HM oils

Status
Not open for further replies.
Joined
Apr 19, 2014
Messages
3,444
Location
WV
Just what is in HM oils that stops or slows oil leaks? Also do they contain more detergents?
 
Originally Posted by SirTanon
The consensus here is that HM oils have a slightly higher dose of detergents and a heavier dose of seal conditioners.

And are on the "thicker" side of the grade.
 
Originally Posted by demarpaint
... And are on the "thicker" side of the grade.
Not necessarily. See Pennzoil Platinum HM.
 
Originally Posted by demarpaint
Originally Posted by SirTanon
The consensus here is that HM oils have a slightly higher dose of detergents and a heavier dose of seal conditioners.

And are on the "thicker" side of the grade.


I have found the Valvoline Maxlife to be on the lighter side of the spectrum. Mobil 1 and most brands are generally of higher viscosity though.
 
HM oils have a larger dose of seal conditioners. Other things that differentiate it is a tad more ZDDP, most may be on the thicker side of the specified weight, more detergent is definitely included and makes the oil act like a mild flush, and you may even see a good dose of moly. I think many HM oils were API SL up until recent years (correct me if I'm wrong). Mobil 1 HM recently became an API SN oil. The only HM oil I can think of that is API SL still is Royal Purple HMX.
 
Originally Posted by demarpaint
Originally Posted by SirTanon
The consensus here is that HM oils have a slightly higher dose of detergents and a heavier dose of seal conditioners.

And are on the "thicker" side of the grade.


True ^^^^^

On both counts..

Havoline high mileage 5w30 has a HTHS of 3.4... And most others are above 3.2.
 
Originally Posted by SirTanon
The consensus here is that HM oils have a slightly higher dose of detergents and a heavier dose of seal conditioners.

What do they use for "seal conditioners"?
 
I don't recall any consensus except that HM oil are on the thicker side of the spec. Meaning that a thicker non HM oil would be the same ... I thought HM oils having extra seal conditioner and/or sweller were not substantiated?!
 
Status
Not open for further replies.
Back
Top