I'm suffering from my engine overheating. When the car runs without AC, the heat gauge is slightly above the middle. But when the engine is idling, it goes to three quarters to the top. When the AC is on and I'm driving slowly, the engine overheats so bad the AC stops cooling properly and the only way to bring it back down is by turning off the AC.
I looked at the engine radiator, and found that it is quite worn out, and has so many repair scars around it, and a small coolant leakage. So I assumed the problem is from the radiator and completely replaced it with a brand new one. I thought that the problem will be gone for good, but to my disappointment, the problem was still there, exactly the same way it was before, not even the slightest improvement.
I made sure there is no leakage in the engine coolant, and the engine fan is working well. The only thing I can think of is that the AC radiator, which is directly in front of the engine radiator, is too dirty that it is blocking the air flow into the engine radiator. Any input in that regard would be highly appreciated. Is my diagnosis valid? What else can I check?
I know most of you will suggest to completely remove the AC system, but that is really not an option in our region, where the temperatures reach 50 degrees and beyond for about four months of the year.
Look into the radiator throat with the engine running. Does the fluid move? Does the fluid seem to disappear (get lower) without any visible leaks? If so, look under the rear of the intake manifold and see if you have developed any pinhole leaks in the casting. It is common.
Looking at the fluid, can you see any drops of oil floating? Chacking you oil, is tere any moisture/water on the stick? Either of these signs could indicate a bad head gasket or worse.
Also look at the back of the water pump and see if you have any leaking where the tube plugs in. That is an o-ring that can wear out.
Check your thermostat and make sure it isn't corroded shut.
Since you have already replaced the rad, so unless the connections or the drain is leaking, then you are ok there.
Look into the radiator throat with the engine running. Does the fluid move? Does the fluid seem to disappear (get lower) without any visible leaks? If so, look under the rear of the intake manifold and see if you have developed any pinhole leaks in the casting. It is common.
Looking at the fluid, can you see any drops of oil floating? Chacking you oil, is tere any moisture/water on the stick? Either of these signs could indicate a bad head gasket or worse.
Also look at the back of the water pump and see if you have any leaking where the tube plugs in. That is an o-ring that can wear out.
Check your thermostat and make sure it isn't corroded shut.
Since you have already replaced the rad, so unless the connections or the drain is leaking, then you are ok there.
is that enough to get started?
Ok, is my point valid, that the AC radiator could be clogged up and blocking the air flow?
I need some help with the following, as I'm not an expert in engines:
Where is the waterpump?
Where is the thermostat?
Where do I look for oil drops in the coolant? From the throat or the coolant reservoir?
Ok, is my point valid, that the AC radiator could be clogged up and blocking the air flow?
I need some help with the following, as I'm not an expert in engines:
Where is the waterpump?
Where is the thermostat?
Where do I look for oil drops in the coolant? From the throat or the coolant reservoir?
Well, although the AC cooler may block alot of flow, it usually isn't to blame for that much overheating. The vehicle should not get that hot sitting still for instance. You should be able to run the engine with the AC and headlights on while sitting in the driveway without overheating (no forced airflow). It gets to 110-115 Fahrenheit during the summer here, so we have to watch out for overheating as well.
When you lean over the rad and look down at the fan belts, the water pump is what the fan is bolted to. There is also a small hole in the pump face below the pulley. This is in case the seal blows and then you have a visual indication that you need to replace the pump (you will see water leaking out there).
When you follow the upper rad hose back to the engine, the water tube that it is attached to has the thermostat directly beneath it. Removing those two bolts (that hold on that tube) will allow you to remove the tube and see the thermostat.
Look for oil droplets in the throat of the rad. Use a flashlight if you need to. If the fluid is clear/green then you are probably fine. If you see spots then there may be a problem.
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1.3 Engine Overheating
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