The Polaris RZR is a popular side-by-side, but it does come with its share of problems. Overheating is one of the most common issues that drivers face with this vehicle, but it’s relatively easy to diagnose and fix.
Your Polaris RZR may be overheating due to a malfunction in the coolant system, filtration system, or even a dirty radiator. Fixing it requires cleaning the air filters and radiator, purging the coolant system of air, and turning off the vehicle when idle.
I’ll walk you through all the steps you need to go through to diagnose and fix the overheating issues you have with your Polaris RZR. Follow these steps, and you won’t go wrong.
1. Clean the Radiator
Over time, you’ll find that your radiator has accumulated a lot of dust which would interfere with the cooling system of your Polaris RZR. Dust acts as a thermal insulator, locking heat inside the radiator, thereby not allowing the engine to ‘cool off’ as needed.
In any case, it’s simple enough to clean your ATV’s radiator. A pressure washer is the perfect tool for the job if you stand far enough to avoid bending the fins. I found the Sun Joe SPX3000 (link to Amazon) worth the expense. It’s easy to handle and packs a lot of power for such a small washer.
Here’s how to clean the radiator of your Polaris RZR:
- Turn off the engine.
- Remove the radiator cover and carefully set it aside.
- Load your pressure washer with plain water and a small amount of detergent (optional).
- Standing 4 to 5 feet (1.2-1.5 m) away, start up your pressure washer.
- Aim the pressure washer at the radiator fin, taking care not to direct the water at an angle so as not to bend the fins.
- Turn off the pressure washer and give the vehicle time to dry a little before running it.
- Put back the radiator cover before running the engine.
2. Clean Your Dusty Air Filters
Another way that dust can cause overheating is by clogging air flow through air vents. After all, airflow is an essential part of any engine’s cooling system (source). Even if you don’t live in a particularly dusty area, you might find that your air filters are clogged—causing the engine to overheat.
It is highly recommended that you regularly clean your air filters to avoid dust accumulation and clogging. Cleaning the air filters is easy enough:
- Disassemble the air filters.
- Wash the air filters using water and mild detergent. A 2:1 ratio of water to laundry detergent works well.
- Allow the air filters to dry thoroughly before reinstalling them.
- Reinstall the air filters.
3. Check Coolant Levels
More often than not, people forget that their Polaris RZR is still an engine that requires regular maintenance. You’re advised to periodically check the coolant levels to ensure that the cooling system is working properly. Otherwise, you’ll have to deal with overheating and all the problems that come with it.
If there is not enough coolant in the system, the engine will not be capable of cooling down, and consequently, it will overheat. Luckily, checking (and adjusting) the coolant levels in your Polaris RZR is relatively simple. Here’s a quick step-by-step guide:
- Turn off your engine and wait for it to cool down completely. Otherwise, you run a very high chance of burning yourself from steam exiting the engine as coolant is poured in.
- Remove the hood panel.
- Open the pressure cap of the radiator’s overflow bottle (source).
- Check the coolant level. There should be an overflow line to show you how much coolant you need to have in the system.
- If the coolant is below the level of the overflow line, add coolant until it reaches that level. Otherwise, leave it be.
4. Bleed Air Out of the Cooling System
This might be one of the trickier fixes for overheating issues, but it’s important to check nonetheless. Sometimes the cooling system has air circulating inside, preventing coolant from flowing freely. To remedy this malfunction, you will need to purge air out of the system.
You’ll need to find the bleeder screw and have extra coolant on hand. Here’s what you’ve got to do:
- Fill the cooling system’s reservoir with sufficient coolant, ensuring that the coolant levels are above the overflow line.
- Locate the bleeder screw. It’s an 8 mm (0.3-in) screw, usually found right above the exhaust.
- Rotate the bleeder screw a quarter turn.
- Tighten the screw back up once you have a steady flow of coolant (after air) coming from the screw.
- Top up coolant to adjust the level as needed.
- Fire up your engine, keeping an eye on the temperature gauge.
- Repeat the process if the temperature spikes too high (above 190°F/87.8°C) too fast.
Note: To avoid steam burns, do not repeat the process if the temperature gauge reads anything higher than 185°F (85°C).
5. Let the Engine Rest
Sometimes the engine overheats from sitting idle for too long. This is a problem that comes with such a small engine that you’ll just have to deal with. The simplest solution to overheating from an idling engine is to simply turn it off whenever possible.
It may seem like a nuisance, but turning off the engine when your ATV will be idle for more than five to ten minutes makes a world of difference. If you do notice that the engine often overheats when idling, it may be worth it to change the radiator fan.
It’s particularly important to change the radiator fan if you notice that the engine overheats when idling, and then the temperature gauge dips again once you drive the vehicle.
Do not attempt to change the radiator fan alone—some things are best left to the professionals. I wouldn’t recommend replacing or fixing the radiator fan yourself because there are too many variables and ways you could damage the engine if not done right.
And that’s it! At some point, you may also run into trouble with the speedometer not working. Click on the link to read my guide on why the issue happens and solutions to fix it.
Although the Polaris RZR provides a great balance between power and versatility, overheating problems are common. Taking the proper precautions to ensure that the engine doesn’t continue to overheat can save your engine from major (irreversible) damage.