Technical query for tonight - I noticed today that my oil pressure seemed to be tad lower than normal. So I checked the owner's manual and the workshop manual which are a little contradictory (there's a surprise!).

 

Having converted to proper units (i.e. psi):

- the owner's manual says "normal" is between 9psi and 85psi

- the workshop manual says (when warm and without load) idle is 11psi and 3,000 revs is between 51 and 65psi

 

Today I was getting (on a standard OEM gauge and after being well warmed up on the motorway) 8 or 9 psi at the low end and maybe 30 to 40 psi while trundling (60mph in top, hardly any throttle).

 

And the needle seems to wander about much more than it used to (it used to be fairly well related to engine revs but now its much more vague).

 

What would you be happy with on an unmodified TT engine at around 90,000 miles?

 

If you think my oil pressure is on the low side, what would you check first?

 

TIA - Gio

I think it is on the low side. I have never seen the pressure drop below 30psi. It usually settles are 30psi at idle when warmed up and like the online manual says is about 65 at 3000rpm.

 

 

Stuart

as a rule of thumb, most engines are 2 bar min at 2000rpm when hot.

 

it really is no good checking it on the stock gauge tho. :)

I think my stock guage works perfect on this zed, the one on my old zed harly worked at all.

 

Mine is in weird jap scale but if you start it from cold it goes to half way on tick over and upto 3/4 when a little load is applied, i drive like a girl until its warm so ive never seen it go over 3/4.

 

Once it is warm, on tick over its about the quarter mark, going up to the half way point and a bit beyond when some wellly is applied.

 

Anyone know a conversion ratio from the j spec to uk??

Use this conversion program to work it out.

"Mine is in weird jap scale but if you start it from cold it goes to half way on tick over and upto 3/4 when a little load is applied, i drive like a girl until its warm so ive never seen it go over 3/4 "

 

 

 

Mine is the same as this, did worry me for a while but after checking everything I put it down to being " normal " for the stock guage

Hi Gio

 

When fully warmed up, mine stays at just under the 30 psi at 1000rpm.

 

At 60-70mph (2-2500rpm) it is about half way between 30 and 60psi.

 

At 80-90 (3000rpm) it is dead on 60psi.

 

As the pressure is also consistent with engine effort, not just engine speed, 30-40 psi sounds reasonable for 50-60mph (at 1500-2000rpm) since the engine is barely working. The forward motion of the car is probably providing more effort than the engine.

 

My oil pressure was quite erratic recently, especially at idle and low speeds when hot. I replaced the sender unit and that sorted the problem.

 

If you are worried, get your garage to set up a mechanical gauge to check it accurately. You may get a pleasant surprise!;)

 

HTH

 

Richard:)

Thanks gents - v.helpful as usual. I checked levels (again!) today and did a stone cold pressure check - which was around 90psi so that seems fine. Just off for a drive to see what happens.

 

Hopefully it's a dodgy sender as these do seem to go. So will get someone to do the mechanical check as suggested.

 

In case anyone else still uses the OEM gauge, thought this might be helpful.

kg/cm2 > psi

1 = 14

2 = 28

3 = 42

4 = 57

5 = 71

6 = 85

7 = 99

8 = 114

 

HTH - Gio

90PSI is about right when cold. There is an oil pressure release valve which opens up at 90PSI.

 

 

If it goes over it tends to mean this valve is starting to fail or is slighly blocked.

Okey-dokey, just been for a shortish drive and found out that for the first 10 miles / 20 minutes or so, the gauge behaves as expected. Lots of oil pressure and then as it warms up (water temp gauge about horizontal) the oil pressure sits around 50 - 60 psi as it should (at around 3000 rpm in every gear).

 

Then it suddenly plummets to almost nothing and then the needle moves around in a vague manner between almost nothing and 30-ish psi.

 

Does this sound like what happens when the sender is on the way out (failing when hot?) or is there another more serious problem I should look for when we are doing the test with a mechanical gauge?

 

TIA - Gio

That is typical sender failure. Mine acually worked over 40psi., under that just dropped to the 0.

Hi Gio,

 

Was gonna say the sender is usually at fault and not the bearings!

 

Replace the sender, but these are only meant to last a few years before failing!

 

I would say don't worry about oil pressure unless you can hear your bearings knocking!:shock:

 

It is not a common fault on zeds!