MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: gunnellgti on April 20, 2016, 11:37:21 am

Title: Engine very low temperature
Post by: gunnellgti on April 20, 2016, 11:37:21 am
This may sound like a bit of a stupid question but when just cruising about or on the motorway my engine temp very rarerly gets up to 90' unless im pushing on.
For example i was on the motorway for an hour over the weekend and this is my engine temperature when i came off:
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fah87%2FSamuele_Gunnella%2FIMG_9073_zpsgnzuag5h.jpg&hash=4e1eae4fb02acfa60846f5f69d2f4bc7fa1025e6)
Is this perfectly normal?
Thanks
Title: Re: Engine very low temperature
Post by: Paradox1 on April 20, 2016, 11:46:21 am
Engine temp sensor or thermostat.

not expensive really, may as well change both of them.
Title: Re: Engine very low temperature
Post by: Adam0604 on April 20, 2016, 12:14:55 pm
Yeah that's not normal ... mine is always a solid 90 degrees once engine has warmed up properly.
Title: Re: Engine very low temperature
Post by: Madone on April 20, 2016, 01:03:36 pm
Try sensor first, does the temp rise when sat in traffic ?, if it does its the thermostat, common problem and not a particularly cheap job, it's not ainple to get at.
Title: Re: Engine very low temperature
Post by: puna on April 20, 2016, 01:18:13 pm
I had a similar issue, car not getting above 70 unless in traffic/driving hard. I got both thermostats replaced and this solved the issue (It cost me around £155 to replace, including the parts and replacement fluid)
Title: Re: Engine very low temperature
Post by: pudding on April 20, 2016, 02:03:15 pm
If it's stuck on 50 I'd say it's the sensor but if not, as said, the thermostat is a pain to get at.

Did it on my Edition 30 a few weeks ago and thankfully it's just the one to do.  I did the sensor at the same time.  Whilst you're there and all that.  £40 for the temp sensor tho!

To get at the block mounted stat, you need to remove the alternator, belt tensioner, throttle body pipework and a few other bits and pieces.  Takes about 4 hours DIY, first attempt.  Professionals might have some shortcuts and better tools etc, so might take less time.
Title: Re: Engine very low temperature
Post by: gunnellgti on April 20, 2016, 05:02:38 pm
Thanks for your responses.  :happy2: Its not permanently stuck down low no but after cruising about and not really giving it any throttle it does drop down from 90' fairly quickly. Is it dangerous to not replace these parts?
Title: Re: Engine very low temperature
Post by: Shoduchi on April 20, 2016, 05:42:16 pm
Thanks for your responses.  :happy2: Its not permanently stuck down low no but after cruising about and not really giving it any throttle it does drop down from 90' fairly quickly. Is it dangerous to not replace these parts?
The oil won't be at the right temperature so it won't lube as it should, the ECU will keep trying to warm up the engine so the MPG will be lower and the engine might have less power. Overall it's bad but you can still run the engine until you fix the stat.
Title: Re: Engine very low temperature
Post by: pudding on April 20, 2016, 07:54:52 pm
Yeah it's the mpg that suffers the most as the lambda tables in the ECU will be fuelling against water temp, so will be bunging more fuel in than is necessary.   That can degrade the oil quicker but decent oil can handle it.  Better to fix it sooner rather than later, but summer is OK.  Winter is bad for a stuck open stat.  Over fuelling, crap heaters, sluggish....all of it!
Title: Re: Engine very low temperature
Post by: l2azvan on April 20, 2016, 09:44:42 pm
The right temperature is 90 degree doesn't matter if is summer or winter.
You have to replace the main thermostat, 120 pounds including labour (cheapest). Takes about 2 hours as the position is not quite easy to acces.
Title: Re: Engine very low temperature
Post by: Pesky jones on April 21, 2016, 10:32:13 am
Mine suffered same symptons, would rarely get to 90 unless pushing, sometimes wouldn't even get to seventy after an hour of driving. Main thermostat replaced, now it gets to 90 but does take longer then it should. I believe it should be at 90 within 5 mins easy. Ive got to replace the two inline stats (DSG) to solve this which i'll be doing in the summer.
Title: Re: Engine very low temperature
Post by: Patrick2691 on April 21, 2016, 01:03:01 pm
It should be at 90 within about 10 minutes.  After replacing the main stat mine gets there in that time with some a road driving no queues etc.

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Title: Re: Engine very low temperature
Post by: Pesky jones on April 21, 2016, 01:30:02 pm
ive got a feeling it should get to 90 much quicker then 10 mins...maybe three or four mins
Title: Re: Engine very low temperature
Post by: pudding on April 21, 2016, 03:46:19 pm
Depends on the ambient temp and the driving conditions.   If you drive it hard immediately from cold, that will decrease the warm up time!

I'm surprised the ECU doesn't fault code it.  A lot of other cars throw an "Coolant temp under specified" type code.
Title: Re: Engine very low temperature
Post by: Patrick2691 on April 21, 2016, 08:20:28 pm
Driving normally and keeping below 3k rpm it will take mine a good 10 minutes to get to full temp and then another 5/6 minutes for the oil to catch up. This is going by the actual ECU reading from my Polar FIS. The dash gauge will read 90 when the cars still at 70. Still not safe to hoon it at that point.
Title: Re: Engine very low temperature
Post by: sub39h on April 21, 2016, 10:40:04 pm
Probably the thermostat. I got mine replaced last summer and it fixed the same problem last summer.

Mine was timed with a cambelt/water pump change so I only had to pay for the coolant once but it's fairly cheap if you're not due a change.
Title: Re: Engine very low temperature
Post by: zayd on April 23, 2016, 03:16:50 pm
I just had my thermostat replaced due to eratic temp behaviour on the guage.  Now, after a couple of miles driving it gets to 90 and stays there.  This is how it should behave and anyone telling you otherwise is telling porkies. There is a coolant temp sensor that also does go faulty, but usually the thermostat is the culprit in these cases.