Mercedes-Benz CLA Losing Coolant and Seeping Oil: How We Found and Fixed It

The owner's Mercedes-Benz CLA was losing coolant and dropping oil. The coolant level kept falling, and topping it up was not holding for long. At the same time there were oil signs showing, so the engine was weeping oil as well.

Two leaks at once is more common than people think on an older car, because the parts that seal coolant and the parts that seal oil all age in the same heat. The owner did not want to keep guessing or keep topping up fluids. The ask was simple. Find every leak, fix it properly, and get the CLA back safe to drive.

We started by checking the cooling system for where it was losing coolant, because chasing the one wet spot you can see is guesswork. With the system checked under pressure the coolant leaks showed themselves around the spare tank, the hoses and the thermostat area. It was not one single leak. It was a tired cooling system weeping from a few points, which is why topping up never held.

With the car on the hoist we also went over the engine for the oil leak. We cleaned the underside, ran the car and traced the oil to the oil cooler with its filter housing and the oil pump valve area. While the car was up we spotted something else: the front driver-side CV boot was cracked and the grease had dried out, so the joint was exposed. Mercedes diagnostics, run through Xentry, also help confirm any fault codes before we commit to a scope. We showed the owner each leak and the cracked boot before quoting, so nothing was a surprise.

We fixed the leaks at the source rather than chasing them one at a time, because opening the car up twice makes no sense when several parts are already tired.

• Replaced the coolant spare tank with a new cap, and the top and bottom spare tank hoses.
• Replaced the thermostat and refilled with fresh coolant.
• Replaced the engine oil cooler together with the oil filter housing.
• Replaced the oil pump valve set and the end cover on the oil side.
• Replaced the cracked front CV boot so the driveshaft joint was protected again.
• Carried out servicing at the same time: fresh engine oil and a new oil filter.
• Refilled, checked the system held, then road tested the car before handover.

All the replacement parts were quality OEM-grade parts. Because the coolant and oil leaks were fixed together, the owner only paid labour once to open the engine bay. The full repair with servicing came to about $2,950 with GST. After the work the coolant held, the oil leak was sorted and the car ran clean, which we confirmed on the road test before it went back to the owner.

A Mercedes-Benz CLA coolant and oil leak repair in Singapore typically runs from around $2,500 up to $4,000, depending on how many parts are leaking and how deep the job goes. This was a multi-leak job. The coolant repair, the engine oil leak repair, the cracked CV boot and the servicing together came to about $2,950 with GST.

What moves the price is the extent of the leaks. A single hose or one seal is a small job. Here the coolant tank, hoses and thermostat all needed replacing, on top of the oil cooler with filter housing and the oil pump valve area, plus the cracked CV boot we found on the hoist. Because we trace every leak first and show you what is wet before quoting, you pay for exactly what is leaking, not a blanket parts list. We check the leaks and quote before any work begins.

This Mercedes-Benz CLA (Coolant leak and engine oil leak repair) was handled at 1 Car Service, an independent workshop in Sin Ming AutoCity, Singapore. For Mercedes-Benz, we use dealer-level XENTRY diagnostics. We hold a 4.9★ rating from 1,775+ Google reviews.