BMW overheating

BMW overheating: Possible causes and how to prevent it

In Cooling System, Maintenance by Steves Auto Repair and Tire

BMW overheating problems aren’t uncommon occurrences.

We worked on a 2004 BMW that was brought in multiple times because it was overheating. 

When it first came to Steve’s Auto Repair, our technician noticed that it was low on coolant. He performed a pressure test on the cooling system and discovered the coolant reservoir was cracked.

Refrigerant cools a vehicle’s engine. It flows from the engine to the radiator, where some heat dissipates. The coolant then goes back to the engine.

Without coolant, the heat is confined to the engine.

Because the car couldn’t keep its coolant, we weren’t able to complete the diagnostic testing. 

The coolant reservoir was replaced, but the BMW was still overheating. 

Brian performed another pressure test to confirm there aren’t any other leaks. When he didn’t see any, he determined that the issue was with the thermostat or water pump.

Through further investigation, Brian noticed there was a difference in the temperature of the upper radiator hose and lower radiator hose, which usually indicates a bad thermostat.

The thermostat was sticking closed, preventing coolant from reaching the radiator and cooling the vehicle down.

Possible reasons behind a BMW overheating

Being low on coolant is the most common reason a BMW overheats. This is the result of a coolant leak. The technicians at Steve’s Auto Repair & Tire are able to look for and address coolant leaks.

Overheating can also indicate a thermostat issue. If the thermostat doesn’t open, coolant isn’t able to flow to where it needs to go.

A car could also overheat due to an electrical component, such as the electric cooling fan and electric cooling fan controller. Even a module or computer may be experiencing an issue that prevents the cooling fan from turning on. 

We have worked on vehicles that had functioning cooling fans that weren’t spinning fast enough to pull air through.

How to prevent your car from overheating

Some overheating problems can’t be avoided. However, there are some maintenance options available.

Coolant fluid exchanges, for examples, can help prevent the engine from overheating. It also extends the life of the cooling system components and overall life of the engine.

You can read more about coolant fluid exchanges in this article we wrote recently.

We recommend this service every 30,000 miles. Depending on a manufacturer’s recommendations, a vehicle could require it more often.

You might want to also consider a coolant fluid exchange if work is being done on the thermostat or you’re getting a new radiator or water pump. 

Depending on how much and where you’re driving, debris – such as dirt, bugs and grass – can start to build up in front of the radiator.

Getting it cleaned out to make sure the air is flowing through to the radiator can keep a vehicle from overheating.

Steve’s Auto Repair & Tire is an authorized Goodyear tire dealer located in Woodbridge, Virginia. Automotive repair services are performed on all makes and models, including BMW and Mercedes. Services include oil changes, brakes, alignments, inspections, and computer engine diagnostics.