TheSamba.com :: View topic - van runs quieter in warm weather (75F+) why?

Thu Jul 20, 2023 3:13 pm

Where I live, it rarely gets warmer than 65F. 70+ feels hot.

With that, I was taught to run Castrol GTX 20w-50, across the board. So that's what I've been running.

I've had noisy lifters that have quieted down a bit over time at first mostly due to swapping a couple lifters, FI harness seems to have made a difference in noise level as well.

Recently, I've been driving into much hotter weather, 80-100F, long slog drives, and the van is driving very well, better than ever really, and lifter noise is 100% gone when it's this warm.

Could my oil be too thick for the cool coastal weather? What do you guys think?

Thu Jul 20, 2023 3:33 pm

0-40 Mobile1 synthetic is where its at!

Thu Jul 20, 2023 3:51 pm

Castrol GTX Classic 20w-50 is a great oil for most climates. You are fine.

Thu Jul 20, 2023 4:13 pm

Red Ryder wrote: Castrol GTX Classic 20w-50 is a great oil for most climates. You are fine.

That's what I've been taught by my 30+year of Vanagon maintenance Vanagon Guru.

I am wondering, however, why the van is substantially less noisy in warmer weather. Sounds like a completely different vehicle, to the point where, when at a stop light, I'm wondering if it's stalled!

Oil viscosity, temperature, and lifters are my first thoughts

Thu Jul 20, 2023 4:24 pm

vanis13 wrote: 0-40 Mobile1 synthetic is where its at!

From a 30+ yr VW maintenance and Vanagon engine building guru.

Most damage is done upon startup, why start it in molasses?

Oil today is WAY different than oil 40 years ago.

40w top end is really nice. Starting to move oil around sooner than later is even nicer.

It gets tiring to go against (old) conventional ?logic?...If one thinks it through, it makes sense.

Glad everyone gets to put in their engine what ever they choose.

Thu Jul 20, 2023 5:18 pm

vanis13 wrote: vanis13 wrote: 0-40 Mobile1 synthetic is where its at!

From a 30+ yr VW maintenance and Vanagon engine building guru.

Most damage is done upon startup, why start it in molasses?

Oil today is WAY different than oil 40 years ago.

40w top end is really nice. Starting to move oil around sooner than later is even nicer.

It gets tiring to go against (old) conventional ?logic?...If one thinks it through, it makes sense.

Glad everyone gets to put in their engine what ever they choose.

This is what I was wondering about and it makes sense. I'll have to give it a go next oil change. Thank you

Thu Jul 20, 2023 5:34 pm

vanis13 wrote:
From a 30+ yr VW maintenance and Vanagon engine building guru.
Most damage is done upon startup, why start it in molasses?

Its real hard to prove because nobody ever spends a lifetime starting their engine.
And they log no miles doing so, thus have no data.
It could be a husband’s tale.
I said it for many years but don’t believe it anymore.

Startup is almost a “no load” condition, and its short.
The oil is thick and protective.
Not much is being asked of the engine.

I suspect most damage is done when the oil is old and contaminated.
And perhaps engine damage escalates when the engine is producing maximum output - while the oil is contaminated, hot, thin.
High torque output for extended periods is what accumulates.
Try holding RPM at 3600 for an hour in your driveway.
On the freeway the engine does that, pushing a 4x8 sheet of plywood ag 65mph through the air with about 90 hp.

That makes most sense to me that most engine wear happens at the top of the torque curve (not the bottom).

The only thing about startup being wasteful is the fact that the engine is producing nothing therefore really bad in the efficiency equation.
But you can’t skip it.

The other day I thought my van was running really nice, quiet.
But I was at the bottom of a mountain pass and then my “ears popped”.

Hydraulic Lifter clatter makes sense WRT viscosity.

Thu Jul 20, 2023 6:14 pm

Sodo wrote: vanis13 wrote:
From a 30+ yr VW maintenance and Vanagon engine building guru.
Most damage is done upon startup, why start it in molasses?

Its real hard to prove because nobody ever spends a lifetime starting their engine.
And they log no miles doing so, thus have no data.
It could be a husband’s tale.
I said it for many years but don’t believe it anymore.

Startup is almost a “no load” condition, and its short.
The oil is thick and protective.
Not much is being asked of the engine.

I suspect most damage is done when the oil is old and contaminated.
And perhaps engine damage escalates when the engine is producing maximum output - while the oil is contaminated, hot, thin.
High torque output for extended periods is what accumulates.
Try holding RPM at 3600 for an hour in your driveway.
On the freeway the engine does that, pushing a 4x8 sheet of plywood ag 65mph through the air with about 90 hp.

That makes most sense to me that most engine wear happens at the top of the torque curve (not the bottom).

The only thing about startup being wasteful is the fact that the engine is producing nothing therefore really bad in the efficiency equation.
But you can’t skip it.

The other day I thought my van was running really nice, quiet.
But I was at the bottom of a mountain pass and then my “ears popped”.

Hydraulic Lifter clatter makes sense WRT viscosity.

bear with me please, i'm still figuring things out, in laymans terms

do you think it's possible that warmer weather contributes to less lifter clatter or is it the viscosity of the oil in general?

I'm trying to take in as many perspectives, experiences, and knowledge as possible on this one

Thu Jul 20, 2023 7:57 pm

Sorry that was mostly just chatting around the campfire.

If you had a digital engine temp gauge it would probably show 195deg in hot weather and 194deg in cold weather.
The same.

I can’t think of a genuine reason it would have less clatter in hot weather. Some Subarus have intake air temperature sensors that could affect how the engine runs but not the valve clatter. I don’t know about the WBX.

A guage could add some interesting detail to the discussion.

Thu Jul 20, 2023 9:59 pm

Sodo’s on it…plug in a temp gauge & report back.

Whatever oil you’re using, toss 4 oz. MMO* in with each oil change…it’ll get & stay quiet.
(FWIW: Only 15 years on my WBX says so…first 10 years running 20w-50, now 15w-40.)

I have similar ambient summer temps to you here on the shore of Lake Superior.

Assuming your cooling system is up to par, ambient temp has little effect on oil temp.

Might be time for a coolant system flush & refill, &/or overhaul… <shrug>

8)

- Dave

*Marvel’s Mystery Oil

Fri Jul 21, 2023 4:51 am

Sodo wrote: I can’t think of a genuine reason it would have less clatter in hot weather..

A guage could add some interesting detail to the discussion.

One could be that the engine/situation finally gets hot enough to make use of that 20w on the low side of the oil you are using. Until then it's trying to push around molasses.

OIL temp and pressure gauges is what would yield relevant data.

Oil and coolant/("engine") temps can be different.

Depending on system config (design, where the pressure sensor is, viscosity), pressure and lubrication can be different.

Fri Jul 21, 2023 6:43 am

A thermostat stuck in the open position combined with cool weather would keep things chilly back there... Once you get to a warmer place the engine finally warmes up to operating temps... Oil pressure and temperature gauges are what you need to really know what's going on. That being said, where I live in CA I see winter morning lows that are frequently in the upper 20s and summer afternoon highs that are frequently in the 100s. I run Castrol 20/50 year round and have never noticed a difference in sound unless the van sits for several days and a lifter bleeds down.

Hans

Fri Jul 21, 2023 6:58 am

sound travels differently at dif temps and air conditions. your hearing isnt a constant either. the oil tales of viscosity damage are vestigial from air cooled motors where thats a larger factor, i used to believe the 'start up myth' too ,now ,not so much. clean debris free oil is all that matters. report back with decibel readings at dif temps, then well talk!