High Water Temp Reading

[firdausasri]

Hi Guys,

First and foremost, my name is Firdaus. I’m driving a 2010 Mk6 Golf R with 128k kms for past 5 years now. So far so good but recently I notice strange reading with regards to water temp that hovering between 93-96 deg c in my BlueDriver app while water gauge stays firmly in the middle. Hope to get some advise on what possibly went wrong?

• On idle, water temp hovers between 94-96 and doesn’t seem to reduce even both fans are running. (strange normally it should be between 87-92). However on highway cruising it dips abit to 92-94 even at high speed of 160kmh. Actual gauge stays in the middle.
• Oil temp (currently on 5w40) hovers between 95-100 deg which this is another issue I’m looking at.
• Radiator fan will keep on working 2-3 minutes after engine switched off (even on most casual drive). Personally I see this as indicator that the temperature is higher than normal.
• No leaks from coolant as fluid remains light pink in color (G13).
• The car has not been overheating else we would have felt from the air coming from the aircond.

At the moment, I’m incline to suspect the thermostat might not fully open but not sure if this is the only one. Do you think there could be other factors?

• - Water pump: replaced at 20k kms
• - Fan: replaced few months back
• - Air bubble in the system but we also changed the coolant expansion tank recently hence shouldn’t be

[Lucas_R]

Could be a faulty thermostat, faulty engine coolant temperature sensor or some air in the coolant system. But its only a few degrees I wouldn't be too concerned.

I remember reading somewhere that the temperature gauge will display 90 degrees and wont move until it sees a jump in temperature so for instance if your coolant is 93 degrees it wont show up on the gauge. Don't quote me on this - i just remember it being discussed several years ago.

I don't really see much of a problem with the oil temperature - my Mk6 GTI used to go between 80-90 degrees oil temperature, and get up to 95 when you were having some fun. The oil temperature is related to how the car is being driven and also the ambient temperature has an effect.

[hoi polloi]

I'm pretty sure VW have put a fudge factor in the gauge to do exactly what you say - keep it pinned at an indicated 90 degrees even though the actual temperature goes a little each side.

Engine coolant temperature - a gauge or a toy? - VW Golf R MK7 Chat - VWROC - VW R Owners Club

Regards

[HaydEn]

All manufacturers soften their temp gauges nowadays.

I have recorded coolant temp as high as 104c and the gauge will still show 90c (MK3/4) - pretty much the same results


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[sambb]

I don't think you have any dramas going on there at all. Like Hayden said water will run high 90's almost all the time. My 1.8T 20V will be on 90 degrees on the gauge and that can be anywhere from 78-98 degrees! You will not see modern direct injected high comp emissions motors running 88 degrees any more. From memory they run split cooling circuits on 6's (could be 7's) where the head water temps are held really high probably for emissions reasons. If you had a thermostat problem and it was stuck open it'd cool right off on the freeway and /or would be very very slow to come up to temp after a cold start. If stuck closed you'd be overheating. The fans running after you stop is normal too and there'll be water pumps running to circulate water through the turbo etc. The oil should be in that range ideally all the time. It sounds to me like everything is doing what its meant to be doing.