Stupidly hot oil, reasons?

[p0l1wrath 10]

The Corrado reached really high oil temps the other day, I'm surprised its still running, what are possible causes of high oil temps?

 

Things to consider;

Recent oil temp sensor

Recent oil and filter change

Recent mocal cooler removal, back to exchanger

Usually sits around 108º-116º (same temps before mocal removal)

Hit high temps after a VERY short heavy foot session (about 15 seconds)

Sometimes seems to behave and stay around 108º-116º but then sometimes will go higher, if i have a heavy foot , quite intermittent

 

Do the pumps brake?

 

Cheers

[g0ldf1ng3r 15]

hi m8

a little more detail would help here......what kind of temps are you seeing & how does this compare to after the recent parts you have fitted/removed

 

my spurious oil temp readings on the dash was found to be due to corrosion on the connector which plugged into the new oil temp sensor - i had a reading of 150 at one point & went into panic mode lol

the new oil temp sensor was fitted during work at stealth & they put a fresh connector on there & normal oil temp activity was resumed

oddly though i had asked them to check if there was any difference between the temp at the oil sensor & the reading on the dash & their laser tool showed that the dash reading was 6 degrees higher than at the sensor itself

 

Also regarding oil pumps, yes they can cause issues - if you can then check your oil pressure when the engine is cold, IIRC it should be at around 1 to 1.5 bar

Again when my VR was at stealth it was found that my sump oil pump was not well & it was resulting in way too high a pressure - about 9 bar on the pic vince sent me - & had caused it to force a leak out of the new head gasket

Edited May 7, 2014 by g0ldf1ng3r

[p0l1wrath 10]

I seen 148º yesterday after a little blip on the way home from work, so yeh i also went into panic mode!

No changes to normal running temps after parts change, but just doesn't seem to be able to handle me giving it some, when i say some i mean like upto 80 in third, on the autobahns on the way home from work of course

[g0ldf1ng3r 15]

Definitely worth checking the connector onto the sensor and also the wire for any breaks etc as if the voltage along the wire is effected it will throw out the dash readings

Im not sure what laser tool vince used to check the temp at the sensor but it would be a sanity check to confirm what the actual temp is (rather than rely on the dash reading)

[MarkB 10]

I have this problem with mine, I replaced the original temp sender just because it had a slight leak with a known good quality make and the reading went up by about 20-30deg.

I just assumed that its calibration is a little out as nothing else was changed.

[fla 9]

If you were getting 120C+ oil temps, when you open the bonnet you would really feel the heat off the engine. As above, check the sensor, perhaps remove the old spade connector and refit a new one.

[Kevin Bacon 5]

Agreed. There is no way the oil is actually ~150 degrees. Not even my VR6 turbo got the oil that hot.

 

This is why VW dumbed down the gauges in later cars. No oil temp, no oil pressure gauge and water temp calibrated to always sit in the middle. If the info isn't there to panic about in the first place, there's no reason to panic :)

[J.C 10]

I've looked into this issue quite a bit,

my obsrvation consist of sump plug sensor,

standard Sensor in 24v oil filter housing,

Long sensor in 24v oil filter housing,

Thermocouple down the dipstick tube,

I too was reading high 140+ last year,

I've come to the conclusion that the cause for the high reading is heatsoak from the engine block,

I plotted MFA reading vs thermocouple reading and when MFA read 110, thermocouple was 98,

I then put the longer sensor in (longer because the 24v doesnt have an oil temp sensor and you use the deaper threaded oil pressure port) so to get the sensor in the oil flow, MFA read 104, thermocouple 98

senders are NTC (negative temp. coefficient) meaning the higher the temp, the lower the resistance (higher resistance = lower temp), it's a bit puzzling why a bad (high resistance) connection would give higher temp. readings,

I have thought of putting a resistor (prob 15 ohms) in series to callibrate the sender/MFA to the readings of the thermocouple, but prob wont as all I do is look at the MFA temp and minus 5 or 6 degrees, in the summer if I get high readings I'll look into it further.

Also all sensors were checked for correct values in saucepan of boiling water

check link for good info

http://www.clubgti.com/showthread.php?228287-THE-VW-Temperature-sender-values-range-and-colours-mix-and-match-guide

Edited May 9, 2014 by J.C

[Kevin Bacon 5]

I think some of it is down to the schittness of the original sensor. The brass body just heatsoaks and skews the reading as you say. What's needed is a proper exposed thermocouple sensor as you say.

 

The intake sensor of the VR6 does the same. It heat soaks to way over 70 deg C when parked up after a run. You get back in the car for a run and get massively retarded advance but the actual air temp coming in is much less than 70 deg. And the sensor response is like 10 degs drop every minute. Rubbish!!

 

Still, it is an old car with old technology.

[J.C 10]

Definatly one of the cheapest and easiest mod to put an IAT sensor from the 1.8T (I think) into the airbox below the MAF,

I look at the MFA temp reading as more of an engine block temp.

Maybe this would give accurate readings but would be hard to change the thermocouples voltage output to a resistive value the MFA needs

http://www.aim-sportline.com/download/doc/eng/sensors/Datasheet_H2O_M10_eng_101.pdf