This Mercedes-Benz CLA came in for a check. We found a coolant leak and an engine oil leak at the same time, and a cracked CV boot the next morning. Here is what we found, what we replaced and what it cost.
Job completed: June 2026
| Car | Mercedes-Benz CLA (an ageing car) |
|---|---|
| Symptom | Booked in for a check; a coolant leak and an engine oil leak were found |
| Fault found | A coolant leak and an engine oil leak; a fault code pointing to the oil pump; a cracked front CV boot found the next morning |
| Repair done | Replaced the coolant spare tank with cap, top and bottom hoses and thermostat, with fresh coolant; replaced the lift solenoid, end cover, oil cooler with filter housing and oil pump valve set; replaced the cracked CV boot; engine oil and filter service |
| Parts | Quality OEM-grade parts |
| Time taken | Timeline confirmed when you book |
| Cost | About $2,950 with GST for the coolant and oil leak repairs, the CV boot and servicing |
| Warranty | No warranty term for this job |
The owner booked the CLA in with us on a friend's recommendation and asked us to check the car. The leaks on this page were found on our check.
Two leaks at once is not unusual on an older car, because the parts that seal coolant and the parts that seal oil all age in the same heat.
The car is a Mercedes-Benz CLA, a compact four-door coupe with a turbocharged engine packed tightly under the bonnet. The cooling system on these cars runs coolant through a plastic expansion tank, a set of rubber hoses and a thermostat housing, all sitting close to a hot engine. The engine oil is sealed by gaskets and housings in the same hot space, including the oil cooler that sits between the oil and coolant sides.
Heat ages every one of these parts. On a car that has covered a fair few years in Singapore traffic, the coolant parts and the oil seals can start leaking at around the same time. That is the picture we found here, which is why both jobs landed together.
For a coolant leak, our standard process is a pressure test of the cooling system, because chasing the one wet spot you can see is guesswork. On a Mercedes-Benz we pair the pressure test with XENTRY, Mercedes-Benz's own diagnostic system, to read the fault memory before we commit to a scope.
On this CLA, our check found a coolant leak and an engine oil leak. We quoted the coolant side (the spare tank with cap, both spare tank hoses and the thermostat) and the oil side (the lift solenoid, an end cover, and the oil cooler with the oil filter housing), and the owner approved. For the oil leak, we advised replacing those parts first, then monitoring for any leak that remained.
Shortly after, a fault code pointed to the oil pump, so we added the oil pump valve set, and the owner agreed. Fresh coolant and an engine oil service were added to the job too. The next morning we found the front driver-side CV boot cracked, with its grease leaked out until dry. We sent the owner a photo and the price, and the owner went ahead.
Heat is the enemy of sealing parts. Singapore traffic keeps a turbo engine hot, and the cooling system runs through thousands of heat cycles. The plastic expansion tank goes brittle, the rubber hoses harden and crack, and the thermostat housing loses its seal. Once one coolant part starts to weep, the others are usually close behind, because they all aged in the same heat.
Oil leaks come from the same story. Seals and housings on the oil side sit in hot oil and harden over the years until they seep. A CV boot ages too: rubber perishes, splits, and lets the grease out. None of this means the owner did anything wrong. It is normal ageing on an older continental car. The danger is leaving it, because a coolant leak that runs the tank dry can overheat and damage the engine, which is a far bigger bill than a tank, hoses and a thermostat.
We did the coolant and oil work in one go, because opening the car up twice makes no sense when several parts are already tired.
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 job, including the CV boot and the servicing, came to about $2,950 with GST. Then the car was ready for collection, with our advice to monitor for any oil leak that remained.
In early July, the owner told us a sound from underneath the car had come back. We asked the owner to drop by so we could check it.
From our team's record of this job. Number plates are pixelated.
The cost of a Mercedes-Benz CLA coolant and oil leak repair in Singapore depends on how many parts are leaking and how deep the job goes. So we check the leaks first and quote on what we find. 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 were replaced, on top of the lift solenoid, end cover, oil cooler with filter housing and oil pump valve set, plus the cracked CV boot we found during the work. Each addition was quoted to the owner before it was done. We check the leaks and quote before any work begins.
You cannot stop a hose, a thermostat housing or an oil seal from ageing in our heat, but you can catch it early. Glance at your coolant tank now and then, and look under the car for fresh spots, coolant as well as oil. A small weep caught early is a cheap part. The same weep ignored can run the tank dry and cook the engine, which is the expensive outcome.
If your coolant keeps dropping and you are topping up often, do not just keep adding fluid. That is a leak telling you something. Have the cooling system checked so the source is found properly. The same goes for oil spots and for a cracked CV boot, which throws grease and lets dirt into the joint. Use the correct coolant and oil, change them on schedule, and act on the early signs before a small leak turns into an overheat.
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 1,836+ Google reviews.
WhatsApp us your car model, year, mileage and a photo of the leak or the low coolant tank. We'll tell you where it is likely coming from and what it costs before any work begins. Every repair is road tested before you collect.
It depends on how many parts are leaking. A single hose or seal is a small job. A multi-leak repair costs more. This CLA had the coolant tank, hoses and thermostat replaced, plus the lift solenoid, end cover, oil cooler with filter housing and oil pump valve set, a cracked CV boot and servicing. It came to about $2,950 with GST. We check the leaks and quote before any work begins.
Coolant loss usually means a leak somewhere in the cooling system. On an ageing car, the parts that leak in the heat include the plastic expansion tank, the rubber hoses and the thermostat housing, and more than one can leak at once. A pressure test shows where it is leaking instead of guessing from the one spot you can see.
No, not if the tank is running low. If the coolant drops too far the engine overheats, and an overheated engine can mean a far bigger repair than a tank, hoses and a thermostat. If your coolant warning is on or the tank keeps emptying, stop topping up and get it checked.
Both come from parts ageing in a hot engine bay. When a coolant leak and an engine oil leak turn up at the same visit, it makes sense to do them together. You open up the car once, fix everything properly, and avoid paying labour twice.
On this Mercedes CLA the work included servicing. The time depends on how many parts are leaking and need replacing. We confirm the timeline once we have checked the leaks and seen the full scope.
Yes. We pressure test the cooling system to show where it is leaking, and we diagnose the car with XENTRY, Mercedes-Benz's own diagnostic system, to read the fault memory. Then we show you what we found and quote before any work begins.
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