That VW Passat that took me 6 hours to find a coolant leak on

I had a 2012 Passat come in last month with a slow coolant leak. Customer said they were topping it off every few days. I pressure tested it twice and nothing showed up. Then I ran the engine up to temp and still couldn't see anything. After about 4 hours of checking hoses, the water pump, and the radiator, I was about to give up. Finally I let it sit overnight with dye in the system and came back the next morning. The leak was coming from a tiny crack on the plastic coolant flange under the intake manifold. You could only see it with a mirror and a flashlight when the engine was cold. Does anyone else have a car model that just seems to hide its problems like that?

2 comments

2 Comments

terryh2010d ago

Oh man, that plastic coolant flange under the intake manifold is the absolute worst hiding spot VW ever designed (seriously, who thought that was a good idea?). That sounds like a nightmare to track down, especially after pressure testing it twice and getting nothing. I swear German engineers play a game where they see how many hours they can make you waste before you find the obvious leak. At least you didn't have to tear the whole intake manifold off just to see it, right? That would have been the cherry on top of the misery sundae.

danielb438d ago

Bet nobody's checked if that flange was from the original run where they had a bad batch of plastic that got brittle after a few heat cycles. VW quietly changed the part number but never admitted it, that stuff goes micro cracked where you can't see it without a magnifying glass.