The mysterious case of the lost coolant
Audi are known for their racing pedigree in the Rally scene and their all-wheel drive system, named Quattro. The modern-day Audi RS4 is the top-of-the-line performance saloon that incorporates the latest in all-wheel drive technology, whilst being packed with features, high performance, and practical enough for transporting your family.
With over 400 horsepower, the 2020 RS4 not only performs and handles exceptionally well, but it also looks the part. With a low-slung body style, and smooth aerodynamics and that angled front end, it is the ultimate 4-door Audi.
In order for that powerplant to operate to its full potential, the coolant system needs to intricately feed freshly cooled liquid through the engine and turbo systems. When it is not working, it can be troublesome for the owner, with the potential to cause engine overheating and failure on these RS4’s, causing expensive repair bills.
At Links Automotive, we are Audi Specialists and were graciously presented with a fine example of the 2020 RS4 from Mr H. Despite no evidence of leaky coolant, there were a host of dashboard warning messages, the level had been dropping significantly, and the car was misfiring.
Luckily, our Audi specialist technicians were on hand to attend to Mr H’s RS4 quickly, preventing further possible damage to his expensive Audi. Aaron White, an expert in his field, looked forward to tackling this mysterious case of missing coolant and began going through extensive checks on Mr H’s RS4, getting to the root cause of the problem.
Finding Fault Codes and Researching…
At Links Automotive, we pride ourselves in fixing any problem quickly and efficiently. As an Audi specialist, we’ve seen and done it all. Using only the best specialist Audi technicians with years of industry experience to tackle our customers problems. As the last thing you want is to be hanging around whilst your car gets fixed, then waiting even longer for a new part to arrive, or still having an issue when you leave the garage.
To begin with Mr H’s RS4, Aaron used his knowhow to visually inspect all parts of the cooling system to check for leaks and coolant deposits. The next step after checking all the undertrays, the floor, the pipes and the coolant system components was to use the Audi specialist dealer approved diagnostics equipment to scan for fault codes.
The scan using the Audi garage ODIS dealer tool proved that Mr H’s car had misfiring on 2 cylinders. This additional information made Aaron think differently about the problem with Mr H’s RS4, as we explain shortly.
Aaron thought there was clearly something else wrong and the cooling system was causing this fault code, especially when Mr H mentioned that he needed to keep topping up the reservoir.
Going further into investigations Aaron used his automotive industry knowledge to fully test the coolant system. Firstly, he pressure tested the coolant system to prove no leaks, with a visual inspection of the heater matrix to further prove the lack of leaks coming from any of the units.
As Audi specialists, we also consulted a host of online research in the form of Audi Manufacturer Bulletins to narrow down the issues that Mr H’s RS4 had. Aaron had found several complaints regarding the charge air cooler needing attention due to a fracture in the walls of the unit, causing internal leaking.
Aaron wasted no time in pulling apart the necessary trim and engine components to get to the charge air cooler. This proved that there were no initial signs of coolant on the boost pipe into the cooler, but evidence of coolant within the cooler and deposited on the outlet boost pipes, proving the Audi bulletin investigations.
After finding the charge air cooler unit at fault, Aaron wanted to understand for Mr H why the fault codes of misfiring in two cylinders. It turns out that the charge air cooler was feeding small amounts of coolant into the cylinders during the combustion process, affecting it in a way that caused this misfiring.
Replacing the Charge Air Cooler
As a result of Aarons detailed investigations, he informed Mr H that the charge cooler needed replacing. Immediately upon his approval, Mr H’s new part was ordered in and worked on. Being an RS4 Specialist, we at Links Automotive tapped into our parts network immediately and sourced a new air charge cooler in no time.
Removing the existing charge air cooler meant draining the coolant system, disconnecting the feed pipes, unbolting the old unit, and fitting the new unit. We also go the extra mile and cleared out the coolant residue on the outlet boost pipes for Mr H, leaving him with a shiny looking cooling system around the charge cooler. The car was filled up once more with coolant, the system was properly bled of air and then test driven by Aaron to check for any further issues.
Luckily there were none for Mr H’s Audi and after Aaron cleared the misfire fault codes, he was able to hand back the RS4 to its rightful owner.
Mr H Trusted Our Expertise
As an Audi specialist garage we pride ourselves on our service and better-than-dealer value. This is because our Audi specialist technicians have extensive knowledge in all types of RS4 vehicle repairs. This included Air Conditioning, Electrical, Emissions, Safety, Engine, Suspension, Brakes and much more.
This means we are able to turnaround our Audi services and repairs quickly, and with the latest in dealership diagnostics and equipment, replacing parts such as the charge air cooler was completed in a matter of hours. Letting Mr H get back on the road with his fully repaired Audi in no time.
At Links Automotive, we made sure that we informed Mr H about his Audi during the repair process. Besides, a misfiring, coolant leaking, warning message ridden car is the last thing owners want for their performance all-wheel drive Audi, especially with Mr H’s model being just two years old at the time.
Hundreds of customers rely on us each month at Links Automotive. We are Audi RS4 specialists and no matter what the fault, our technicians are experienced in strict standards and get you back up and running as soon as possible.
We provide guidance to every customer that comes into our workshop. Mr H was informed on each step we took to identify the charge air cooler fault, including asking permission to order in the new cooler and work on his vehicle.
If you need to fix your Audi engine misfiring because of that pesky charge air cooler, require an Audi service or have any other Audi vehicle issue, contact us today on 01625 402262 to book an appointment. We at Links Automotive are Audi specialists and have expert technicians ready to work on your vehicle.
