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Model specific boards => Golf mk2 => Topic started by: tobz. on 20 April 2006, 09:24

Title: Low oil temp reading on mfa
Post by: tobz. on 20 April 2006, 09:24
This morning the oil temp reading on my 16v didn't rise above 74'C even after the 25mile journey to work. I know for a fact that it can't have been running this cold, normally its about 96-100'C, the coolant temp gauge was sitting in the middle as usual.

Is it likely to be a dodgy temp sensor/poor connection to the sensor???
If so is it one of the sensors on the oil cooler? Anyone got a pic to highlight it in?

Cheers
Toby
Title: Re: Low oil temp reading on mfa
Post by: Gambit on 20 April 2006, 12:38
oil temp is on the back of the head on a 16v. wee green wiring running to it. just below the vacuum pipe on the back righthand side of the manifold

74 does seem quite low for a 25mile journey. have you changed the oil or coolant lately?
Title: Re: Low oil temp reading on mfa
Post by: tobz. on 20 April 2006, 13:16
Ah nice one Gambit, I've just been out and cleaned the contacts on both the sensors on the oil cooler but if I remember rightly they are both pressure sensors.
I'll give the one on the head a clean later.

There's no way the 74 reading is correct, I noticed something was up straight away as the initial 50'C reading didn't come up until about 2miles after it normally does.
The oil was changed about 500miles ago and that is still bang on the max mark.
The coolant was changed last summer.
Title: Re: Low oil temp reading on mfa
Post by: 92Mk2Gti on 20 April 2006, 13:19
oil temp is on the back of the head on a 16v. wee green wiring running to it. just below the vacuum pipe on the back righthand side of the manifold

74 does seem quite low for a 25mile journey. have you changed the oil or coolant lately?

On the 8v is it on the top of the oil cooler, the black and green wire?
Title: Re: Low oil temp reading on mfa
Post by: Gambit on 20 April 2006, 14:04
@tobz. - thats a strange one indeed, as you say might just be a dodgy sensor or dirty contacts. the two on the filter are oil pressure sensors

@92Mk2Gti - dunno for certain which wire it is. but oil temp is around there somewhere
Title: Re: Low oil temp reading on mfa
Post by: tobz. on 20 April 2006, 14:17
I'll have a go at that other sensor tonight gambit, tis very strange, last time I drove it on monday the temp was reading the typical 90 odd degrees.
I take it I can remove the sensor without draining the oil as it's fitted in the top end? Don't wanna drain £15 worth of 500 mile old synta silver unless I have to.
Title: Re: Low oil temp reading on mfa
Post by: rubjonny on 20 April 2006, 15:25
yeah let the engine cool right down and you wont loose more than a dribble :)
Title: Re: Low oil temp reading on mfa
Post by: Gambit on 20 April 2006, 15:48
actually it just dawned on me that if the thermostat was stuck open then the car would take a hell of a lot longer to warm up
Title: Re: Low oil temp reading on mfa
Post by: tobz. on 20 April 2006, 16:03
Tis true but my coolant temp gauge was sitting pretty much where it usually does.
I'll stick my heater on full on the way home and see how long it takes for the heat to become unbearable. That'll be a good indicator of thermostat operation.

Oh and one other thought, once it got to 74 it was like it just stopped. I nailed the @rse off it a couple of times and the oil temp didn't even rise momentarily. I think I can therefore conclude that it isn't actually running that cold.
Title: Re: Low oil temp reading on mfa
Post by: Veedubgt18v on 20 April 2006, 17:01
actually it just dawned on me that if the thermostat was stuck open then the car would take a hell of a lot longer to warm up

yeah mine is stuck half open and it rarely gets above 86 and takes a good 20 mins to heat up to that.
Title: Re: Low oil temp reading on mfa
Post by: tobz. on 21 April 2006, 09:36
ok some more info for you all to ponder over.
On the way home last night the temp didn't go above 68.
When I got home I had a play with the sensor that Gambit had told me about.
Cleaned the connection up a bit, checked that with it unplugged I was getting no reading on the mfa.
It didn't make any difference, HOWEVER after about 10minutes of messing about when I gave up the mfa was still reading 68. I'm pretty sure the oil temp on the mfa would drop by a few degrees after 10 minutes of switching the engine off???
It really feels like the sensor has gone dodgy and the resistance doesn't change above 70ish degrees. The reading stops at this point and will read this constantly until the temp drops back below this point.
Does this sound valid???

Oh and where the hell is the thermostat on a valver???
Title: Re: Low oil temp reading on mfa
Post by: Gambit on 21 April 2006, 09:44
if you have power steering its a bit more of an involved job changing the thermostat.

id replace the sender first before attempting the thermostat
Title: Re: Low oil temp reading on mfa
Post by: tobz. on 21 April 2006, 10:58
I had a feeling somebody would say the stat is a b!tch to do, yes I do have pas!!!
Think the sensor has gotta be worth a pop first, guess it will only be about a tenner.