Idle oil pressure.

[inman999]

The oil pressure in my Mk1 1.8 seems a little low to me. Once warm it sits around 1 bar and at a constant 3000 revs its 2 bar. The oil is changed regularly using semi synthetic 5W/40. Engine has 110k Km on it and seems to run fine other than some HLA noise.

What pressures are you seeing?

[FrancisMX5]

On that mileage I'd probably switch to a thicker 10w40.

Mines on around 90k and I use 10w40. Your pressures should be higher than that really.

No HLA noise here either.

Edited by FrancisMX5 on Monday 4th October 12:26

[JFReturns]

Mine depends how many revs im doing! I Don't pay a huge amount of attention to it really

[NeoVR]

What does that mean on an import?.

On my 94 1.8 - it reads around 2KG/CM at idle when up to temp (equiv to 1/3 on the gauge and slighly lower when red-hot) and 4KG/CM when over 3grand(2/3 on the gaugue) and much higher when the oil is cold.
I use 10/40 semi-synth..

[Mazdamender]

inman999 said:

The oil pressure in my Mk1 1.8 seems a little low to me. Once warm it sits around 1 bar and at a constant 3000 revs its 2 bar. The oil is changed regularly using semi synthetic 5W/40. Engine has 110k Km on it and seems to run fine other than some HLA noise.

What pressures are you seeing?

Do you have an after market dail set on?

[inman999]

Mazdamender said:

inman999 said:

The oil pressure in my Mk1 1.8 seems a little low to me. Once warm it sits around 1 bar and at a constant 3000 revs its 2 bar. The oil is changed regularly using semi synthetic 5W/40. Engine has 110k Km on it and seems to run fine other than some HLA noise.

What pressures are you seeing?

Do you have an after market dail set on?

Nope its standard dials on a Eunos import. The scale is in Kg/cm2 , which I believe is basically the same as bar i.e. 2 Kg/cm2 is equal to 2 bar, I may be wrong.

It seems my oil pressure is definitely down.

5W/40 is the same viscosity as 10W/40 its just that the 5(W)inter is thinner at cold to help cold starting but is exactly the same at operating temps.

Maybe its time for a new oil pump.

[skinny]

how old is it and what oil is it? part-synth needs a fair bit of viscosity index improvers (polymers) to hit the 40 grade and these shear down over time making the hot viscosity thinner than with a new oil, you might find an old part-synth 5W-40 is closer to a 10W-30.

fully synths need less VII and stay in grade better.

[inman999]

skinny said:

how old is it and what oil is it? part-synth needs a fair bit of viscosity index improvers (polymers) to hit the 40 grade and these shear down over time making the hot viscosity thinner than with a new oil, you might find an old part-synth 5W-40 is closer to a 10W-30.

fully synths need less VII and stay in grade better.

I change every 7500Km and use new filter and flush everythime. Oil is approximately 5 months old and 5000Km. I guess it could have sheared down as I give it a fair bit of stick.

I'm leaning more towards a worn bottom end as I can exclude some of the more common causes I think. I may do an oil change this week to fully synth.

Does anyone know how good Halfords own brand oil is, I assume its made by one of the large manufacturers.

[anonymous-user]

These oil pressures sound fine to me - I've had 2 Eunos Roadsters (both 1992 1.6s if that makes a difference) - they both sat at about 1 on the dial when at hot idle, rising to between 2 and 4 when being driven dep. upon revs.

One was an immaculate car with the original engine and about 80k on it and 10W40 oil, the other was a snotter with a recon engine with about 3000kms on it using fully-synth 5W40, and both behaved the same.

The only difference was that when being driven from stone cold the car with 80k on it would push the dial right to the max (is that 6?, i can't remember), whereas the other car displays about 5.

Interesting link here on the inaccuracies of the older style oil pressure gauge:
http://www.miata.net/garage/opg_diagnostics/index....

Edited by anonymous-user on Tuesday 5th October 20:04

[franv8]

Mine's similar to JimSuperSix, 1.6 Eunos. Although it stays at 2 at idle when hot, and often banged over at 6 when cold (at speed). It does seem that the sender isn't the most accurate though, I think it often adds 2 bar when hot at running speeds.