Using a synthetic on a high mileage oil burner?

[JohnSaints]

Hi all.

Is it true that if you change from a 10w40 synthetic blend to a 5w40 synthetic you will burn even more oil (considering that the engine already burns oil with a 10w40)?

I'd like to try 5w40 synthetic because:
1-It's better for the engine (it's in the manual as one of the possible grades to use)
2-It can withstand a longer OCI.
3-I will experience low temperatures in the winter, so the lower flow resistance will be awesome.

I've read that the 5 grade means it's a thinner oil but I've also read that that is meaningless and the grade only means how well it flows at cold.

Ive also read that a synthetic will clean up the engine so well that it can damage the oil pump with all the debris it gets.

I wouldn't mind the same oil burn as now, but not higher.

The engine in question is 110.000 miles and, as far as I know, has always used 10w40 synth blend. It is currently burning around 2.5 liters in 6000 miles. First oil change was worst, as it burned aroung 4 liters in 600 miles.
Before I bought it, the car was almost non used, as it was only driven for aroung 8k miles in 4 years.

Here are the specs of the oil I've used in the last OCI (BP VISCO 5000 10W40):
10W-40
Relative density at 15ºC ASTM D4052 g/ml 0,873
Kinematic viscosity at 100ºC ASTM D445 mm²/s 14,2
Kinematic viscosity at 40ºC ASTM D445 mm²/s 95,0
viscosity, CCS -25ºC(10W)ASTM D5293 cP 5880
Calcium ASTM D4951 % weight 0.226
Phosphorus ASTM D4951 % weight 0.093
Zinc ASTM D4951 % weight 0.103
Viscosity index ASTM D2270 - 154
Fusion point, v.f. ASTM D93 °C 189
Sulfatated ash ASTM D874 % weight 1,05
Total Alcalinity, TBN ASTM D2896 mg KOH/g 8,0
Freeze point ASTM D97 °C -36

 

[qdeezie]

Do they have synthetic high mileage motor oils in Portugal?

 

[JohnSaints]

Originally Posted By: qdeezie
Do they have synthetic high mileage motor oils in Portugal?


I have never seen any for sale. I'd use any synthetic 10w40 or synthetic high mileage oil I could find from a reputable brand... But I think they're almost impossible to find here...

 

[JohnSaints]

EDIT TO MY POST:

The engine in question is 110.000 miles and, as far as I know, has always used 10w40 synth blend. It is currently burning around 2.5 liters in 6000 miles. First oil change was worst, as it burned around 4 liters in 6000 miles.

 

[eljefino]

I'd pull the valve cover and check for sludge. If there's just varnish on stuff I'd go ahead with the change to 5w40. I don't know much about the quality of syn-blend where you live.

 

[JohnSaints]

Synth blend quality here is the same as in the rest of western Europe.

My current synth blend oil has these specs:
ACEA A3/B3; API SL/CF; VW 505 00; MB-Approval 229.1

Is it easy to pull the valve cover? Can it be screwed back on afterwards with no problem or extra job to do?

Removing the oil filler cap exposes a bit of the engine and it's all shiny, no sludge at all. Is this an indicator of anything?

Are the rest of the "changing to synth" fears on my first post unsubstantiated?

 

[JHZR2]

I'd move to a 10w-40 HM oil which is syn (M1 for example), which will have some of the factors blended in which are designed to support high mileage engines!

 

[JohnSaints]

Originally Posted By: JHZR2
I'd move to a 10w-40 HM oil which is syn (M1 for example), which will have some of the factors blended in which are designed to support high mileage engines!


I'd use it in a heart beat if it was available... Unfortunately I don't think I've ever seen a 10w40 synthetic or 10w40 high mileage oil here or in a few other european countries (I do know a few exist, like a specific motul oil, but It's extremely expensive).

 

[Warstud]

Try some Castrol Edge...it's a synthetic that has reduced the consumption in my truck quite a bit.

 

[Patman]

If you can find Pennzoil Ultra 5w40 over there, give that a try, it helped reduce the consumption in my Corvette (the 5w30 version of Ultra anyhow) It was burning one quart every 5500 miles before, but on my last interval it was down to only 1/2 of a quart in 6600 miles!

 

[xantonin]

I think a synthetic oil would be a good thing to try in an oil burner.

Usually synthetics will have a much higher flash point, and are less volatile which may help prevent it from evaporating..

But it might not make a difference if the valves are leaking into the cylinder and the oil is being burnt there... On the other hand, the right synthetic oil may treat your seals better and leak less...

 

[JohnSaints]

Originally Posted By: xantonin
I think a synthetic oil would be a good thing to try in an oil burner.

Usually synthetics will have a much higher flash point, and are less volatile which may help prevent it from evaporating..

But it might not make a difference if the valves are leaking into the cylinder and the oil is being burnt there... On the other hand, the right synthetic oil may treat your seals better and leak less...


Really? I always read about synthetic cleaning everything up inside and maybe making the burn worse permanently...

In case I try a synthetic it will always be from a reputable brand, like BP, Shell, Total, Mobil, Castrol and the likes.

 

[mechtech2]

Always go for the lowest first number for the best cold weather performance.

Around here [this forum] many say that "No oil is too thin at start up.]. This is very much true.


For cleaning? Do you really need it? Modern oils are all very good .

Leaks? Who knows? It may or may not start seeping here and there.

Burning? You have to try and see. No one can predict what will happen. Even similar oils can act very differently in particular engines. In general, thicker oils burn less.
But give any new at least 500 miles to stabilize and then pass judgement.