Oil pressure switch

[FridgeFreezer]

2 hours ago, Anderzander said:

Hmm 🤔. I never drive on road like that - but certain off road routes I do drive off the torque at tick over. On the Td5 with anti stall and on the tdi too - seems I need rethink that.

I don't think it's a big problem on the odd occasion, but as Mr Hobbit states he drives like that all the time over tens of thousands of miles it will add up.

[Anderzander]

I just started mine in the garage and left it running for 20 mins - and I got 50 at cold idle and 25 when it was warm.

[western]

That's pretty good.

[Mo Murphy]

Presumably thicker oil would help with oil pressure ?

 

Mo

[Anderzander]

Or more of it 😱

[Sigi_H]

I am not a specialist in plain bearings. But as far as I understand it, the pressure of oil is responsible for the needed oil flow through the bearing, but this is minimal. The lubricating pressure IN the bearing is produced by the bearing itself (with a lubricating wedge produced by the turning shaft) and is very very high. A lot higher than the pump can provide.

That means in my eyes, you can live with a low oil pressure, as long as you make save, that the pressure (inside) the bearing is high enough to start it. To start it means, give the engine a small pulse of revs when idling before you put load on it . Don't let it pull away with heavy load from idle with low oil pressure. Give it a small push without gear just to raise the pressure and then pull.

Viscosity of the oil does not need to be raised because it depends a lot more on operating conditions of the vehicle. It is really bad, if you raised the viscosity and have a good pressure when hot, but when you fire up the engine in the morning it is not lubricated at all, because the oil is to thick.

Specialists say it is best to have a very short time until the engine is "oiled through". Thicker oil lifts the pressure but will make this time a lot longer.

This is how I understand it.

 

Edited June 1, 2020 by Sigi_H

[Bowie69]

19 minutes ago, Sigi_H said:

when you fire up the engine in the morning it is not lubricated at all, because the oil is to thick

Agree with the rest of what you say, but in this quoted case, this is where wide range multigrade oils come in.

I think 200TDI are recommended 10w40 for our (UK) climate, as long as you don't raise the smaller number, the thickness of the oil is not changed when cold.

20w50 was a staple of old, which still left a lot of slow cranking cars on cold mornings, nowadays you can get a much wider range, Mobil 1 years ago being the first, I think, to go to a '0' oil with 0w30. But more suitable here if you did want to raise the thickness when cold, you can get 10w50, 10w60, or 5w40, 5w50, 5w60 quite easily now.

Not saying it is a solution for this case, but some very high mileage engines do appreciate a bit of extra cushion in the bearings!

 

 

[Sigi_H]

13 minutes ago, Bowie69 said:

Agree with the rest of what you say, but in this quoted case, this is where wide range multigrade oils come in.

I think 200TDI are recommended 10w40 for our (UK) climate, as long as you don't raise the smaller number, the thickness of the oil is not changed when cold.

20w50 was a staple of old, which still left a lot of slow cranking cars on cold mornings, nowadays you can get a much wider range, Mobil 1 years ago being the first, I think, to go to a '0' oil with 0w30. But more suitable here if you did want to raise the thickness when cold, you can get 10w50, 10w60, or 5w40, 5w50, 5w60 quite easily now.

Not saying it is a solution for this case, but some very high mileage engines do appreciate a bit of extra cushion in the bearings!

 

 

you are right, but even with multigrade oils the lubricating times when cold start are a bit longer. This is the reason, why the first number on multigrade oils becomes lower. They want to keep this times low, as they count in seconds.

[Ex Member]

On 5/31/2020 at 4:11 AM, western said:

oil temp 65/70 degree C

To properly check hot oil pressure, you need to get the oil to maximum temperature, which is around 95 to 100 C.  You need a hard drive for 15 to 30 minutes.  Then check idle oil pressure.  There is a huge difference in viscosity between 65 and 95 C. A typical oil's viscosity is 6 times higher at 40 C versus 100.

[Nonimouse]

1 hour ago, Red90 said:

To properly check hot oil pressure, you need to get the oil to maximum temperature, which is around 95 to 100 C.  You need a hard drive for 15 to 30 minutes.  Then check idle oil pressure.  There is a huge difference in viscosity between 65 and 95 C. A typical oil's viscosity is 6 times higher at 40 C versus 100.

Really does make a huge difference. I'm working on pressures at hot, not warm, using tell-tales on the oil cooler outlet pipe and the turbo oil drain pipe

[Snagger]

Likewise.  My pressures are for oil around 90oC.

[Nonimouse]

I've lost any motivation to continue. I'm seriously thinking of breaking or selling the vehicle and buying a nice reliable Japanese vehicle. Towing 3.5 tonnes is no longer essential, as I can use a tractor. The chipper is only 1.75 tonnes and tows easy.  I've got access to a 2.7 tonne trailer (with Hiab....

[Anderzander]

Oh no !   We’ve been there ...!

Take a break. Worst case isn’t the end of the world - but it’s clearly become a downer, so take some time away.

[Bowie69]

You thought about shimming the relief valve spring?

Wouldn't need much.

[FridgeFreezer]

Freelander!

[Maverik]

200tdi (lots and lots of miles on it)  10w40 oil - Running at Oil temp 106degC - 3000rpm (65mph) Oil pressure 32psi - idle oil pressure @ said temp 12-15psi.

I find it fascinating watching the pressure value change with oil Temp.

[Snagger]

It might be worth a call to Turner and asking them what pressures are normal at high temperature.  Quite a few of us are getting similar results, so perhaps the turbo saps too much off a pump designed not to have one and the pressure drops that little bit off the book figures that LR never updated from the 12J?

[Nonimouse]

Some long chats with a couple of friends last night. Back feeling motivated.

I'm going to ring Richard today

I'm going to finish fitting the Electric Gauge and remove the test gauge.

Then I'm just going to drive it.

Collection of my spare engine has been planned - and what it will need to be ready to fit. When that's done it will be bagged and put n the engine racks in the barn, ready.

I have too much time and effort (let alone money) invested in what is a strong, tidy vehicle

[Mo Murphy]

Good decision Lovvers 👍

Mo

[Ex Member]

21 hours ago, Maverik said:

200tdi (lots and lots of miles on it)  10w40 oil - Running at Oil temp 106degC - 3000rpm (65mph) Oil pressure 32psi - idle oil pressure @ said temp 12-15psi.

I find it fascinating watching the pressure value change with oil Temp.

Pretty much the same as mine.

[Mo Murphy]

A question that may lead to a brief divergence of topic.

I've just been given a 20L can of 5w30 engine oil from work (for topping up a vehicle we no longer have on the fleet).

What are the panels thoughts on using it in a 200 Tdi ?

Mo

[Snagger]

You’d get away with blending it 1:4 with 10w40 in winter, I’d think, but otherwise I think it’s too thin.

[Retroanaconda]

Manual suggests okay from -30 to 30 degrees. I’d run it in the winter but not the rest of the year. Assuming it’s the right spec - the Tdi takes a nice basic oil.

Blending as above would be a good way to use it up. 

[Ex Member]

I personally would not use a xW30 oil seeing how low is the hot oil pressure.  This is solely set by the hot viscosity.  The 30 number is set by the viscosity at 100 C.  40 is a range above 30.

[Sigi_H]

Just use it. A 5W30 in these days is way better than the mentioned 5W30 by the manual 30 years ago.