my car tends to overheat when the weather is hot, so i figured i would check airflow and whatnot. So far, I've done several things, and nothing is working to fix this issue.

1) Radiator: After cleaning out my radiator and ridding of any potential airflow obstructions, the radiator is in good condition... not perfect, but well functioning. There are no cold spots, the fins are clean, and the fluid leaving the radiator is obviously cooler than the fluid entering.

2) Fan: It's a clutch fan. It spins. It works...

3) I flushed the coolant, and replaced it with new 50/50 mix. Coolant is fresh.

4) Time to pull out the big guns. Thermostat: I removed the thermostat, and still the car overheats and warms up normally. What?!

5) I performed a "gauge check", where I tested the temp gauge by itself to make sure i was getting a positive reading. It works.

I think the last step is replacing the water pump, but I want to make sure that the water pump is at fault here. Is there any way to confirm that the water pump is the culprit? What tests can I do?


I've looked all over the place for help, and it seems that people with similar issues did not have to deal with their cooling system this much to fix the problem. Any help is appreciated, thanks a lot!

Josh

 

Water pumps have a little "****" hole. should be behind the pulley.
If it leaks then it is probably time to replace it.

What year and model is the car?
Some have a real coolant gauge, newer ones have idiot gauges.

could be a bad coolant temp board???

Be nice to have a aftermarket temp gauge to know some real numbers....

Wait for the experts to get on.

 

Borrow an infrared themomoeter and confirm you are actually overheating.
Check water pump drive belt.
How did you clean radiator, just an external clean? If so, scale builds up in radiators and can be removed with proprietary cleaning products.
How did you confirm engine fan is working? Get engine to temperature, shut down engine and try to turn fan. There should be considerable resistance in teh fan clutch, I mean hard to turn.
A clutch fan that "spins" means nothing except it's disengaged when you spun it. It can freewheel and be spinning when the engine is turning over but not be flowing near enough air.
A properly working fan of any sort should draw a piece of paper hard against the front face of the radiator.
The water pump won;t be a issue unless the impeller has somehow corroded away or is loose on teh shaft, which I have never seen.

Regards, Andrew.

 

Did you
A.Determine the thermostat is the correct thermostat?
B. test the thermostat in a pan of water heated to the correct temp stamped on the thermostat?
C. throw it away and get a new one anyway?
D. Install a new thermostat?
E. Install new hoses top and bottom to rule out that the hoses are collapsing and blocking flow?
F. Install clear tubing instead of hoses to watch the flow?
G. Boroscope the radiator to check for corrosion?


4) Time to pull out the big guns. Thermostat: I removed the thermostat, and still the car overheats and warms up normally. What?!
The thermostat is there to keep water in the block until it reaches the correct temperature allowing the water in the radiator time to cool to the correct temperature before it returns to the block and start the process over again.
Have you tried turning on the heater to the full hot position with fan on high to see how it effects the temp? if it cools then guage is reading correctly. just when you think youve tried most things there are others that you can try. just dont let that engine overheat!

 

What year is the car? How do you know it's overheating?

 

I have a thermo gun, so i got actual numbers. I measured the temperature for the hose going into the radiator and the hose leaving the radiator. When the car is running at a normal temperature, the inlet hose measures anywhere from 145 F to 170 F, and leaving the radiator is usually 10 to 15 F below that. I ran the thermo gun along the radiator to check for cold spots, but based on the readings, the radiator is functioning perfectly (no cold spots). About 6 months ago, I used a fiber-optic lens to look inside the radiator and it was absolutely free of electrolosis... which is good!

I went back and checked the fan for resistance. I can spin the fan with almost no resistance.... is this the issue? Now that I've been reading about clutch fans, I'm starting to wonder if this is the source of the problem.

 

If you fan is bad your engine should be cooling fine at a highway cruise. The fan is really for when the radiator isn't having air forced through it. Driving your car on a highway I think will put a lot more air through the radiator than the fan. If it's not cooling fine at highway speeds, then I would say that the fan isn't an issue.

 

Your car is not overheating based on teh numbers you reported.
However, you have to make sure you are testing teh clutch fan at it's operating temperature. You should hear it "roar" as teh clutch engages when idling and teh engine gets up to temperature.
You want to get the coolant quite hot, place some cardboard in front of teh radiator and carefully monitor temps. Let teh radiator top tank get to about 200f, the fan should have kicked in by then. So if you don't hear teh fan kicn in at that temp, shut the engine down and give teh fan a good spin. It should have definite strong resistance.
But as I said, based on your numbers, your car is actually running right about where it should.

Regards, Andrew.