Mix Castrol Edge Syntec 5w40 with TWS 10w60?

[Brit33]

Can I mix Edge Syntec 5w40 with TWS 10w60?

Been using TWS 10w60 for a while, been very happy with it, but I suspect it's beginning to shear already.

Have some Motul 15w50(factory spec'd grade, well 10w50 is what they say) 300v but I'd rather stick with one brand of oil hence Castrol.

Have flat tappets that need a good zddp. I can't get syntec 5w50 hence the mixing.

Thanks

 

[skyship]

You are right to stick with one brand, but it is a good idea to do a UOA to find out what the result is in terms of both engine wear and how much Zinc is in the oil.

 

[supercity]

Why not add more 10w60?

I've seen a UOA where Castrol Edge 10w60 sheard from 24 to 19 cst in only 2000km in an Alfa JTS engine.

 

[Brit33]

Originally Posted By: skyship
You are right to stick with one brand, but it is a good idea to do a UOA to find out what the result is in terms of both engine wear and how much Zinc is in the oil.


I live in a world where testing is unavailable I'm afraid.

 

[Brit33]

Originally Posted By: supercity
Why not add more 10w60?

I've seen a UOA where Castrol Edge 10w60 sheard from 24 to 19 cst in only 2000km in an Alfa JTS engine.


ahh I've done 3500 kms and noticed a small drop in pressure. I push my high revving alfa pretty hard.

So you recommend just sticking with the 10w60 and doing a change instead of mixing?
If I need to change it every 3500 kms it gets a bit pricey.

or maybe go back to the Motul 300v? (same HTHS)

 

[Doug Hillary]

Hi,
Brit33 - Be wary of the comments on shearing here on BITOG. Some comments are less than accurate and many don't allow for the formulations enabling a reasonable permanent shear window. As well, fuel dilution must be factored in

Trended UOAs will tell you a moving story

I have used Castrol's 10W-60 over several deacdes and in many engine families (bikes, cars and diesel trucks) and significant permanent shear was never an issue

 

[Brit33]

I see 5w40 has a hths of 2.9. pretty low.

i have recently increased my main jet size due to ethanol fuel use and previous lean condition problems.
maybe its just this jetting change.

how do the double ester oils like 300v handle higher fuel dilutions?

 

[Gabe]

Originally Posted By: Doug Hillary
Trended UOAs will tell you a moving story


Only on BITOG will you see somebody describe a series of UOA as a moving story....

 

[KCJeep]

Originally Posted By: Brit33
I see 5w40 has a hths of 2.9. pretty low.



Castrol only posts the minimum spec required for some dumb reason, the actual HTHS on Castrol Edge 5w40 looks to be about 3.6.

 

[Brule]

BMW trusted the Castrol TWS 10w60 in my '06 M Coupe for 24000 km. If you're concerned about it shearing, then it's probably become a 50 weight...but you're considering 5w40...one more grade lower. I'd stay with just TWS for the full Alfa recommended OCI; if it's been a good fit for this engine don't be concerned about a small drop in pressure. If this drop in pressure continues, then of course go back to the Motul 300v.

 

[supercity]

Originally Posted By: Brit33
Originally Posted By: supercity
Why not add more 10w60?

I've seen a UOA where Castrol Edge 10w60 sheard from 24 to 19 cst in only 2000km in an Alfa JTS engine.


ahh I've done 3500 kms and noticed a small drop in pressure. I push my high revving alfa pretty hard.

So you recommend just sticking with the 10w60 and doing a change instead of mixing?
If I need to change it every 3500 kms it gets a bit pricey.

or maybe go back to the Motul 300v? (same HTHS)


I just think 300v is a bit of an overkill. A cheaper oil with the same HTHS should be fine. A decent 20w50 maybe an option too.

 

[Brit33]

Originally Posted By: supercity
Originally Posted By: Brit33
Originally Posted By: supercity
Why not add more 10w60?

I've seen a UOA where Castrol Edge 10w60 sheard from 24 to 19 cst in only 2000km in an Alfa JTS engine.


ahh I've done 3500 kms and noticed a small drop in pressure. I push my high revving alfa pretty hard.

So you recommend just sticking with the 10w60 and doing a change instead of mixing?
If I need to change it every 3500 kms it gets a bit pricey.

or maybe go back to the Motul 300v? (same HTHS)


I just think 300v is a bit of an overkill. A cheaper oil with the same HTHS should be fine. A decent 20w50 maybe an option too.



the only 2 oils here with a hths of 5.2 here are these 2(300v and tws). same price also.

l.moly 10w60 here is even more expensive

 

[OVERKILL]

Originally Posted By: Brule
BMW trusted the Castrol TWS 10w60 in my '06 M Coupe for 24000 km. If you're concerned about it shearing, then it's probably become a 50 weight...but you're considering 5w40...one more grade lower. I'd stay with just TWS for the full Alfa recommended OCI; if it's been a good fit for this engine don't be concerned about a small drop in pressure. If this drop in pressure continues, then of course go back to the Motul 300v.


From the UOA's I've seen, it shears into a 40-weight.

 

[Brit33]

Originally Posted By: OVERKILL
Originally Posted By: Brule
BMW trusted the Castrol TWS 10w60 in my '06 M Coupe for 24000 km. If you're concerned about it shearing, then it's probably become a 50 weight...but you're considering 5w40...one more grade lower. I'd stay with just TWS for the full Alfa recommended OCI; if it's been a good fit for this engine don't be concerned about a small drop in pressure. If this drop in pressure continues, then of course go back to the Motul 300v.


From the UOA's I've seen, it shears into a 40-weight.

after how many kms?

Maybe back to the 300v?
Can't remember is ester based oil more resistant to fuel dilution btw?

 

[Brit33]

What's the HTHS of Liqui Moly 10w60?

Shear resistance good?

 

[OVERKILL]

Originally Posted By: Brit33
Originally Posted By: OVERKILL
Originally Posted By: Brule
BMW trusted the Castrol TWS 10w60 in my '06 M Coupe for 24000 km. If you're concerned about it shearing, then it's probably become a 50 weight...but you're considering 5w40...one more grade lower. I'd stay with just TWS for the full Alfa recommended OCI; if it's been a good fit for this engine don't be concerned about a small drop in pressure. If this drop in pressure continues, then of course go back to the Motul 300v.


From the UOA's I've seen, it shears into a 40-weight.

after how many kms?

Maybe back to the 300v?
Can't remember is ester based oil more resistant to fuel dilution btw?


IIRC, it was a 50 by 3,000 miles and by 5,000 miles it was a 40-weight in the M5's

This is going by memory, so the intervals might be off.

 

[Brit33]

hmm my wife came back from a 45 min trip last night, all town driving, oil was at 90c, so she would have been using the idle circuit mainly.

Pressure was back up at the normal level as when new.

I'm now suspecting the larger main jets I put in was diluting the oil slightly while on a fast highway run last weekend.
At 95c oil temp on the highway the oil should be burning off most fuel no? Not much to worry about?

 

[Brit33]

Found a company Finning that may do UOA's here. I wrote to them to see how much and how it's done.