I own a VW Golf VR6 (95N). It’s covered 110,000 miles and been regularly serviced since I purchased it new.
For the last 10,000 miles on any journey, excluding town driving, the engine records a water temp no higher than 70C when it would have normally reached 90C. There is no discernible impact on performance in fact the engine seems much smoother. Three garages (two franchises, one independent) have said the system operates within specification. The thermostat cuts in as intended to prevent overheating and there's no airlock. None conducted road tests.
Has the engine been performing to specification for the previous 100,000 miles or just the last 10,000 and does it really matter? Nobody seems to know.
Some background information you might find useful. In the last 15,000 miles, over and above normal servicing, a number of key components have failed and been replaced - the clutch; ignition pack; starter motor; temp sender; trailing arm bushes and rear discs / bearings / pads. Nothing unusual but there were problems during and following the clutch change.
At the time of the clutch change I failed to leave (never asked) the dealer with the key to isolate the alarm system (Scorpion 5000). On disconnecting the battery to undertake the clutch change the alarm activated on its backup system. After a while the engineer and other dealer staff became fed up with the noise (130db) and decided to deactivate the alarm by alternate means - never fully explained.
On collecting my car it was not possible to unlock the car electronically with either set of keys. They needed re-programming. The odometer had lost all details of the car's mileage and many wasted weeks of the dealer attempting to retrieve the data by interrogating the ECU resulted in nothing. The cabin alarm klaxon also wouldn't activate - now fixed. The dealer has since fitted a new dash insert at their cost. Both old and new temp gauges record similar water temps so I assume both operate/d correctly. ABS has also started playing up even after fitting new sensor to rear offside wheel.
Any thoughts? A friend in the computer industry suggested that the ECU could have been affected by incorrect isolation of the alarm – power surge. ECU websites suggest inadequate earthing at key moments after the clutch and starter motor changes could be the cause. Should I be concerned about these readings and if so, how should I go about rectifying the problem which no garage seems to perceive as important?
Despite the problems I'm very attached to this car. It still goes like a train, returns 30+ mpg on motorway journeys and has only broken down once. Many say get rid of it but I'm disinclined to do so unless the bills are going to start spiralling in which case it might make good sense.
Any thoughts or suggestions on the temperature problem?
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Engine thermostat sounds like it stuck as it shouldn't open till approx 92-97C. The rad fan switch is what i think you term the thermostat( thermostat is in plastic housing with 2 6mm screws low down on front of block)
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I have owned two mk III golfs. A Gti and currently a VR6. When I first purchase the Gti, I had the same problem that you had, ie. temp gauge would not budge from 70 unless I was sitting in traffic. I had absolutley no problems with it, kept it for a further 18 months and then sold it to get the VR6. My VR6 was exactly the same when I bought it, and I have now owned it for 3 years.
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Having the thermostat permanently stuck open will cause the engine to take longer to warm up (increasing fuel consumption and wear), as water will circulate around the radiator from cold.
As BB will attest, this doesn't appear to do any harm. I'd change the thermostat though.
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I think I will change the thermostat too. I wrongly presumed that it was "the norm" after both my mk III did the same thing.
They are £7.20 for the thermostat and another 80p for the housing seal from eurocar parts in case anyone is interested.
I didn't even start this thread, but have managed to sort a problem that I didn't even know I had. Thanks chaps :)
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Perhaps you could let us know if it cures the problem. Thanks
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My 1996 VR6 has a oil temperature display as part of the trip computer etc. Does yours? If so what does this say. I have found that over the last few weeks my temperature guage seems to take much longer to record the normal 90 degrees. I have put this down to the simple fact that it is much colder outside now. The oil temperature seems to pretty much come to the same as the water temperature. I hope that this is normal because as far as I am aware the system is working normally.
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When water temp records 70 degrees computer shows engine oil temp to be between 84-88 degrees. Previously when water temp reached 90 degrees oil temp would be 94-96 degrees. However in the summer on a long journey it reached 106 degrees (bit worrying). With VAG (Milton Keynes) being so unhelpful it would be interesting to know what VW (GmbH) consider normal for these cars. Surely this is the type of data they programme into sensors / ECUs to ensure engines operate within given 'safety' parameters. Garages have adopted the attitude that the thermostat opens before water temp becomes critical so engine wont blow up. Well that's reassuring but doesn't explain what's been going for the last 10000 miles and whether it should be. It will be interesting to know if BB changing his thermostat has any positive effect. If it does then £10 parts is all it will take. If not then who knows!
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Voodoo, have you changed to fully-synth oil recently ? This can have a significant effect on engine temperatures
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VW recommend using quantum gold (fully synthetic oil) for the vr6.
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My car is a VW Golf VR6 (95N). There are 121k miles on the clock and until recently I had it serviced exclusively by VW franchised dealers.
Some months ago I posted a question asking if anyone could explain why my engine?s water temperature consistently refused to reach 90ºC, except in city traffic, and more usually recorded 70º- 80ºC.
Three garages said the system was working within specification ? none did a road test. I knew this response was nonsense, it hadn?t happened before but no one would investigate further. Last week I found the answer and thought I would share it so others of you who might be suffering a similar problem would know where to look.
Of the nine metal vanes usually found on the water pump?s impeller just two sequential vanes were still attached ? the other seven were all lying in the pump?s water bath. The garage had never seen this kind of damage before although a motor industry friend tells me broken vanes on water pumps is quite a common problem generally caused by inadequate levels of rust inhibitor in the water system.
Changing the pump and thermostat has cured the problem and transformed the car?s performance.
It took an independent VW specialist in Essex (John Austin) to diagnose the problem!
Hope my experience is of help to some of you.
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Thanks for the follow-up, very interesting indeed.
I suggest you foward the garage in question to the list of 'Good Garages' on the HJ site itself. Well done lads!
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groups.msn.com/honestjohn - Pictures say a thousand words.....
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