possible faulty temp gauge a6 2.8 30 valve

yendall24

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hi all i have a problem with my temp gauge it takes a long time to reach full temp i have changed the temp sensor its made no difference i was thinking thermostat but heres where it gets tricky because if the thermostat was faulty and stuck in the open possition i would expect the oil temp to be as slow rising as the water temp ? this is not the case the oil temp rises well before the water temp gauge begins to move so am i wright in thinking that all is well other than the actual water temp gauge reading wrong every car i have had as worked the opposite of this ie water temp starts to rise followed a few mins later by the oil temp begining to rise any ideas would be very welcome also for got to mention the fuel gauge seems eratic one minute its reading just below half a tank the next it is reading just above the red area do you think this could be linked t the temp gauge problem
 
I have had the same problem with my a6 2.8q, oil temp would increase but it would struggle to keep a normal running temp - especially in the winter months on the motorway.

I found a temp solution was to put a peice of cardboard covering the radiator, thus radiator didn't cool the engine coolant as it should. this proved that I had a faulty thermostat.

Thermostat:
unfortunately the design on where the thermostat located is crazy, you have to strip the car down as if to change the cambelt. I did all of this although it took a couple of weekends to do, given the job to do again I could do it far quicker as I had no instructions to rely on. Make sure you buy your thermostat from Audi - you know its more expensive but the quality of the part makes sure your not going to strip the car down again.
 
as for the fuel gauge, you will need to use vag com to confirm whats going on, I would have thought it would be a break in the connections.
 
Had a similar problem on my 2.8 30v a few weeks ago. Even after 20 miles temp gauge would only reach 70deg.C (it only ever reached 90deg. when stopped in traffic for a long time, & then dropped to 70deg.C again when I got going). When the thermostat was removed, to my surprise, it wasn't stuck open but on testing it opened & closed at a far too low a temperature. Now, with a new thermostat, it reaches 90deg.C in 3 miles or less & stays there absolutely rock solid. Oil temp runs correspondingly higher too (around 100deg.C)
 
if it is the thermostat is it possible to change it without removing the timing belt i have read on audifans that you can do it by sliding the timing belt forward on the cam sprocket this was done on a 2.6 v6 just wondering if it is the same setup on the 2.8 v6 realy dont want to remove the timing belt it had a full timing kit fitted 30.000 miles ago
 
Yes I have personally done this, where abouts are you, I am 5 mins from the trafford centre. I could come round and give you some pointers if you want.
 
hi does any body know if a garage or main dealer would be prepared to change the thermostat this way or would they insist on removing the timing belt completely it not a big issue at the moment with the weather having warmed up but i would like to get it sorted all the same i am in salford greater manchester does anyone know of a good independant that might be prepared to take this job on anywhere in the northwest
 
Had a similar problem on my 2.8 30v a few weeks ago. Even after 20 miles temp gauge would only reach 70deg.C (it only ever reached 90deg. when stopped in traffic for a long time, & then dropped to 70deg.C again when I got going). When the thermostat was removed, to my surprise, it wasn't stuck open but on testing it opened & closed at a far too low a temperature. Now, with a new thermostat, it reaches 90deg.C in 3 miles or less & stays there absolutely rock solid. Oil temp runs correspondingly higher too (around 100deg.C)

hi did you have to completely remove the timing belt to replace the thermostat
 
Quote:
Originally Posted by DGSdale
Had a similar problem on my 2.8 30v a few weeks ago. Even after 20 miles temp gauge would only reach 70deg.C (it only ever reached 90deg. when stopped in traffic for a long time, & then dropped to 70deg.C again when I got going). When the thermostat was removed, to my surprise, it wasn't stuck open but on testing it opened & closed at a far too low a temperature. Now, with a new thermostat, it reaches 90deg.C in 3 miles or less & stays there absolutely rock solid. Oil temp runs correspondingly higher too (around 100deg.C)

hi did you have to completely remove the timing belt to replace the thermostat

Apologies for not replying earlier. There is no need to completely remove the T/B. First off, having removed everything else necessary to get to this stage, rotate the crank to set both cams in such a position that the holes & slots in the diamond shaped plates at the font of the cam pulleys are all horizontal with the slots innermost on both sides. Mark the front edges of the T/B & R/H (viewed from the drivers seat) cam pulley (I use tippex) so that you know, for peace of mind if nothing else, that the belt has not jumped teeth whilst doing the job. Secure the T/B onto the crank & L/H cam pulleys by whatever method, e.g. cable ties, or be very careful the belt doesn't come off them or jump teeth (good idea to mark these too). Release the tension on the belt & secure the hydraulic tensioner with a small retaining pin (I use an allen key) through the hole. Remove the tensioner pulley. Slide the T/B about halfway off the R/H cam pulley for access to the thermostat. I put a couple of cable ties on this also, to make sure it won't come off any further.
Those that have access to Elsawin will note that it states 'Timing must be re-adjusted if toothed belt has slipped off tensioning roller'.
As long as the belt stays on the L/H cam & crank pulleys (staying in exactly the same teeth ) & the belt stays on the R/H cam pulley in exactly the same place (tooth to tooth) then the tension is retained correctly around the whole belt when the tension is reapplied.

HTH

Dave
 

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