Whether you own a Subaru Outback, Crosstrek, Ascent, Forester or a Subaru BRZ, driving this car model gives you one of the best on-road experiences, especially under normal circumstances. But, imagine driving this car model, then out of nowhere, the At oil temp Subaru warning light flashes while in the middle of the road?
It’s frustrating, worrying, and annoying, right? If you’ve never experienced this before, then you’re likely to scratch your head wondering what the hell just happened. So, if this yellow dashboard warning light is exactly what you’re seeing, then you don’t have to worry as we’ve got you covered.
So, in today’s guide, we’re going to have a comprehensive discussion on what At oil temp warning light means, what causes it, its symptoms, and how exactly you’re supposed to troubleshoot it.
What is At Oil Temp?
Now, modern vehicles are coming with newer features that provide information about the car’s performance. One of these features is the multiple sensors that are set up in key areas of the car to give you crucial warnings via alerts on the car’s dashboard or instrument panel.
One of these warning lights is the At oil temp, which simply means Automatic Transmission Oil Temperature System. If this is what you’re seeing, then it means your Subaru’s automatic transmission fluid temperature is reaching the upper limit and is getting dangerously hot.
Now, I believe you must be asking a question about what happens if this warning light comes on when driving. Well, the good news is that this problem will not be fatal at first meaning it won’t hinder the performance of your car in any way. In fact, this car problem can give you an allowance of up to 2 weeks or 500 miles of normal driving without facing any problems.
However, once you hit this point, you’re likely to experience legitimate symptoms that will quickly develop from bad to worse. At this point, you must take your Subaru to a professional mechanic to have the problem fixed. Failure to do that means that you might suffer serious engine damage that can lead to costly repairs or worse, replacement.
Why is the Automatic Transmission Fluid Heating Up?
If you’re driving and you suddenly detect the AT oil temp warning light flashing, then the first thing you’ll do is wonder what exactly might be the problem. In this case, you’ll start investigating to know the cause of the problem. In most cases, the AT oil temp warning light turns on when the temperature of the transmission fluid surpasses the recommended 200°F mark.
But, other than this obvious cause, there are other factors that trigger this warning light to signify danger. So, which are some of these common causes?
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1. Low Transmission Fluid
The first and obvious cause of an increase in AT oil temperature is running insufficient oil in the transmission system. You see, the transmission system consists of a set of gears that demand sufficient oil to lubricate them. This makes shifting the gears quite effortless. If the transmission fluid is low, then it means the movement of the gears will suffer causing a build-up of heat hence a temperature rise.
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2. Low Oil Pressure
Sometimes the problem might not be caused by low transmission fluid but rather low oil pressure in the transmission system. Now, several factors can cause low oil pressure such as leaking valves, clogged oil filters, low transmission fluid, and faulty pressure gauge.
When this occurs, the oil will fail to reach crucial engine parts where it’s needed most. This will cause metal parts to grind against each other causing the temperature to rise. In the process, the AT oil temp warning light will get triggered.
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3. Malfunctioning Oil Pressure Sensor
Sometimes you might be dealing with a false problem. In case the oil pressure sensor is faulty, then it might send false data to the car’s ECU causing the AT oil temp warning light to come on. An oil pressure sensor can malfunction due to normal wear and tear.
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4. Using the Wrong Fluid
The last cause of AT oil temp warning light is using a different transmission oil than what is recommended by the Subaru manufacturer. Although different oil will work for your Subaru, it won’t be long before the vehicle begins to malfunction. One of the symptoms you’ll see is AT oil temp warning light turning on unexpectedly.
Some Obvious AT Oil Temp Symptoms
Just as we mentioned earlier, modern Subaru vehicles are fitted with sophisticated technology that turns them into self-diagnosing systems. This allows the car’s owners to identify problems and fix them immediately before they become worse. So, which are these Subaru symptoms you’re likely to see?
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1. Constant Flashing of the Oil Temp Warning Light
The first and obvious symptom of AT oil temp in your Subaru is a constant flashing of the warning light on the instrument panel. In most cases, this warning light is triggered when the ECU detects an abnormal rise in the transmission fluid temperature. So, if this is what you’re seeing, then you should stop the vehicle to allow the engine to cool down before seeking help from a professional mechanic.
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2. Transmission Failure
Another common symptom of an AT oil temperature is the malfunctioning of the transmission system. In most cases, this happens when you fail to correct the AT oil temp issue early enough. By ignoring this warning signal, you end up making the situation worse by causing the entire transmission system to fail due to insufficient lubrication.
How Do You Fix the AT Oil Temp Problem?
At this point, we assume you’re aware of what AT Oil Temp warning light means, its causes, and some of its obvious signs. What you might not know is how to fix the problem. So, that’s what we’ll be discussing in this sector. Now, the good thing about Subaru vehicles is that fixing the AT oil temp problem is easy and pretty much straightforward. Here are some of the steps you might need to follow.
- Step One: Stop the Car Immediately
If you’re driving and the AT oil temp warning signal turns on unexpectedly, you should immediately pull over. This involves finding a safe location to park your Subaru. Next, turn the engine off or allow it to idle for a few minutes. This helps to relieve the heavy burden from the engine by shutting down most of the moving parts. The air flowing beneath the car while it’s off will then take over and cool down the oil.
- Step Two: Inspect AT Fluid Level
Once you rest the engine for several minutes, the AT oil temp warning light should turn off indicating the transmission oil has cooled down. But, what if the signal on the instrument panel doesn’t turn off? Well, in this case, you’ll have no other alternative but to inspect the fluid level.
So, in this step, you’re going to inspect the transmission fluid level to see whether there’s a shortage. Here, you have to turn the engine off completely before checking the fluid level. In case it’s desperately low, you can simply top it off to get it back to the recommended level.
- Step Three: Change the Transmission Oil and the Filter
In case topping up the transmission fluid doesn’t work, then the last option you’ve got is to replace the entire fluid and the filter. So, here, you can decide to DIY or you can opt to take your Subaru to a professional mechanic to replace the transmission fluid for you.
In most cases, most automotive manufacturers such as Subaru recommend their clients to change transmission fluid every 30,000 miles or 2-years. During this time, the fluid must have lost most of its properties making it weak and unable to enhance engine efficiency.
FAQs: Frequently Asked Questions
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Q1. What’s the Average Oil Temperature on a Subaru?
The average oil temperature on a Subaru is anything around 175°F. The temperature can be slightly higher than this, which is also fine. However, if oil temperature surpasses the 200°F threshold, then it means it’s dangerously high and can cause problems to the transmission system.
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Q2. How Long Should You Drive With Insufficient Transmission Oil?
If you’re driving a Subaru, the longest you can drive with low transmission oil is 500 miles or 2-weeks. During this time, the car will feel normal and quite drivable. However, once this period elapses, the car will start to develop serious mechanical problems that can be very costly to repair.
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Q3. Why Does the Transmission Oil Get Hot?
There are several reasons that cause the transmission fluid to get hot. One of them is low transmission oil which leads to low pressure. Once pressure is low, the oil fails to reach crucial moving parts within the engine causing friction and heat buildup.
Other times, the problem can be due to faulty mechanical parts such as the oil pump. If the oil pump is damaged, then it will be unable to pump transmission fluid to crucial parts causing friction and heat buildup.
Final Thoughts
So, are you staring at a yellow warning light indicating AT oil temp? Well, this short insightful guide has offered you information that will really help. Just a recap of what we’ve covered, we’ve explained what AT oil temp means, its causes, symptoms, and how to fix it.
If you’ve read and understood each section, then there’s nothing more to add. However, I would like to mention that transmission systems are very complex. So, if you’re just an ordinary home mechanic or simply a Jack-Of-All-Trades type of mechanic, then it’s wise to leave the transmission system to an expert mechanic or an authorized Subaru dealership.
