2017-2023 Jeep Compass Brake Fluid Type and Flush Interval

By Core Brake Parts Tech Team — Circleville, OH warehouse

The 2017-2023 Jeep Compass takes DOT 3 brake fluid: the 2020 and 2023 owner's manuals both recommend Mopar DOT 3 for the brake master cylinder, and Jeep says the correct type is also identified on the original factory reservoir. The U.S. Maintenance Plan in those manuals does not list a mileage or time interval for replacing the fluid, so the practical answer is to check it regularly, test it at every brake job, and flush it when it is dark, contaminated or has absorbed moisture.

What Brake Fluid the 2017-2023 Compass Uses

The second-generation Compass uses a conventional glycol-based hydraulic brake system with ABS and electronic stability control, plus an Electric Park Brake switch in the center console, as described in Jeep's 2018 Compass Quick Reference Guide. The fluid specification in the "Fluids And Lubricants" table of the owner's manual is short and unambiguous:

If you own a 2017, 2018, 2019, 2021 or 2022 model, the quickest confirmation is the reservoir itself. Jeep states that the proper fluid type is identified on the original factory reservoir, which appears as the Brake Fluid Reservoir Cap in the owner's manual engine-compartment diagrams for both the 2.4L and 2.0L engines.

DOT 3 vs DOT 4 on a Compass

DOT 3 and DOT 4 are both glycol-ether fluids defined by the federal brake fluid standard, FMVSS 116 (49 CFR 571.116). The standard sets minimum boiling points for each grade, and DOT 4 has to meet higher ones:

Because DOT 4 meets or exceeds every DOT 3 boiling-point minimum and is also glycol based, it is commonly used as a step-up fluid in DOT 3 systems. Jeep's own recommendation for the Compass is still Mopar DOT 3, so when in doubt, use exactly that. What you should never do is add DOT 5 silicone fluid. The federal standard requires it to be dyed purple precisely so it stands apart from glycol fluids, and it does not belong in a system designed for DOT 3.

The owner's manual also warns never to let petroleum-based fluid contaminate the brake fluid. Power steering fluid, engine oil or transmission fluid in the brake reservoir can damage the rubber seals throughout the system, and Jeep warns this can cause partial or complete brake failure. If that has happened, a flush alone will not fix it; the damaged seals and rubber components have to be replaced.

How Often to Flush Compass Brake Fluid

The U.S. Maintenance Plan in the 2020 and 2023 Compass owner's manuals calls for inspecting the brake linings and inspecting brake pads, shoes, rotors, drums and hoses, but it does not include a line item for replacing the brake fluid. That does not mean the fluid lasts forever. It means the decision is based on condition.

Glycol brake fluid is hygroscopic: it pulls moisture out of the air over time. ADVICS, an OE brake supplier, notes that the wet boiling point is measured on fluid that has absorbed 3.7 percent water by volume. Compare the two boiling-point columns above and you can see what moisture does: the DOT 3 minimum drops from 401 F dry to 284 F wet. ADVICS also advises basing replacement on the owner's manual rather than a universal timeframe, which for the Compass means inspecting and testing rather than following a fixed calendar.

A sensible approach for a Compass owner:

• Check the level whenever you are under the hood. The manual says to check it during under-hood services and immediately if the Brake Warning Light comes on.
• Test the fluid at every pad or rotor job with a moisture test strip or an electronic tester. If it tests poorly, flush it.
• Flush it if it looks dark or murky. Discolored fluid is a warning sign that it is past its useful life.
• Test more often if you tow, drive long mountain grades, or live somewhere humid, since heat and moisture work together against the fluid.

Symptoms of Old or Low Brake Fluid

The Compass Brake Warning Light monitors fluid level as well as parking brake application. Jeep explains that the light turns on when the fluid level in the master cylinder drops below a specified level, and that it may flash momentarily during sharp cornering because the fluid level shifts. Signs to act on:

• Brake Warning Light on with the Electric Park Brake released: check the reservoir level first.
• Soft or spongy pedal, especially after repeated hard stops. Moisture-laden fluid can boil and form vapor, which compresses under your foot instead of pushing the pistons.
• Pedal that fades on long downgrades and recovers after the brakes cool.
• Fluid level dropping steadily. Jeep notes that the level is expected to fall as disc brake pads wear, but that a low level may also be caused by a leak.

Because the level falls naturally as pads wear, do not top the reservoir back up to the brim on worn pads. When new pads go in and the caliper pistons are pushed back, that fluid returns to the reservoir and can overflow.

Topping Off and Flushing: What the Job Involves

Topping off is simple. Clean the top of the master cylinder area before removing the cap, as the manual instructs, add fresh DOT 3 to the level described on the reservoir, and keep the cap secured. Jeep specifically warns against overfilling, because brake fluid spilled on hot engine parts can catch fire, and against letting it contact painted or vinyl surfaces, which it damages. Use only new fluid or fluid from a tightly closed container; FMVSS 116 requires every bottle to carry the warning to keep it clean and tightly closed to prevent moisture absorption.

A full flush means bleeding each wheel until clean fluid comes out, working through the wheels in the order the factory service procedure gives, while never letting the reservoir run dry. On a Compass with ABS and electronic stability control, air that gets into the hydraulic control unit may require a scan tool to cycle the ABS valves during bleeding, so if the reservoir was run empty or the ABS unit was opened, follow the factory service procedure or have a shop with the right tool do it. For a routine flush where the system never ran dry, a pressure bleeder or a two-person manual bleed is a driveway job for someone comfortable working on brakes.

What to Do at the Same Time

The best time to flush the fluid is during a pad or rotor job, because the calipers are already accessible and you will be pushing pistons back anyway. If you are doing a brake job on a 2017-2023 Compass, our 2017-2023 Jeep Compass and Renegade front ceramic brake pads are listed for this generation. Also look at:

• Brake rotors if the existing ones are scored, worn below minimum thickness, or cause pulsation.
• Brake hardware kits so the new pads slide freely in the caliper brackets.
• Brake hoses if any are cracked, swollen or seeping; the maintenance plan asks you to inspect them.
• Brake calipers if a piston is sticking or a dust boot is torn, since a torn boot lets dirt and moisture reach the piston.

Frequently Asked Questions

Can I use DOT 4 in my Jeep Compass?

DOT 4 is glycol based and meets higher boiling-point minimums than DOT 3 under FMVSS 116, so it is widely used as an upgrade in DOT 3 systems. Jeep's written recommendation for the 2017-2023 Compass remains Mopar DOT 3, so that is the safest choice if you are unsure.

Can I use DOT 5 brake fluid in a Compass?

No. DOT 5 is silicone based and dyed purple by federal rule so it is not confused with glycol fluids. The Compass system is designed for DOT 3.

How often should I change brake fluid on a 2017-2023 Compass?

The U.S. owner's manual Maintenance Plan does not give a set interval. Test the fluid at every brake service and flush it when a moisture test fails or the fluid is dark, and test more often if you tow or drive in heat and hills.

Why is my Compass brake warning light on?

With the parking brake released, a common reason is low fluid in the master cylinder from worn pads or a leak. If the fluid is at the full mark and the light stays on, Jeep says it can indicate a brake hydraulic malfunction or a brake booster problem detected by the ABS/ESC system, and it should be inspected as soon as possible.

Where do I add brake fluid on a Compass?

At the brake fluid reservoir in the engine compartment. The owner's manual engine-compartment diagrams label it as the Brake Fluid Reservoir Cap for both the 2.4L and 2.0L engines. Clean around the cap before opening it.

Sources

1. 2020 Jeep Compass Owner's Manual (Mopar) - Mopar DOT 3 recommendation, brake system warnings, Maintenance Plan, Brake Warning Light
2. 2023 Jeep Compass Owner's Manual (Mopar) - Mopar DOT 3 recommendation, 2.0L engine compartment, Maintenance Plan
3. 2018 Jeep Compass Quick Reference Guide (Mopar) - Electric Park Brake
4. 49 CFR 571.116, FMVSS 116 Motor Vehicle Brake Fluids - DOT 3, 4 and 5 boiling points, container moisture warning, DOT 5 purple color
5. ADVICS - Brake Fluid Boiling Points - hygroscopic fluid, wet boiling point at 3.7 percent water, vapor lock