Engine oil temp issue

[captainredeye 0]

Right just been out and had a steady 120c I have not had the car over 3k revs with a reasonable amount of traffic, just got on the duel carriage way and the oil shot Upton 144c pulled over and it instantly went down to 132c did the on off trick read 104c off and 124c when running, could an oil blockage relate hot spots?

Strange that I have changed the sensor and it has got worse, would an auto electrician be a good bet ?

[captainredeye 0]

Just noticed if I display the lower temp with the ignition off and turn the engine over with the lower temp reading being displayed it will continue to read the lower temp, switch of and start the engine with out the oil temp being displayed and it jumps back 18-20c.

[dr_mat 0]

"Jumps back" meaning up or down?

[captainredeye 0]

I meant up which isn't quite how it reads, it will say 104c and jump straight up to 124c

[dr_mat 0]

I have noticed that if you have the oil temp displayed then it is more reluctant to change than if you click off to other data sources too. When waiting for "--" to become "50" for example too many times for it to be a coincidence it's jumped to 50 on a cycle through the screens.

 

So, my best guess is that while it's being displayed the dash is smoothing the data, to stop it jumping around. Which it would! Look at a mk7 golf oil temp reading - it goes up and down by 10-15 degrees depending on where the hottest of the oil is in the system at any given time. (And ours is a modest 1.4t so doesn't really generate anything like the heat of a VR6.)

 

Plus obviously as soon as you stop the engine the oil circulation stops so the sensor sits in a static pool that drains away very slowly.

[captainredeye 0]

Quick update have cleaned all the loom connections and used some wd40 on them which has steadied the temp fluctuations.

Today I have put an Earth on to the temp sensor which has some how left me with the Mfa reading 160c, the temp sender wire was badly corroded so that's going to get replaced next.

[Brucifer 10]

Hi, have you got the MFA to read properly? I am having the same problem of it showing 160 most of the time.

[captainredeye 0]

Sorry just seen this, no i haven't, the water temp has been playing up lately but now seems to hover around 90 again, the oil temp on the other hand has done the same and has been averaging around the 100 mark but occasionally shoots back up to 160, i was driving just last week at 160'c and within a mile it dropped to 118'c and i can't see the oil cooling that quickly, i think its definitely a wiring issue I'm planning on replacing the looms and go from there but will update when i have some news.

[captainredeye 0]

Recently replaced and repaired all the wiring in the engine bay and this seems to of cured the issue of the temp readings, i bought a new front engine loom as the old one was seriously knackered.

[Brucifer 10]

Recently replaced and repaired all the wiring in the engine bay and this seems to of cured the issue of the temp readings, i bought a new front engine loom as the old one was seriously knackered.

 

Good to hear you got that fixed.. Mine still reading 160 all the time... We've got the same '94 Dragon Green!!

[Brucifer 10]

Where did you get the new front engine loom from btw?

[captainredeye 0]

VW heritage sourced it for me from germany, i think i got the last one which was lucky as i held of for sometime before purchasing it.