Question re: 1.8T thermostat replacement
02-09-2009, 12:41 PM
#1
AudiWorld Super User
Thread Starter
Join Date: Nov 2003
Posts: 2,006
Likes: 0
Received 0 Likes
on
0 Posts
Question re: 1.8T thermostat replacement
I need to replace the thermostat on my wife's B5.5 Passat 1.8t, which is very similar to the B5 Audi A4. I've already changed out the coolant temp sensor to no avail, so the t-stat is next up.
<b>Here's the question:</b> Access to the thermostat on the longitudinal 1.8t seems much easier than on my TT. All the replacement DIYs I've seen on PassatWorld suggest draining the entire cooling system, but most involve thermostat and waterpump, which I'm not doing. Many in the TT forums simply pull the old t-stat, pop the new one in and seem able to do so without losing more than a few cups of coolant, so I'm thinking this should be the case for the A4/Passat too. I haven't run across any thermostat-only procedures in the A4-FAQ, so I'm asking: <b>do I need to drain the system or can I pull the old and pop in the new t-stat, only topping off the missing coolant?</b>
TIA, ~john (from the TT forum)
<b>Here's the question:</b> Access to the thermostat on the longitudinal 1.8t seems much easier than on my TT. All the replacement DIYs I've seen on PassatWorld suggest draining the entire cooling system, but most involve thermostat and waterpump, which I'm not doing. Many in the TT forums simply pull the old t-stat, pop the new one in and seem able to do so without losing more than a few cups of coolant, so I'm thinking this should be the case for the A4/Passat too. I haven't run across any thermostat-only procedures in the A4-FAQ, so I'm asking: <b>do I need to drain the system or can I pull the old and pop in the new t-stat, only topping off the missing coolant?</b>
TIA, ~john (from the TT forum)
02-09-2009, 12:56 PM
#3
AudiWorld Super User
Thread Starter
Join Date: Nov 2003
Posts: 2,006
Likes: 0
Received 0 Likes
on
0 Posts
complaint=temp gauge started reading low... details >>
In the past month or two the temp gauge started reading low, varying between between 11 and 12 o'clock on the dial. Vag-com shows the engine running between 70-72C in normal around-town suburban stuff. Idle for a while in the driveway and it will get closer to 80C but never above... start moving and it will drop back down to 69-72C.
The car has 108k miles on it, but the thermostat was replaced at 75k with the t-belt and water pump. The radiator was replaced last fall after an accident, but after 5-6k miles I'd assume the possibility of air bubble would be past us.
Yesterday, I replaced the coolant temp sensor with a spare, known-good one (from my TT) but the needle readings and Vag-Com temps remain the same.
No other DTC codes, but the MPG has dropped a bit more than usual during the winter in Chgo... I'd guess because the engine doesn't fully warm.
Sound like a thermostat to you?
The car has 108k miles on it, but the thermostat was replaced at 75k with the t-belt and water pump. The radiator was replaced last fall after an accident, but after 5-6k miles I'd assume the possibility of air bubble would be past us.
Yesterday, I replaced the coolant temp sensor with a spare, known-good one (from my TT) but the needle readings and Vag-Com temps remain the same.
No other DTC codes, but the MPG has dropped a bit more than usual during the winter in Chgo... I'd guess because the engine doesn't fully warm.
Sound like a thermostat to you?
02-09-2009, 01:07 PM
#4
AudiWorld Super User
Join Date: Feb 2008
Posts: 9,463
Likes: 0
Received 0 Likes
on
0 Posts
TJ:
I need to submit my evidence pretty soon. It'd be an added bonus to have your commentary on those pics. =) Thanks again, i'll work on getting you a few cases of root beer!
Thread
Thread Starter
Forum
Replies
Last Post
PracTTical
TT (Mk1) Discussion
13
07-10-2008 06:50 AM
FasTTr
TT (Mk1) Discussion
13
06-23-2004 02:46 PM
