Today I.....

I’ve a genuine thermostat you can have for £25 posted Barry if needed.

what time were you on the M25, I was there around 1:30 yesterday, perhaps we passed each other!
Sorry, missed this so have new thermostat coming this morning from TPS, many thanks for the offer :)
 
If 7deg difference is the best Febi can do then I will not be using one of there temp sender units
The Audi ones are normally max 2 deg difference
The thing is Paul, most of the time a decent OEM one is fine. Cobalt I and LASi both had pattern thermostats and coolant senders and were fine.

Now, if you run just one car, it's your car and you're keeping it for years then it's easy to spec genuine or better quality at every stage. My Passat has always had the very best.

When you're saving a vehicle that's truly circling the drain, you simply can't do that: a) the ultimate value won't support it, b) you are usually playing catch-up on perhaps ten years plus of sub-optimal maintenance and c) usually these cars are so bad at the beginning the whole thing is a total gamble.

Ultimately with these cars, you're not buying one part, but a dozen or more. Well, if you just go straight in replacing everything with the very best that's a hell of a gamble, especially as these cars are often not that wonderful cosmetically, have iffy history and the wrong miles.

With this in mind I take the pragmatic view: use pretty decent brand names, nearly all of the time it works out fine and if I can show they're faulty at time of fitment, I'll get a refund plus a bit for my time.

Case in point, the Bork and Beck thermostat was £11 trade and it might still be a problem with my fitting. TPS thermostat (also delivered) £31. Apply that difference at each stage and this car would now be beer cans.
 
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Ya I totally get you point Barry
It’s just the temp sensor plays such an important part in the correct running of the engine and I’ve not yet found a pattern part that is up to the job
I have used them in the past but found they either never worked correctly or one side failed after only a few months of use
I not keen on doing the same job twice even though it’s not a long or dirty job to change it out
The Audi part from Tps was about £30 and still going strong after 4 years so longer terms it’s paid for itself but I totally get your point about a do err upper and the risk of fitting lots of parts that mean the car is a total gamble
I wish I had measured the resistance on the Audi part at specific temps iced water and boiling water being the obvious ones to use as this would then be a reference point for any temp sender unit being fitted
A quick and dirty check is measure the ohms reading across both circuits of the sender unit, they should be within a few ohms if the sender unit is healthy

All the best
Paul


Sent from my iPhone using Tapatalk
 
Ya I totally get you point Barry
It’s just the temp sensor plays such an important part in the correct running of the engine and I’ve not yet found a pattern part that is up to the job
I have used them in the past but found they either never worked correctly or one side failed after only a few months of use
I not keen on doing the same job twice even though it’s not a long or dirty job to change it out
The Audi part from Tps was about £30 and still going strong after 4 years so longer terms it’s paid for itself but I totally get your point about a do err upper and the risk of fitting lots of parts that mean the car is a total gamble
I wish I had measured the resistance on the Audi part at specific temps iced water and boiling water being the obvious ones to use as this would then be a reference point for any temp sender unit being fitted
A quick and dirty check is measure the ohms reading across both circuits of the sender unit, they should be within a few ohms if the sender unit is healthy

All the best
Paul


Sent from my iPhone using Tapatalk
Yes, naturally I kept the one that came out as was mindful it hadn't been tested. Tbh I had thought that Febi would be easily good enough as a brand as it's not rocket science is it? Two thermistors of the same spec, in the same casing with the same pins. Surely you can't get that wrong. Mind you, it was VCDS showing the difference so that's not to say the sender is the reason for the two different readings.

Anyway, as the stat has to come out anyway, will drop the Febi sender out and back to back it against the original and make a judgement then.
 
Yes, naturally I kept the one that came out as was mindful it hadn't been tested. Tbh I had thought that Febi would be easily good enough as a brand as it's not rocket science is it? Two thermistors of the same spec, in the same casing with the same pins. Surely you can't get that wrong. Mind you, it was VCDS showing the difference so that's not to say the sender is the reason for the two different readings.

Anyway, as the stat has to come out anyway, will drop the Febi sender out and back to back it against the original and make a judgement then.

A dirty connection on the temp sensor plug (or anywahere up the chain) could easly cause a small difference in resistance like that. Theoretically, you can measure the sensor in-situ but it would be very awkward, unless you have a spare loom connector to plug-in and measure off those wires.
 
Sorry, missed this so have new thermostat coming this morning from TPS, many thanks for the offer :)
Out of interest how much is it from TPS?

EDIT: Just seen it was £31 - Defo an item to watch for on eBay when they come up as someone’s surplus stock etc.
 
Out of interest how much is it from TPS?

EDIT: Just seen it was £31 - Defo an item to watch for on eBay when they come up as someone’s surplus stock etc.
It was worse than that in the end, it was £32 retail, £29 to me plus VAT so £35 is, and unlike the pattern one, no O-ring either. Therefore marching up to £40 or so. And at this stage it might still be an error made by the fitter, I.e. me :eek:
 
It is biblical money when a good OEM is barely 1/3 the cost. Or to put it another way: within a tenner of the new undertray, which seemed hugely underpriced to me.
 
New rear brakes and a wheel clean after great advice from guys on here.
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I have seen in the past the thermostat fitted the wrong way round....
Of course then the symptom would be overheating as the wax (?) vial would never get hot enough to open. As it happens, most housings are nowhere near tall enough to accommodate a reversed thermostat. Fret not though, there are other ways to royally c**k it up. Go on, ask me ...

Well, since you ask ... and I will tack the following onto one of the many thermostat / temp gauge threads ....

1) Original symptom was car taking forever to warm up, BUT my interior fan wasn't working so no hard evidence of this, just a non-moving gauge. Also, the tailgate micro-switch was duff, so Mini Dis position on dash was taken by false 'boot open' warning, so no MPG at that stage as possible warning of trouble.

2) Mistake one: assume because my other A2's had needed thermostats, this one did as well, therefore failed to test the thermostat in the most basic way: feel the hoses.

3) Mistake two, despite having full fat VCDS and knowing I should do it, failed to plug it in and compare gauge and ECU readings.

4) Mistake four, buy pattern (Borg and Beck) thermostat.

5) Mistake five, fit said thermostat with supplied O-ring rather than original style seal that is more of a tyre located around rim of thermostat..

6) Test drive car: gauge still failed to register.

7) Mistake six, still failed to carry out test as per mistake two.

8) Mistake seven, swap out temp sender without doing basic resistance tests.

9) Good moves (finally) 1) Buy genuine thermostat, 2) spot old seal in workshop bin and reinstate as new stat doesn't come with one, 3) With new stat installed rig VCDS, lift idle speed with heater on full, fan off, watch VCDS instruments vs engine vs temp gauge. 4) Keep feeling hoses, now absolutely stone cold unlike before.

So the good news: whilst there is a very slight difference between engine and cluster temp sender readings, the gauge is reading absolutely identically to the engine temp side of the sender. Therefore I'm calling the Febi sender good. The old sender was tested and at ambient temps showed 1500 ohms on one side and 2500 on the other: it was duff.

Conclusion: the original thermostat was likely fine. Had I merely driven up the road for a mile and put my hand on the rad hoses I'd have known for sure.If the stat was good, the hoses would stay cold for at least a mile or so. When I fitted the pattern, in retrospect the coolant was probably leaking around the outside of it, quite aside from when it actually opened.

Therefore, the problem was almost certainly the sender. By time I had activated Mini Dis I had already messed up the thermostat, hence the dismal economy. I.e. I had literally swapped two issues over: gone from a failed sender and likely good thermostat to good sender and misinstalled thermostat.

So lessons for the future:

a) Seals aside, the pattern stat doesn't fit very well, use genuine that locks into place properly.
b) If your gauge suggests the car is failing to warm up, feel the hoses after five minutes of running: on a TDi they should still be cold. If warm, irrespective of the sender, the thermostat is either stuck open or opening too early.
3) The sender is easy to test via VCDS by comparing measuring blocks, temp, in Instruments VS same in Engine. Easier still, with unit out, start by comparing readings on the two pins next to the curve vs two pins next to the flat: if wildly different, sender is duff, if close you'll need to find actually resistance readings at particular temperatures.

Phew! Onwards I feel ...

EDIT: I forgot to say, the genuine thermostat never did open on my test and that was with VCDS and gauge saying 94.5 degrees at one point. The thermostat is labelled 89dC, but the sender is in the head, the stat is down at the base of the engine where it'll surely be cooler. Therefore I think it's safe to conclude that if your rad hoses (particularly down near the thermostat housing) have any temperature in them before the gauge shows, say, 70, you have a thermostat issue.
 
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In other news:

1) Made a shallow gutter from one of the old rear shock shrouds so as to better lubricate the gearshift tower bearings.
2) Changed the gearbox oil with a couple of litres of Euro's finest GL4/5. The fluid that came out (not really worthy of the name 'oil') was probably the original, so 204K miles old. It looked it. If the car stays it'll go six speed later so this new oil is plenty good enough for now and more to the point it's here and needs using up.
3) Lubricated front end of shifter cables.
4) found one source of noises: the car came with a hooge Mercedes battery, 100 amp-hour. This is great, but it was too big to sit down in the clamps correctly, so the bolts weren't engaged. Solution was the end clamp points (not used on our cars) were lopped off, allowing the battery to drop down correctly and therefore be tightly clamped up. Safer too.
5) Found the engine earth lead had been helpfully positioned right at the end of the gear shifter weights throw, which partly explains the dodgy gearshift and fully explains the bare copper inner in this region. Removed, cleaned everything up, reinstated discreet distance from shifter area.

All being well, will strip out much of interior tomorrow, sort the shift, de-grunge interior and put it all back together ready for another test trip.
 
Morning Barry,

Thank you for posting these two updates, I know they may seem trivial to you, hence why you’ve posted them here as you stated you weren’t sure this car merited a project thread of it’s own, but you know what? It does - I love a good “I’m saving an end-of-life vehicle (in most non-A2 folk’s eyes) from certain death” thread.

I know others do too - it helps that you write well / clearly.

If you do decide to do a thread on this car, I’d like to know how you go about lubricating / freeing up the components that will loosen up the gear change. On mine, the change is lovely and direct, however it needs a slightly firmer hand to move it forwards and backwards than I’d ideally like.
 
Today I replaced the not so orange NSR indicator lamp, fitted new number plate lamp holders as the old ones were no good due to rusty screws. I replaced the ARB drop links with some Meyle HD items, I replaced both track rod ends and removed the near side driveshaft. The offside driveshaft splines are seized solid in the drive flanges so I have invested in a hydraulic hub puller. The rocker cover gasket was cleaned thoroughly and refitted, hopefully leak free now!

More parts coming!!!
 
Today I......discovered we're back on summer diesel! I filled up this morning (after forgetting my card PIN at the pump and having to go in to pay contactless on my phone!) 20 miles later and the DIS is showing mpg in the high 70s, rather than the mid to high 60s that I've been used to for the last 6 months. Should mean I'm back to low 70s for a tank full - fingers crossed....
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I really need to get my DIS recalibrated to show the correct MPG - it's currently 10-12% over-estimating my fuel consumption, so I never see higher than high 50's MPG even though I'm getting mid-60's!
 
I really need to get my DIS recalibrated to show the correct MPG - it's currently 10-12% over-estimating my fuel consumption, so I never see higher than high 50's MPG even though I'm getting mid-60's!
Is there a procedure to calibrate the DIS?
 
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