Oil Pressure Drops As Temperature Increases?

[Ben 0]

Hi guy and gals,

I've had my 1.6 gti for a few days now but I'm getting slightly concerned about the oil pressure when hot. When I first start the car the oil pressure gauge goes to the middle which I hear is about right? Once the engine gets up to temperature, with the oil temperature gauge up to around half, the oil pressure starts to drop all the way down to the red mark.

The warning light hasn't come on yet but I am a bit worried.

 

Is it possible that it could be something simple like the wrong oil being used or a dodgy gauge sender? or is it something worse?

 

Cheers for any advice.

 

(P.S I tried to search but its down at the moment)

Edited October 14, 2007 by Ben

[cybernck 402 1 Cars]

that's pretty normal... when the engine's cold, the oil pressure is about 6 bars

(shame you don't get value written on the gauges in the UK ) and drops

down to below 2 when the oil is up to temp (logical, as the oil gets thinner).

 

still, it should rise a little when you rev the engine but a dodgy sender or a gauge

would be a lot more obvious . that's why the switch for the STOP light is seperate

and if it doesn't light up it's probably ok.

 

hope this helps.

[Ben 0]

Cheers for the reply,

 

I've seen pictures of the gauge with the numbers on it and from it i reckon my oil pressure is 3.5-4 bar when cold and drops to as low as 1 bar when hot.

Im going to change the oil and filter during the week, any suggestions to what oil? Do i need slightly thicker than normal to try and help build the pressure a little?

 

Also is it worth me changing the sender and if so which is the right part?:

05EM050 Oil gauge transmitter (larger on right) OE

or

06EM049 Oil pressure transmitter (smaller on left)

 

Cheers everyone

[pugman211 0]

oil pressure sender is the larger looking one on the right, and they cost about £55 from Pug!! (i know!!! lol) You could try thicker oil but best to stick with semi synthetic 10w40.

 

The smaller one on the left is the pressure warning light switch - basically, the STOP light in the car.

[Ben 0]

Any suggested brands of oil? Guessing I dont want halfords own or such like.

 

Ben

[pugman211 0]

Think most oils are pretty much the same, depending on how you drive etc. Some people will say Gastrol magnatec, some people will say Mobil 1.

 

The choice is really down to you - either of the above will do though.

[Ethos 0]

Ours does that, 2 bars up when just turned on... when warm its normally just below one but goes just over two when rev'd.

[Miles 331 1 Cars]

The guage is more show than anything else, try different sender's and guages and most will give a different reading.

But as said when the oil get's hot even on new engine's the pressure goes down, Any Semi Syth oil will do just fine, Doesn;t need to be a top brand or anything just get a OE oil filter which are cheaper than say Halford's

[Ben 0]

Cheers everyone, its put my mind at rest a bit. 205's are completely new to me and I've not even had mine a week so i didnt want it blowing up on me!

I've now got semi synthetic 10w40, OE oil filter and sump plug washer on the way.

 

Ben

[oilman 7]

Yes, sounds to me like the oil is tired, as it gets tired it looses its viscosity when hot, thus thinning down in effect.

 

Replace it with a good 10w-40 semi or 5w-40 full synthetic and all should be good.

 

Cheers

 

Guy.

[Simes 248 2 Cars]

As Miles says the guage isn't that accurate and from what you're describing it sounds quite normal. - you'll know when it goes wrong when the red light and stop light comes on.

 

Enjoy!

[Ben 0]

Cheers for the advice everyone

 

Yes, sounds to me like the oil is tired, as it gets tired it looses its viscosity when hot, thus thinning down in effect.

 

Replace it with a good 10w-40 semi or 5w-40 full synthetic and all should be good.

 

Cheers

 

Guy.

 

I've got 8 litres of semi-synth silkolene xtr 10w/40 sat here courtesy of your ebay shop, just waiting on a filter now.

 

Cheers

Ben

[wardy18 33 1 Cars]

sorry to barge in on the topic but whilst ur talkin about oils, ive always run Magnetec 15w 40 just to be safe as i know they are gettin old engines now, would i be better off runnin 10w 40, the engine has only done 58k miles and so is pretty low for its age, it does give a little blue smoke now and then!?

 

also what oil would you recommend for a freshly built engine that isnt for road use but solely for hillclimb use?!

 

thanx and sorry again to jump in

[CaptainK 11]

Guy.

http://www.opieoils.co.uk

*waves at Guy*

Yup, its the same CaptainK from FTOOC.

 

I've got your 10w50 Silkolene oil (which you know I love ) in my Pug, and has had other oils in it in the past. Whether its new or old, my oil pressure gauge does the same thing :- about middle when cold and edging on "red light" when up to temperature. I've been told by this club that the gauges aren't too great anyways, so I'm not too worried. Especially as its been like that for 6-7 years that I've owned it.

[Simes 248 2 Cars]

sorry to barge in on the topic but whilst ur talkin about oils, ive always run Magnetec 15w 40 just to be safe as i know they are gettin old engines now, would i be better off runnin 10w 40, the engine has only done 58k miles and so is pretty low for its age, it does give a little blue smoke now and then!?

 

also what oil would you recommend for a freshly built engine that isnt for road use but solely for hillclimb use?!

 

thanx and sorry again to jump in

 

58k is quite new these days, mine was blowing smoke at 66k - got the valve stem seals replaced which sorted it. 10/40 or 15/40 ok.

[wardy18 33 1 Cars]

58k is quite new these days, mine was blowing smoke at 66k - got the valve stem seals replaced which sorted it. 10/40 or 15/40 ok.

 

are the valve stem seals a big job, ie removing the head, im not sure even which part this is, will have a look around

 

thanx for the info

[Pob 1]

are the valve stem seals a big job, ie removing the head, im not sure even which part this is, will have a look around

 

thanx for the info

 

I had dodgy oil pressure readings, I got a pressure sender from my local motor factors... Part Intermotor 53800 £20 inc Vat, works perfectly now

 

Dan

[pug_ham 245 3 Cars]

Fuchs XTR 10w40 semi synthetic, £10.70 +vat from gsf.

 

Graham.