Brenden.

Whining from where?

It is rare for the impeller to fail but happens. The pump impeller blades corrode a point there is no blade left to move the coolant. Or the impeller comes loose from the drive shaft.

Have you changed the radiator cap.

What is good water flow in GPM? Any estimate?

Hi Joey,

I will try to answer as best I can. The cap is the original as far as I can tell, since I have never changed it and bought it from a rental agency at 20,000 miles.

Whining from where? Beats me. :) It just is a noticeable slight whine/screeching sound. It's not like the old loose fan/alternator belt whine, more quiet than that, maybe more like a slight "whistling" sound, but something that I have noticed over the past couple years. Starts when the fan blades cycle on, then stops when the fans stop. Nothing appears to be obstructing the fans and they spin freely.

As far as flow. I can't say. Like I say, when I start the car cold with the cap off, the coolant backs out of the filler opening a little at a time as it gets to operating temperature, then it stops. If I blot the radiator coolant out with a rag so I can get the level a little lower, so that I can view the coolant over the little "slats" (whatever those things are at the top of the radiator) I can't say as I see any real movement. It must drain and circulate at some point, because when I changed the Tstat and then filled the radiator with coolant I took it for a spin and after a couple minutes the temp shot up, so I pulled over and stopped the car. After it was cooled down, I opened the cap and saw that the coolant was way down so I topped it up with a half gallon, capped it, and everything was back to "normal".

Is there any way to tell if the pump is doing it's job?

Regards, Brenden.

UPDATE:

So, two things I noted. One, the plastic shield on the underside of the of the car is cracked/gone. I have a vague memory of that thing dangling there for some time and I finally got tired of hearing it drag on low driveways so I yanked it off. However, it seems this cooling issue may have pre-dated that. Does this have any effect on cooling?

Second, the other day when I got home and backed the car in our parking space, I had the fan turned off; the car was starting to go up above the 3:00 mark, and, when I shut the car off I quickly popped the hood, and I think that I may have seen a little puff of vapor at the upper end of the radiator, and a slight smell of coolant. Again, I can't be sure. Now, if there was say even the slightest of a pinhole in the radiator, would this be an answer?

Regards, Brenden.

The plastic cover keeps water and debris off the engine and belts. Provides improvement in aerodynamics, might aid in airflow through the radiator plus?

Doubt it's absence is causing the overheating.

Check the upper radiator tank for hairline cracks the can leak. The upper tank can crack resulting in very slight leaks at first but can be much larger over time.

If the lower plastic shield were in place coolant might be collecting there from any leak.

There were a few threads in late summer and Fall about overheating. On my '94 it was a case of a bad water pump. Weak, but not totally gone. When removed by my mechanic, the plastic impeller blades were worn down to about 1/4.

When a new one was installed, looking down through the filler block (mine has only one radiator cap. some models have two) with the thermostat opened (operating temperature) , the water swirled around noticeably at idle. With the engine revved up, it was clearly agitated by the pump action.

The mysteries continued. A month later (after new pump, thermo, hoses, belts, and radiator cap) the radiator seams gave way and were venting steam on the inside, front of the hood. That was an easy fix.

To check the pump, with the motor warm (and radiator cap off), look for swirling water. Be careful working with a hot engine and the cap off.

Hey Joey and Bravo,

Yeah, I look in the radiator and I never see swirling. I remember seeing swirling on my old 73 Dodge Dart (my first car) back in the day. Im starting to wonder if the pump isn't going.

Regards, Brenden.

PS. Anyway to tell for sure besides pulling it? Can I see the blades anywhere without yanking the pump, feel them, etc?

Might be possible? to see the impeller if you remove the T-state housing then insert a small mirror into the hole and have a strong source of light.


The photos below will provide the location of the impeller in reference to the housing.

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