Older vehicles=thicker oils

[SteveSRT8]

It can mean many things, as simple as sludge and much more complicated reasons.

I always use consumption as my guide. A step up in viscosity has almost always stopped my very high mileage vehicles from using oil.

 

[Michael_P]

On engine tear downs with high miles, I have noticed oil pump gear clearances open up more than do main bearing clearances. This is not a hard fact, rather my observations. Another observation; Years ago when I worked as a field mechanic and used those hand crank barrel pumps to deliver oil from a drum. When it was around 0°F, the 0W40 and 5W40 oils got to the end of the neck of the barrel pump spout faster than anything. Way faster than 15W40 and 40W. Considerably faster than a 5W20. Keep in mind, this is not scientific evidence, rather my observations over time. Furthermore, there could be minute temperature differences I am not factoring in too. All hand crank barrel pumps were made in India with loose pump clearances.
I just thought I would stoke the coals a little.

 

[CATERHAM]

Originally Posted By: Capa
Caterham, it seems that you've been keeping track of your oil pressure numbers with different oils. Have you seen any kind of drop in the OP as the engine has aged in any of your vehicles?

I have but not in a modern engine.
Originally Posted By: Capa


So are we all saying that more than likely for the modern engine this idea about as it ages to go with a thicker oil is a myth?

I'd say it's old school thinking.
It's also marketing in NA with the proliferation of "high mileage" oils. The suggestion that 75,000 miles is high mileage in a modern engine is nonsense. One thing I will say about these these HM oils is that they are only slightly heavier than the spec' oils; enough to raise the OP 3-5 psi at most. In a very high mileage engine that typically is all that's necessary to restore normal OP.

 

[SS1970chrysler]

I'd agree with the above. The only "modern" engine I've had to go up on viscosity due to age/wear was my sister's 92 Plymouth w 2.9l.
Had to substitute 1 qt of 10w-40 each OCI to keep oil light from flickering at idle. Car had 120k at that time.

 

[LeakySeals]

Originally Posted By: Capa
I am still looking for the answer for those who have oil gauges: does the oil pressure change as an engine ages?


Back in the late 70's, 80's and early 90's the answer was yes, the older the car got, the less pressure they had according to the gauge. Adding thicker oil increased pressure. None of the cars I've had recently have oil gauges. Never lost an engine from a tick. Only lost one engine and it was from a lack of oil pressure. A Plymouth duster with a slant 6.

 

[LeakySeals]

Thanks Doug Hillary for the reply, still in the learning phase. I plan to buy a OP gauge, let the car tell me what it likes for weight.

 

[Capa]

Originally Posted By: LeakySeals
Originally Posted By: Capa
I am still looking for the answer for those who have oil gauges: does the oil pressure change as an engine ages?


Back in the late 70's, 80's and early 90's the answer was yes, the older the car got, the less pressure they had according to the gauge. Adding thicker oil increased pressure. None of the cars I've had recently have oil gauges. Never lost an engine from a tick. Only lost one engine and it was from a lack of oil pressure. A Plymouth duster with a slant 6.


So it seems that we are getting consensus that some high mileage engines did need thicker oils but that may not be true in a modern engine. Has anyone seen a +2000 engine lose oil pressure as it aged?

 

[SteveSRT8]

None of you guys have any engines old enough!

On our fleet vans they spec 5w-30, and we use that for the first 150-200k miles. At some point they will begin to consume oil a bit, then we simply go up a grade.

This completely stops consumption. It rarely makes any discernable difference in oil pressure. Frankly we do not worry much about oil pressure anymore.

When was the last time anyone experienced an oil pressure related failure?

 

[Doug Hillary]

Hi,
perhaps we need to qualify what "Older vehicles" really means.

These are the viscosities specified for some Older vehicles

Early 1930s
>90F = 40
50-90F = 30
15-50F = 20
-15-+15 = SAE10 or 90/10 SAE20 and kero
kero or 80/20 SAE20/kero

In 1940
>90F = 30,40 and limited 50
>32F = 20W, 20, 30
>10F = 10W, 20W
>-10F = 10W
kero

Interesting?

 

[OceanDoctor]

I'm using 0w20/0w30 blend in the high mileage Camry. Runs as great as it ever has, very quiet also. It sees rather hard driving, most days it'll see pedal to the ground and 170km/h(110mph). I see zero need for thick oil, in fact I changed out QS 5w30 early to get the 0w blend in there.

I should add, oil pressure is excellent. 80-90psi@3000+rpm in -15C weather. >10psi hot idle. 45-50psi@2500rpm hot.

 

[LeakySeals]

Originally Posted By: OceanDoctor
I'm using 0w20/0w30 blend in the high mileage Camry. Runs as great as it ever has, very quiet also. It sees rather hard driving, most days it'll see pedal to the ground and 170km/h(110mph). I see zero need for thick oil, in fact I changed out QS 5w30 early to get the 0w blend in there.


What is the reason you rush to get 0w blend in? Do you have an OP gauge, or or just going by feel and sound to determine engine health? Trying to understand thanks.

 

[hooligan24]

i think its funny when I read on another forum that I am part of, that most of the members think their motors are high mileage and many of them do unnecessary rebuilds on them when they get close to 100k miles. The forum is full of younger people that believe in running 20w50 and changing the oil every 2000 miles or 2 weeks, which ever comes 1st because the engine is turbocharged.

%(^$ hits the fan when someone mentions they change their oil every 5000+ miles.

As for my 2.4L, I have only 71k miles and the oil pressure is still the same as when installed the Oil Pressure and Oil Temperature gauges back around the 15k mile mark. The car has ~1200 roadcourse miles and many trips to redline.

 

[Capa]

Doug,
Your posts are always interesting and very informative. I've noticed that a couple have mentioned losing oil pressure in older engines with vehicles from the 70's, 80's and 90's. To me that seems quite modern. Perhaps this myth is in fact based on some truth?

 

[OceanDoctor]

Originally Posted By: LeakySeals


What is the reason you rush to get 0w blend in? Do you have an OP gauge, or or just going by feel and sound to determine engine health? Trying to understand thanks.


Yes of course I have an OP gauge! The rush was to get the 0w in there before the deep freeze happened

 

[1990LTD]

Originally Posted By: SteveSRT8
None of you guys have any engines old enough!




I dunno

 

[Doug Hillary]

Hi,
Capa - I don't think I've mentioned about losing OP! In all of my engines where an OPG was installed OP always remained within acceptable limits

Most German cars give a minimum hot idle OP and a minimum hot OP at prescribed revs. These tests are typically conducted with a prescribed viscosity oil and at a precribed oil temp of 80C - depending on the Manufacturer

 

[LeakySeals]

Originally Posted By: OceanDoctor
Originally Posted By: LeakySeals


What is the reason you rush to get 0w blend in? Do you have an OP gauge, or or just going by feel and sound to determine engine health? Trying to understand thanks.


Yes of course I have an OP gauge! The rush was to get the 0w in there before the deep freeze happened


What aftermarket brand did you use?

 

[OceanDoctor]

Originally Posted By: LeakySeals
Originally Posted By: OceanDoctor
Originally Posted By: LeakySeals


What is the reason you rush to get 0w blend in? Do you have an OP gauge, or or just going by feel and sound to determine engine health? Trying to understand thanks.


Yes of course I have an OP gauge! The rush was to get the 0w in there before the deep freeze happened


What aftermarket brand did you use?


it's an equus mechanical

 

[Bruce T]

This has been a great thread. I've especially enjoyed hearing from Doug Hillary and AEHaas.

 

[Capa]

Originally Posted By: Bruce T
This has been a great thread. I've especially enjoyed hearing from Doug Hillary and AEHaas.


We have several heavyweights that have contributed. I hope some more join.

Doug, so you have seen some variance with oil pressure but it was still within the acceptable range? How much did the oil pressure degrade as the engines got older?

What do you guys think about the old 10PSI/1000rpm recommendation? Say I got an oil pressure gauge (not sure if I'd go electronic or mechanical) and installed it in my GS400. How do I know what range is acceptable (I doubt I will find any Lexus literature that would tell me)?