VDO oil temp high

[snowbeluga]

Hi all, my oil temp gauge likes to sit at the very maximum constantly, yet my water temp is perfectly normal.

I figured this would be a bad earth or bad sender or something, but thought I would ask anyways.

It's Mk1 storm, so it's a 1.6 Gti, EG engine code.

On a related note, surely if my oil temperature actually was that high, I would have noticed my water temp being overly high as well...? Because other than that it drives fine!

Cheers

Max

[PeteGLi]

With the wire disconnected from the sender, and hanging loose, does the gauge needle stay still when you turn the ignition on (you do not need to start the engine)?
With the wire disconnected from the sender, and earthed, does the gauge needle go straight to hot when you turn the ignition on (you do not need to start the engine)?

[snowbeluga]

Unfortunately I'm not going to be able to take another look until Saturday, so maybe I should have waited till then to ask!

I mean the engine has been running lots with no problems what so ever, seemed great other than the oil temp reading what I assumed to be wrong. What else would I notice if the oil temp was actually that high..?

[mark1gls]

What is the oil temp reading?
How old is the oil and what type and grade of oil are you using?

[go-for-it1]

What Pete said! Disconnect the spade from the oil temp sender on the oil filter, (green/black wire), turn ignition on and gauge should read zero. Touch the spade to earth on the block and the gauge should go to full deflection. If all that works as stated then the gauge is ok. Then connect the spade to the sensor and if it reads full deflection then the sensor needs changing. Make sure you get the correct sensor, it is marked on one of the flats with the range needed, think its 0 - 180 degC. If the gauge is duff it might just be wired in reverse, (Pos to Neg) on the back, the green/black wire goes to the terminal marked G. Hope this helps.
Rob

[snowbeluga]

cheers for the tips guys, will let you know how i get on at the weekend!

[snowbeluga]

Right, got it back now, and it seems that it only flips to 150 when i turn the lights on! (This is assuming 150 is the correct VDO gauge)

However, when running normally without the lights on it seems to be creeping up very slowly constantly, got to about 130 and i turned it off as I didn't want to damage anything....

I have just changed the oil for 15/40 fully synthetic, would the oil filter need to be done as well? Or could it be the oil cooler?

Cheers!

Max

[ianaudia4]

Right, got it back now, and it seems that it only flips to 150 when i turn the lights on! (This is assuming 150 is the correct VDO gauge)

However, when running normally without the lights on it seems to be creeping up very slowly constantly, got to about 130 and i turned it off as I didn't want to damage anything....

I have just changed the oil for 15/40 fully synthetic, would the oil filter need to be done as well? Or could it be the oil cooler?

Cheers!

Max

Why would you change the oil but not the filter, sort of defeats the object mate. Get a proper VW filter from the dealers, they only cost £3.

[snowbeluga]

Right, got it back now, and it seems that it only flips to 150 when i turn the lights on! (This is assuming 150 is the correct VDO gauge)

However, when running normally without the lights on it seems to be creeping up very slowly constantly, got to about 130 and i turned it off as I didn't want to damage anything....

I have just changed the oil for 15/40 fully synthetic, would the oil filter need to be done as well? Or could it be the oil cooler?

Cheers!

Max

Why would you change the oil but not the filter, sort of defeats the object mate. Get a proper VW filter from the dealers, they only cost £3.

Mostly because I am fairly new to mechanics and trying to learn / do as much as i can myself! But yes I will go and pick one up, still not sure if that would be making the temp constantly rise though...?

[snowbeluga]

Changed the oil filter today, as well as removing the oil thermostat and cleaning / freeing up the pin. Did this because I noticed the oil cooler wasn't getting warm, but after I also noticed that both oil cooler hoses were hot though, would assume one 1 would be hot and the other cool.

Doesn't get quite so hot now and after a while seems to settle at about 120 after a blast, was 130 and slowly rising before.

However, I have noticed that both my top and bottom radiator hoses are hot, if not the same temp. Thought the lower hose was meant to be warm, but not hot or cold...?

Also disassembled my wiper motor today and freed it up, yay for finally having wipers!

[Nate]

the coller willbe taking some of the temperature from the oil, but it won't come out cold. feel (carefully!) both hoses of the cooling system radiator when the engine is up to temp - they will both be hot.

so did you just change the oil filter this time, or did you change the oil too? incidentally, 15/40 fully synthetic is not the correct oil for these cars. many people wrongly think that because it is more expensive, it is somehow better. but the engine was not designed to work with fully synthetic oil.

if the oil temp reading changes when you put the lights on, this would suggest that it is an electrical fault. i'd be checking for a bad earth somewhere in the dashboard lighting, i'm guessing this will be earthing back thru the temp gauge

[snowbeluga]

Thanks again for all the tips, think i've had it pretty much sussed now, there was a hairline crack in the expansion tank so that'll be one reason it won't be cooling properly, going to do a coolant flush etc too.

What oil would you recommend then..? I just looked about and saw that most people use 15/40, is 15/40 mineral a better choice than fully synth...?

And yeah, need to look in to these electrics. getting there bit by bit now though :D

[ianaudia4]

Go to a VW dealer and buy Synta Silver, semi synthetic and is what VW recommends. Another good thing it should only cost £20 or so for 5 litres, enough to do a change and have some left over for top ups.

A hairline crack in the expansion tank will not effect things much, GSF sell new ones for about a tenner.

[Nate]

A hairline crack in the expansion tank will not effect things much, GSF sell new ones for about a tenner.

and if it did, it would e from loosing coolant, which would probably make water temp gauge go up, and stop the heater blowing warm air into the cabin.

my money is definitely on an earthing fault. that said, for the price of them i'd replace the expansion tank before the crack opens up and does give you a problem ;)

[snowbeluga]

Ah, see I thought a crack in the expansion tank meant it couldn't build up the proper pressure in the cooling system, thus causing overheating. Plus timing was off, and ignition leads needed renewing so it seems to be running a lot cooler / better now after some playing around, which is nice :)

Definitely got bad earths in there, just a case of getting in to the dash and to the bottom of it all...

Next on to bodywork, but that's a post for another section..!