I don't know if I'm posting in the correct forum, but hopefully this gets the right eyes.

My brother has a 2002 BMW X5 with 130,000 miles on it and the car had been leaking oil quite some time and he finally decided to fix it. He usually services his car at a local Firestone, but they told him to go to the dealer to get the oil leaks repaired so he did. A couple thousand dollars later and no more oil leaks and the car is still running well. I have no idea what they did and my brother knows pretty much nothing about cars, so he's not too sure what they did either.

Now, here is my question. He told me that the dealer said something about there being a lot of gunk in the engine from some sort of product that had been added and that it was causing build up in other systems in the car. For example, his heaters were not working well before the repair, but after the dealer cleaned out the gunk, the heater is working properly again.

Does this make sense?
What would cause this?

My brother is not sure if Firestone has been put some additive into his car or not and wants to know how to avoid this from recurring. Keep in mind that my brother knows nothing about cars and I'm sure something was lost in the translation.

 

Its common for the crank case vent valves to go bad in those x5s. When they do, moisture builds up in the engine and forms this gunk that looks like snot. That could be what they found, but a decent tech should know what it is when he sees it and recommend it be replaced with an updated part that BMW has released.

The engine crankcase and cooling systems should not be mixing though and there should not be any gunk in the cooling system. Its possible that Firestone put some sort of stop leak in there at some point and that's the gunk they found. Generally though when gunk is found in the cooling system its from the engine overheating and the silicate from the engine getting into the cooling system.

Also, tell your brother to stop taking his car to Firestone and find a decent independent shop who knows how to work on BMWs. If he has to use the dealer at least but almost anything is better than Firestone.

 

Thanks much mcclaren,

Since he was having this heating/cooling issue, it sounds to me that it was most likely the silicate caused by an overheating engine, but what does that really mean in terms of repair? Can that gunk just be cleaned out?