temp gauge takes too long reach 90,and also drops

[vw754]

my A5 2.0 tdi takes a good 15 minutes drive to get upto temp.........well it dont exactly make it to 90........it sits below 90 and if i put heaters on it drops to around 80..........what can it be,it use to get to 90 in no time,and even with the heaters on,it use still sit at 90 but now its not getting to 90 ,sits just under.

i suppose this affects my mpg too to some degree ?

 

[KrisKrk]

Similar happens to my 2.0.
I need good 5-6 miles drive for it to reach 90, without heaters on.
Soon as I switch them on it drops slightly but creeps back up with further drive.
If I drive with heaters on and 90 wasn’t reached, it will take even longer to get there.

Alternative to my issue is motorway. Pushing the car to 70-80 mph will bring up the temp much faster.

Noticed that, if driven longer on lower gears, with steady speed (20-25 mph on 3rd) will obviously speed up reaching 90.

If I get solid 90 for few minutes and than put the heaters on, it will stay there.

Regardless what I do, temp gauge will start to jiggle when stationery for longer.

Read somewhere that, it is the winter time and diesel engine to blame.
This also explains black cabs cardboard on the grille, during cold weather.

Your problem looks like stuck stat. Engine cannot reach and maintain the temperature as the thermostat might be open.
Or, it opens earlier than it should. That would indicate possible fault with temp sensor around the stat and it opens it too soon.

Have you run any scans (vcds or similar)?


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[Jemster]

My A4 177tdi is exactly the same. Dealer says it’s normal, but I’m sure it doesn’t help with the poor economy. I rarely manage to get the car up to temperature at the moment. Really hope this improves as the weather warms up as I’m sure it can’t be good driving everywhere on a cold engine, for the engine or the pocket!

Checked the oil temperature too (lap timer) just in case it was only the water temp fluctuating and it’s no better. No error codes either but it really does sound like a thermostat issue.

 

[Meemo]

classic thermostat stuck open My 2.0tdi did the same last year (would sit just shy of 90 in the 80 mark fluctuating a little, prior to that for 4 years was 90 bang on always), was a cheap fix to replace the thermostat and new fluid, golf petrol also did the same, they are pretty common to go on most cars, thankfully nothing too taxing to sort.

 

[KrisKrk]

I had my stat changed last year Feb and it was fine. Only winter started it came back again.
Is it possible for it to be stuck again, after nearly a year?

Guy who change it for me, showed me 4 or 5 stats before he got the right one to match.
Would it be the case of bad batch or aftermarket part?


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[Jemster]

I'd love it to be a stat issue, but from what I've read (searching around for temperature and economy issues) it would appear it is normal for this engine.

My car went in to the dealer as my economy is **** and I suggested it was the thermostat as it seemed to take an age to get up to temperature. I chatted with the mechanic when we went for a test drive beforehand and he agreed it sounded like a stat issue, but when I collected it they had tested and it's fine, Audi have some kind of tech note about it. I've read other posts / forums where people have changed the stat only to get the exact same result in the winter. The engine apparently just doesn't generate enough heat to warm itself up.

The car's only done 38k and less than 3 years old, isn't it a bit early for a stat failure?

How easy is it to remove the stat, test it and put it back in? (Not that I don't trust the dealer of course ) I've still got a few months warranty left and if there is an issue, I'd like to sort it out, dealer or not.

Although thinking seriously about moving this car on as the fuel economy is so incredibly poor. 4th tank and I've managed 36.1, 26.8 and 28.0 mpg with the first 3. The only reason I got 36.1 is because I cruised for 200 miles on motorway at 65-75.

I was getting better out of a '98 BMW 323i and only about 25% less in an '05 M3 on the same journeys!

 

[Meemo]

I had my stat changed last year Feb and it was fine. Only winter started it came back again.
Is it possible for it to be stuck again, after nearly a year?

Guy who change it for me, showed me 4 or 5 stats before he got the right one to match.
Would it be the case of bad batch or aftermarket part?


Sent from my iPhone using Tapatalk

Haha funny you say that, my golf 1.8t went through 2 in a year and a new temp sender, the second thermostat i used a generic third party one rather than a gen and it was fine and as far as I am aware sold on with no further issues to the new owner

I am not so sure it is 'normal' standard behaviour on the 2.0 tdi (170).. i had this engine on the audi i owned for the last 5 years and only sold last month, it only ever happened the month my thermostat went last year, changed it and I never saw it do this again, and was not a behavior I had observed previously.

 

[Meemo]

I'd love it to be a stat issue, but from what I've read (searching around for temperature and economy issues) it would appear it is normal for this engine.

My car went in to the dealer as my economy is **** and I suggested it was the thermostat as it seemed to take an age to get up to temperature. I chatted with the mechanic when we went for a test drive beforehand and he agreed it sounded like a stat issue, but when I collected it they had tested and it's fine, Audi have some kind of tech note about it. I've read other posts / forums where people have changed the stat only to get the exact same result in the winter. The engine apparently just doesn't generate enough heat to warm itself up.

The car's only done 38k and less than 3 years old, isn't it a bit early for a stat failure?

How easy is it to remove the stat, test it and put it back in? (Not that I don't trust the dealer of course ) I've still got a few months warranty left and if there is an issue, I'd like to sort it out, dealer or not.

Although thinking seriously about moving this car on as the fuel economy is so incredibly poor. 4th tank and I've managed 36.1, 26.8 and 28.0 mpg with the first 3. The only reason I got 36.1 is because I cruised for 200 miles on motorway at 65-75.

I was getting better out of a '98 BMW 323i and only about 25% less in an '05 M3 on the same journeys!

not sure on the factors, contamination, radiator fluid quality etc or what, but i thought the same when my golfs one went twice, it got changed at 35k, then again a year later at 43k before the issue stopped returning. but I did use a gen stat first time and went for a cheapy generic one second time as figured the gen ones seemed unreliable.

 

[Jemster]

not sure on the factors, contamination, radiator fluid quality etc or what, but i thought the same when my golfs one went twice, it got changed at 35k, then again a year later at 43k before the issue stopped returning. but I did use a gen stat first time and went for a cheapy generic one second time as figured the gen ones seemed unreliable.

Here's the kind of thread I've been reading...

http://www.audi-sport.net/xf/threads/engine-temperature-and-warm-up-time.174595

Loathe to spend money on it, but I am coincidentally going to run out of warranty just as the weather finally warms up (end of April... I bought the car in November). Have you seen a how-to anywhere on replacing it? I see on the B7 it's only meant to be a 20 minute job, so if it's not too bad I'd give it a go myself but I'm a total doofus when it comes to this car. No idea. The last 2 BMW's, easy, loads of forums, loads of info, loads of DIY videos. This one.... not so much!

 

[Meemo]

Here's the kind of thread I've been reading...

http://www.audi-sport.net/xf/threads/engine-temperature-and-warm-up-time.174595

Loathe to spend money on it, but I am coincidentally going to run out of warranty just as the weather finally warms up (end of April... I bought the car in November). Have you seen a how-to anywhere on replacing it? I see on the B7 it's only meant to be a 20 minute job, so if it's not too bad I'd give it a go myself but I'm a total doofus when it comes to this car. No idea. The last 2 BMW's, easy, loads of forums, loads of info, loads of DIY videos. This one.... not so much!

to be super unhelpful, I did the golf but the Audi i took to my local garage but cost me something like 30 mins labour and brought my own part with me, so I suspect it should not be too difficult.. but it was cold and I was lazy haha

 

[GUNG]

Would the thermostat not getting to a steady 90 ...affect the dpf regeneration process

 

[Jemster]

Would the thermostat not getting to a steady 90 ...affect the dpf regeneration process

Don’t know, mine seems to be running regens about 500 miles apart. I don’t know if running richer when cold causes greater soot buildup perhaps?

It’d be great if there was a way of telling if the thermostat was jammed open by feeling pipe temperatures on either side of the stat. Has anyone done this?

 

[Marky007]

Any updates 5 years later ....

 

[vw754]

Any updates 5 years later ....

Lol
It was the thermostat

 

[Marky007]

Lol
It was the thermostat

Cheers buddy got manhale main thermostat for a6 c7 and a4 b8.5 both 2.0tdi may have a go at changing them tomorrow

 

[vw754]

Cheers buddy got manhale main thermostat for a6 c7 and a4 b8.5 both 2.0tdi may have a go at changing them tomorrow

Pain in the **** change.....,

 

[Marky007]

Pain in the **** change.....,

Take long? seen few YouTube videos

 

[vw754]

Videos make it look easy,do it,then let me know,it's awkward.... about 2-3 hours

 

[Marky007]

Took me 3 hours today on my a6, the plastic coolent hose at back is the hardest part forgot to disconnect battery got few sparks off alternator, my coolent tap underneath didn't empty when I turned it to drain nothing happened so just removed hose.

On the plus side car shot upto 90 1st time since owning it hopefully my mpg will improve

Got a4 b8.5 to do next

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