Topic: 1996 B3000: 10W30 vs 5W30 oil for winter?

[davidy]

For the past two winters, my 1996 Mazda B3000 4x2 truck has been parked. However, I am considering using it on a part time basis this winter.

Currently, it has 10W30 oil (change done around May or June 2011). Normally, I would use 5W30 oil...in the recent past, I have had an ongoing minor oil leak...apparently stopped leaking oil after I switched to 10W30. My mechanic told me that he would have to drop the oil pan in order to fix the oil leak. I didn't want spend very much $$$ on an older truck....and therefore, left it as is. NOTE: Conventional oil has always be used in my truck.

Winters usually go down to as cold as minus 40 deg C (in the long past was reported to go down to minus 50). Long stretches down to minus 25 to minus 30. Usually only a few days to a week below minus 30.

Recommendations?

If it's too cold, snowy or icy, I can use my Ranger 4x4 instead. Cutoff temp for the Mazda...minus 20 deg C?

BTW, I have a new battery this spring.

Dave

[PJungnitsch]

0w30 synthetic is the only one that was significantly better when I tested them. 10w30 or 5w30 didn't make any real difference, even in synthetic.

If you want to know for sure put a sample of each of the oils you are considering in the freezer with a thermometer and check for yourself.

[Gardiner Westbound]

Your local mechanic is your best source for advice, especially when he has kept the truck running for 15-years. He's clearly doing the right things, right.

I would consider a block heater and a battery warmer if you have electricity near the truck. Put them on a timer.

Synthetic motor oil has a lower pour point than conventional oil, but I would be hesitant put it into a 15 year old truck that has thrived on petroleum oil. Nor would I go thinner than the factory spec 5W-30 viscosity. That will undoubtedly worsen the oil leak.

[PJungnitsch]

I switched to 0w-30 synth when my truck was 14 years old. No increased leaking or burning in the ten years it's been in since.

The 0w-30 I used, Castrol, is actually a fairly heavy oil when warmed up. It just doesn't turn into solid grease when the temp drops.

[rrocket]

+1 on 0W30

[davidy]

I switched to 0w-30 synth when my truck was 14 years old. No increased leaking or burning in the ten years it's been in since.

The 0w-30 I used, Castrol, is actually a fairly heavy oil when warmed up. It just doesn't turn into solid grease when the temp drops.

If the truck leaks oil with 5W30 conventional (not with 10W30), wouldn't it likely leak with any synthetic?

Already have a block heater. Will probably also use a 2A smart trickle charger.

Dave

[PJungnitsch]

If the truck leaks oil with 5W30 conventional (not with 10W30), wouldn't it likely leak with any synthetic?

Already have a block heater. Will probably also use a 2A smart trickle charger.

I doubt the 5w to 10w made any difference, in my experience leaks can change randomly on their own as the gasket material or o-ring shrinks and swells/shifts around/etc and it probably just coincided with the oil change.

But if you have the truck plugged in any oil will work fine as far as cold weather goes.

[mrthompson]

My vote is for 5W30 high mileage oil.

[davidy]

If the truck leaks oil with 5W30 conventional (not with 10W30), wouldn't it likely leak with any synthetic?

Already have a block heater. Will probably also use a 2A smart trickle charger.

I doubt the 5w to 10w made any difference, in my experience leaks can change randomly on their own as the gasket material or o-ring shrinks and swells/shifts around/etc and it probably just coincided with the oil change.

But if you have the truck plugged in any oil will work fine as far as cold weather goes.

There have been at least two (maybe three oil) oil changes with 10W30....none of which have leaked. 5W30 leaked every time.

It's got low kms (just over 150,000 km on a 15+ year old truck)....maybe the next oil change I will go with high mileage conventional oil (still undecided about 5W30 vs. 10W30)....someone recommended Valvoline Maxlife higher mileage oil.

http://www.valvoline.com/products/consumer-products/motor-oil/higher-mileage-motor-oil/2

Dave

[ktm525]

I vote 5W-30.

I will try to dig up the graphs (form Bob is the oil guy) but it was surprising that Castrol syntec 5W-30 actually had a lower viscosity at -18 C vs Castrol syntec 0W-30. Ultimate low temp flow went to the 0W of course. I think the viscosity flow numbers crossed at -30 or so.

Essentially the viscosity vs temp for these oils were not straight but curved. At certain cold temp ranges the %w actually flowed better.

[davidy]

Shop got Pennzoil High Mileage 5W30 instead. We will see how it works this winter....hope that the "leak" doesn't start up again.

DAve