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The short version is my 2004 B6 1.8t is overheating. It's got 150k on it. I did the timing belt and water pump at 100k. I used the blauparts kit. I did the thermostat, coolant flange and both temperature sensors at 145k 4 months ago to fix a leak. Been running great since. Noticed 3 days ago the fans were coming on just as I arrived at my destinations. I've since investigated and found.. no leaks as far as I can tell and I'm not losing coolant. I loosen the reservoir cap and it has a lot of pressure (aka coolant immediately overflows when hot). Heat works great. The bottom radiator hose does appear cold. And the top is certainly hot. My research obviously points to a tstat, pump or radiator. Just hoping to narrow it down from here.
I'd really appreciate some direction on where to go next. I'm sitting on the side of a busy road waiting for the engine to cool down so I can get 5 minutes back towards home.
A few more bits of information obtained from a 5 minute drive to a parking lot. The heat definitely works. The radiator is mostly cold, but the top drivers side portion.. maybe 1/20th of the total area is warm/hot. I can't possibly think the sensor is bad. The gauge seems to work exactly like I'd expect it to. It slowly warms up, sits at TDC for a minute or so, then slowly starts to inch towards the 3/4 mark. I haven't let it get to that mark yet but it gets pretty darn close.
Sure sounds like a stuck thermostat. The thermostat is located on the lower front block. When it opens it allows the coolant to flow through the lower radiator hose and into the block where the water pump pushes it through the block and out through the rear coolant flange.
If the thermostat sticks in the closed position there will be no circulation at all through the radiator. The lower radiator hose and most of the radiator will remain cold while everything else heats up.
Coolant always circulates through the heater core regardless of the thermostat position. Since you have heat you pretty much know that your rear coolant temperature sensor is reading correctly.
About 10 minutes after your response I went for it and pulled
the thermostat out. Like I said, I just did this 5k miles ago with ECS kit. I hope they refund this! I put the housing back on so I can drive to work the next few days until I can get a replacement. Thanks for pointing me in the right direction! I'd probably still be contemplating buying a timing belt kit.. any suggestions on what to replace it with? Or did I just get unlucky.
02-22-2017, 12:41 AM
Overheating
