weird oil pressure behaviour

[bgrunhaus]

Hey  guys!

I have a AAZ 1.9td with weird oil pressure behaviour(as the title states)

look at this video and give me your opinion! http://www.youtube.com/watch?v=mnBFCTRYAuQ

after warmup it idles at 40psi, if i rev it a few times the pressure rises and the start dropping....

turn of the engine, restart and 40psi again! what is going on??

please help me out!

[guy plain]

when is the last time you did a oil/filter change?

[maxfax]

when is the last time you did a oil/filter change?

That, and was it something that started all at once, or gradually?

[bgrunhaus]

i had some issues with th vacuum pump but already fixed that!

after i bit of idling the pressure is now bullet proof! also found out that the previous owner messed with the oil pressure relife valve so im hitting over 100psi@ startup!

thank you guys for the answers!

ill be changing oil tomorrow!


  x 1.000.000

[R.O.R-2.0]

i had some issues with th vacuum pump but already fixed that!

after i bit of idling the pressure is now bullet proof! also found out that the previous owner messed with the oil pressure relife valve so im hitting over 100psi@ startup!

thank you guys for the answers!

ill be changing oil tomorrow!


  x 1.000.000

completely normal..

[ORCoaster]

I hit 100 psi all the time at cold idle start up.  Once it warms it drops to 80, start driving and the standard cruising pressure is 65 to 70.  After a couple of hours on the road it will drop to 40 as I pull into the rest area. 

Was the issue with the vac pump or the seal that goes on it? 

[stewardc]

What has always amazed me is that these engines can see 80 psi cold but only give 15-20 psi warm.

[damac]

curious, what is the oil pressure relief valve and where is it on my 85 jetta td?

[8v-of-fury]

curious, what is the oil pressure relief valve and where is it on my 85 jetta td?

I do believe it is part of the oil filter mount? I could be wrong.

[Mark(The Miser)UK]

curious, what is the oil pressure relief valve and where is it on my 85 jetta td?

I do believe it is part of the oil filter mount? I could be wrong.

I think you'll find it's on the oil pump, and is a piston tube with a crimped end for unservicability purposes, or am I thinking of my old Bedford.

[guy plain]

 a Bedford? now thats showing your age ! lol i have,nt seen one of those in Canada for alot of years (ooops just showed my age as well)

[R.O.R-2.0]

curious, what is the oil pressure relief valve and where is it on my 85 jetta td?

I do believe it is part of the oil filter mount? I could be wrong.

I think you'll find it's on the oil pump, and is a piston tube with a crimped end for unservicability purposes, or am I thinking of my old Bedford.

its crimped shut.

[damac]

Just curious if there is wear on the oil pumps that results in less oil pressure over time.  (assuming of course the pump and vacuum pump are indexed ok and not slipping)

When I got my jetta I cleaned out the pump of rtv and intermediate bearings which I replaced.  I am borderline bently spec which kind of scares me, but I have a manual gage I keep my eye on and pressure increase with the pedal.

I didn't know any better at the time so I just cleaned and reinstalled, but replacing those bearings didn't help oil pressure for me.

I wonder if its possible my 85 jetta td came with the 30mm pump.  If I were to upgrade to 36mm pump anybody got any specific changes in pressures after making the change?

I would just go yank the pan, problem is I sealed it with right stuff last time because it was leaking when I got it.  No leaks now but I have no idea how to get it off

[bgrunhaus]

the issue with the vacuum pump was excesive wear in the rotor.

the pump wasnt installed right onces and the oil pump shaft was pushing the rotor against the pump cap and started grinding the rotor and with time i lost around 1/4" from the rotor!

a friend that has a lathe fixed the pump!

now the vacuum pump drives the oil pump flawlessly!

as for the high pressure i wont worry anymore! thanks for that!

it would be nice installing a bigger pump in the car! i think that hydraulic heads already have large oil pumps!

thank you all for your input!