15/50wt or 10/60wt synthetic for aircool engine?

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sagaboy

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May 8, 2005
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Malaysia, Kuala Lumpur
Hi everyone,
I am from Kuala Lumpur, capital of Malaysia with day high temperature of 38C during traffic jam and low 20C at night.

I have a 40 year old aircool VW bug and have recently changed its transmission dino gear oil to 75/90 wt synthetics and experience fantastic improvement in gear shift plus a sudden jump of 300 RPM in engine idling speed (from 900 to 1200) therefore based on that experience, I believe that changing my current dino 20/50wt engine oil to synthetics may improve overall engine functionality and would like to seek some opinions or suggestions.

1. Shell synthetic 15/50 wt – because it is closest to my current dino 20/50 wt
or
2. Castro synthetic 10/60 wt – because Castro don’t sell any other grade in Malaysia

Will appreciate any suggestions or recommendations, thanks.
 
quote:
Originally posted by sagaboy:
Hi everyone,
I am from Kuala Lumpur, capital of Malaysia with day high temperature of 38C during traffic jam and low 20C at night.

I have a 40 year old aircool VW bug and have recently changed its transmission dino gear oil to 75/90 wt synthetics and experience fantastic improvement in gear shift plus a sudden jump of 300 RPM in engine idling speed (from 900 to 1200) therefore based on that experience, I believe that changing my current dino 20/50wt engine oil to synthetics may improve overall engine functionality and would like to seek some opinions or suggestions.

1. Shell synthetic 15/50 wt – because it is closest to my current dino 20/50 wt
or
2. Castro synthetic 10/60 wt – because Castro don’t sell any other grade in Malaysia

Will appreciate any suggestions or recommendations, thanks.
Click to expand...
Your car has lived happily for so long on Dino motor oil, and you want to change to Synthetics? Don't do it. Stick with what has served you so well.

Btw, what brand 75w90 Synthetic did you put in yout transmission?
 
Gotta see what Doug Hillary says about this, because I know he loves the 10W-60, however my old VW had no oil filter and only a strainer, so with short oci's, synthetics were not economically feasible. I alway just ran Castrol dino in my 1969 bug and kept the oci short.
 
Lots of little gaskets, o-rings, and such that are subject to oil seepage because of that air-cooled design. If you leak now, synthetic will most likely make it worse. I have an air-cooled 4 cyl porsche engine that I'm running straight 30 weight dino that was originally spec'd for 30 weight. I've used the 20w50 as have many others who have the same car/engine and I don't see the advantage of the 20w50. The engine rebuilder also recommended 30 wt. The engine was also converted to a full-flow filtration system that seems to keep the oil cooler with the external plumbing and large filter - Fram HP1 equivalent. Ambient summer temps in Sacramento right now is probably 70-100+F.
 
The old VW transaxles used bronze syncros, so GL4 would be good. I always wondered why syncros would not last in VW's, not knowing that older EP gear lubes were corrosive to "yellow" metals. Redline has the MT90 product for that type of application.
 
Hi,
the subject of viscosity in a VW was alive and well even in the 1960s

Older vehicles seem to perform better on a HD20w-30, HD30 or HD40 depending on the ambient temperature
These oils will tend to cool the engine better due to the oil "thermostat" cooler set up as noted by Jimbo

Sagaboy - Many owners also have a trouble free life with modern mineral multigrades like you are using now

If the car was mine (and like "ediamiam" does in his Porsche) and I would try what "haley10" suggests - try Castrol's HD40 first in your climate. If it does not leak or consume more go down to HD30

Regularly check the valve clearances, make sure all air duct work is in place, all cooling fine are clean - and always clean the sump screen with every OC

Best of luck
Doug
 
Just for discussion purpose, aside the negative points of using synthetics on an aircool engine are there any plus points..

“…I have a 40 year old aircool VW bug and have recently changed its transmission dino gear oil to 75/90 wt synthetics and experience fantastic improvement in gear shift plus a sudden jump of 300 RPM in engine idling speed (from 900 to 1200) therefore based on that experience,
I believe that changing my current dino 20/50wt engine oil to synthetics may improve overall engine functionality and would like to seek some opinions or suggestions.”


Will synthetic oil in the engine also generate equally as good an improvement as I have experienced with the transmission?
 
Sagaboy, welcome to BITOG! Synthetic oil can offer improvements in the VW aircooled engine. I agree with Doug and others' comments and suggestions so far. If your engine is not newly rebuilt (and resealed), you may have leak or consumption issues. Synthetics can help a hot-running aircooled engine to live and run like- new a lot longer, especially with the extreme heat that you have there. On the downside, the much higher cost may not outweigh these benefits. As was mentioned, you may not want to extend your oil change interval due to the "bugscreen" oil filtration system on a stock Beetle engine. A real oil filter can be added to those engines and would definitely help reduce wear and allow one to extend the OCI more when using a synthetic engine oil. Of course, one would probably want to have that upgrade done by someone who knows these engines well or rebuilds them.
If it was me, I would use a quality dino HDEO, either a straight SAE 30 or a 15w-40, changed every 2000 miles or so due to that extreme heat and poor filtration. Frequent valve adjustment is also a must too. Good luck whichever way you decide!
 
Caltex Delo 400 in 15W-40 is what I run in the 1968 and I wil probably try in the aircraft conversion VW that I am building. VW engines do not seal well and synthetics find leaks that dino oils cant.

Viscosity is another debate in the aircooled VW community. Those engines originally spec'd SAE 30 and yet 20W-50 is very popular. The stock oil pressure relief system sends oil to the cooler automatically as it thins, and bypasses the cooler otherwise. Since the car lacks both oil temperature and pressure gauges, it is difficult to tell what is really going on. Aircraft at least are required to have both. Clearances are not as big as on large aircraft engines that do specify SAE 50, so some VW engine builders create extra oil passages in the valve train area to increase oil flow.
 
Id consider the delo 400 if you could get that... 20w-50 is probably a ghood choice if you do a lot of hill climbing, etc.

All in all, strive for the smallest viscosity spread, and if you havent changed any gaskets (and dont want to), keeep with a dino oil.

JMH
 
To answer your question in the last post, I would say that you would definitely see performance improvements using a quality formulated synthetic SAE 30, 15w40, 15w50, or 20w50. I have personally used Mobil 1, Amsoil, and Valvoline and have no complaints for any of them, but I don't know if they are readily avaiable in your area. Of the 2 that you mentioned, use the 15w50. I see no benefit to the 10w60 since this wide viscosity range is not needed in this engine/climate. You would have to see what viscosity works best in your engine in its current condition, probably the 15w50 or the 20w50, which you are currently already using. On the up-side, that engine only holds 2.5 to 3 liters of oil, if I remember correctly, so maybe it would not be so expensive to go synthetic after all, even changing it at a regular interval (vs. extending the OCI while using a synthetic).
 
I'd say go ahead and use Shell Helix Ultra. You wont get oil leak issues from a Group III oil. Other Group III choices would be Esso Ultron or Caltex Havoline.
 
My engine has been newly resealed with zero oil leakage, after digesting everyone suggestions, my conclusion is that; it is not exactly the higher cost synthetic, with only an additional of $15 for every 2,000 miles oil change that may improve engine performance exceeding $15 in value without degrading anything else seems to be a sensible way to try something out, thanks for all the suggestions
smile.gif


Over here, M1 cost $40 per 4 liters, M1 Gold at $50 per 4 liters and others like Amsoil, Valvoline, Shell at $35 per 4 liters, Group III (semi-synthetic) half the price of synthetic and dino like Castro GTX 20/50 $7 per 4 liters, mono HD 30 or 40 are the cheapest at $4 per 4 liters.
 
quote:
Originally posted by Jimbo:
Shell Helix Ultra is way overpriced here in the US, due to availability only at exotic car dealers, something like $30US/liter. Is it commonly available in Asia?
Click to expand...
Yes it is. And it's hardly exotic - not even real synthetic
wink.gif
 
Paul, I don't have a problem with Group 3 at all. I still have good 'ol Castrol Group 3 5W-30 in one of my cars.....and it's performed brilliantly ! (gasp ! shock horror !
grin.gif
) I just object to the price they charge for Gp 3 oils.

Sagaboy - I was in KL last week. It was very humid, but the temps never got to 38C. Plenty of Sagas around as well
wink.gif
Lots of dodgy roadside mechanics/workshops too. I still can't believe how nuts the Malaysians go over the Perdana, and how expensive cars are over there.
 
quote:
Originally posted by Losiho:
Paul, I don't have a problem with Group 3 at all. I still have good 'ol Castrol Group 3 5W-30 in one of my cars.....and it's performed brilliantly ! (gasp ! shock horror !
grin.gif
) I just object to the price they charge for Gp 3 oils.
Click to expand...
cheers.gif
 
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