Too much oil in AC system symptoms and troubleshooting tips

As an Amazon affiliate, we earn a commision from qualifying purchases.

We reveal the most common too much oil in AC system symptoms in this short article..

As you might be aware, having the proper amount of oil in your air conditioning system is essential for your unit to achieve optimal cooling.

Not only will the right amount of oil keep the various compressor parts adequately lubricated but it also helps protect the rubber seals thus reducing refrigerant leakage to name but a few of its vital roles.

Now, to be safe, it’s important to keep an eye on the system for an oil overcharge- you may have added to much oil by mistake or you’re working on a system that you’ve not yet learned fully.

This article reveals the telltale signs that you have too much oil in ac systems.

Too much oil in ac system symptoms

Watch out for the following signs if fear that your AC system is flooded with oil.


1.     Oil pooling in various places

If you’ve added more oil than recommended to the system, it could pool in a couple of places in the system besides coating condenser coils and the evaporator’s inner walls.

The net effect is a diminished ability to absorb/dissipate heat and you’ll experience a downturn in the system’s overall cooling performance.

This is one of the most straightforward symptoms- simply observe all around the system and see if oil has collected in strange places.


2.     High AC pressure

Though the elevated AC pressure (meaning hindered or zero airflow via the condenser) may be caused by a broken condenser fan motor or a clogged condenser fan, you cannot rule out the possibility of an oil (or refrigerant ) glut being the source of the issue.

Start by testing the condenser fan motor and clearing any debris near your unit’s condenser fan before making any conclusions.


3.     Inefficient Cooling

The most glaring sign of an overfilled AC system is poor cooling because an internal coating forms resulting in reduced heat transfer.

For instance, you might notice that it’s taking way too long to cool things or your windows stop defogging properly.

We are, obviously, assuming that everything else is working fine- the condenser fan(s), there’s  enough refrigerant, your system has no trapped air, etc.

Here is the thing: oil saturation within the system need to be corrected before it’s too late.

And the good thing is that you simply need to deal with the surplus lubricant to restore its optimal performance.

Below is a good procedure to follow:

Removing excess oil from ac system- how to remove oil from ac systems

It’s necessary to drain your AC system if it’s saturated with oil as soon as you can.

Unfortunately, there’s no proper method of just emptying the additional oil (to leave the accurate amount in there) and you’ll need to start from scratch to correct your mistake.

Follow these steps:

Step 1: Disassemble and flush the system

An evacuation tends to only remove air and moisture.

As such, it’s recommended that you disassemble the system then flush the permitted system components to remove the oil (you can use a quality flush chemical combined with compressed air to flush the parts).

Step 2: Drain the compressor

From there, drain the compressor.

This can do the trick: simply put it upside down perhaps on a bench (place a rag underneath it) for a few hours or even overnight.

Tip: For legal and environmental reasons, be sure to recover the refrigerant during the process.

Step 3: Reassemble the pieces

Join the pieces back together- don’t forget to replace those requiring replacement- in the appropriate order.

Step 3: Add the recommended amount of oil

Now add the right amount of oil into the system.

Tip: To avoid future issues in the AC components, you should always use the lubricant that properly mixes up with your particular system’s refrigerant.

Step 4: Recharge the system

Lastly, recharge the system and see how it behaves after this.


How much oil should you add in compressor?

You can rely on several different ways to determine how much oil requires to be added into the AC compressor:

  • The tag on the AC compressor

This should be your first stop. It clearly indicates the precise amount of oil you’ll need to add to your system in most cases.

  • Manufacturer’s website

If you were not lucky with the compressor tag method, look for the manufacturer’s website online and search for your model’s reference guide.

You can also tour the blog section to see if you’ll get some ideas.

  • Manual measurement

Here you measure the volume of lubricant that comes out when draining the compressor (step 2 above).

You note this down.

With that, there’ll be no guesswork moving forward- you will just be required to add the exact amount you had drained out!

Tip: Bear in mind that new compressors nowadays come pre-filled with oil and you must drain the necessary amount from the compressor before installation.

Too much oil in ac system symptoms – frequently asked questions

Can too much oil cause high AC pressure?

Yes. As I had said before, excessive oil in the coolant system can cause higher AC pressure readings.

Of course, there are other potential culprits including a faulty condenser fan motor and debris close to the fan (blocking air flow).

For this reason, you should check these before concluding that your system is oil-logged.

Does evacuating an AC system remove the oil?

As already mentioned, an evacuation will only succeed in removing air and moisture but not oil.

You should start from scratch if you really want to clear the oil and refill to the proper level.

Final thoughts

An oil overcharge can trigger countless problems in your AC system including inadequate cooling and premature compressor failure.

Keep an eye on the above too much oil in AC system symptoms to save your unit and keep cool.

Word of Caution:

Always consult your manufacturer to confirm the amount and type of oil to use for that specific refrigerant before servicing your entire system.



AC power consumption vs temperature – what to know

York air conditioner problems and troubleshooting guide


3 thoughts on “Too much oil in AC system symptoms and troubleshooting tips”

  1. I replaced compressor, condenser, front and rear expansion valves, as the recommended amount of refrigerant oil for the 2011 GMC Acadia is 6.5 oz, I assumed that I had to add about 4.5 oz plus 2.0 oz that the compressor had, without keeping in mind the oil remaining in the lines and the two evaporators, symptoms were that the amount of refrigerant was only 1/3 of its capacity (12oz), and the pressure on both HS & LS went up to 35-40 psi on the LS and 200 to 250 on the HS, temperature coming out of the middle ac vents was about 70 F at idle and about 60 F at 2500 RPM, I flushed all lines and evaporators with solvent that supposed to evaporate after blowing air, I did flush condenser only with compressor air at about 120 psi until almost no oil coming out from it, I placed a napkin on the outlet of the condenser to see the oil coming out, replaced everything back together and still the same, not cooling well, also static pressures not equal, LS about 80 psi and the HS about 120 psi, that condenser has the dryer compartment built in, that’s why I did not attempt to use any solvent but I’m afraid that dryer got stuck oil in it plus oil coating all over the inner walls of the condenser, my question is, should I need to replace the condenser even it was brand new? My guess is “yes” but I wanted to confirm it before I do the expense, thanks for your help.

    • Hey Jorge, I feel for you because this is EXACTLY what I’m going through!
      I felt like your question was coming out of my mind almost word for word. Lol

      I added too much ac oil to my 99 Tahoe and am hardly getting any cool air in the front air so now I have to take it all apart and flush to re-oil from scratch and replace rear expansion valve and front orifice tube.

      I just put in a new condenser that can’t be flushed but I don’t want to replace it just yet. How did you end up solving your situation?

    • The most likely place to have excess oil accumulate is in the evaporator and accumulator if included as part of system.

      Liquid refrigerant carries the oil well. Compressor regulates how much oil is fed to compression chamber and out into system. Bottomline, it easier to get oil out into system.

      When refrigerant turns to vapor in evaporator the oil stays as liquid and drops out. From that point on it is vapor mass flow that pushes (blows) the oil back to compressor.

      If a compressor fails for poor compression, it could have gotten oil out to evaporator through liquid at lower ambient condenser temps but once in evaporator there is not enough vapor mass flow to get it back to compressor. Excessive amount of oil accumulates in evaporator and/or accumulator.

      Then a new compressor is installed with a full load of sump oil and new compressor restores proper mass flow to system. All the oil previously left in evaporator and/or accumulator will now return to compressor possibly resulting in too much oil in compressor.


Leave a Comment