Brown Sludge in Radiator Reservoir and Very little coolan...

Q: Brown Sludge in Radiator Reservoir and Very little coolant

asked by on June 14, 2017

brown sludge in radiator reservoir. I have a 2002 passat 1.8t. Nothing is mixed in with the oil. My father flushed the coolant system, first thing this morning and I drove my other car to work. We let the car run for a few minutes and the radiator reservoir was clear. I came back after work ( approx 8 hours: don't know if it matters), started the car and the check coolant light came on immediately. Checked the reservoir and there is was again. Coolant overflowed everywhere the first time the brown sludge happened and got on a lot of stuff, so I couldn't tell if the white smoke was coming from my tailpipe or if it was burning off because things were hot. No sign of oil leakage either. I did refill coolant the first time the coolant came on but I did not take in consideration the type of coolant and mixed coolants. Also my dad drained the radiator and poured water in the reservoir to flush. I figured you would have to let the water run through the system to completely get all the sludge

My car has 169000 miles.
My car has an automatic transmission.

Brown sludge could be a consequence of mixing incompatible coolants as well as not draining the coolant frequently enough. At this point, you just want to be sure that as much of the contaminants as possible have been removed and re-introduce the correct coolant for your vehicle. If the coolant level was low and you are having to periodically top off the system, that means there is a leak and, if so, that should be repaired. If you suspect a leak, to get the required repair estimated, please request an engine cooling system leak diagnostic and the responding certified mechanic will get this resolved for you. If you want the system thoroughly cleaned and the correct antifreeze added, just request a cooling system flush. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Car won't start after driving any distance. I have to let it cool down before I can start the engine again.

It's curious that you don't seem to have a code in the ECM. Usually if you have a malfunction that prevents the car from starting, there will be a code resulting. That being said, it sounds like you may have...

The car is misfiring.

Hi, thanks for writing in. There are many things that could cause a misfire, such as faulty spark plugs, a bad coil pack, bad injectors, a faulty crank position sensor or something else. I would recommend having an expert from...

What is causing the engine misfires?

It is usually best to change all the coils when chasing a misfire with engines of this age and mileage. If one is weak, they are likely all weak. When you changed the plugs, was there oil in the spark...

Related articles

Volkswagen Certified Pre-Owned (CPO) Car Program
Drivers Drivers in the market for a used Volkswagen vehicle may want to check out cars under their certified pre-owned program. Many manufacturers have a certified pre-owned (CPO) program, and each one is set up differently. Read on to learn...
A Buyer's Guide to the 2012 Volkswagen CC
At At some point, most of us have to choose between the cars we wanted when were kids and the ones we need for our commute to the office or to pick up our own children. With the 2012 Volkswagen...
A Buyer’s Guide to the 2012 Volkswagen GTI
The The 2012 Volkswagen GTI has a good suspension offering a smooth drive on any type of pavement. The interior feels luxurious because of the high quality materials used for the seats and the overall unique design of the vehicle....