engine warm up between two oils?

[xtell]

I've encountered an interesting change in engine warmup time this last winter and would like some input from board members. I drive 7.8 miles from my house to work five days a week. During the winter we had long streatches of cold weather (below 32 degrees). I leave my house at 4:30am and all but one of the traffic lights are flashing so I don't have to stop for each light. I drive the same route each time and the same speed. I had Quaker State Horsepower 5w-30 oil and a Purolator classic filter installed and according to the engine temperture gauge, it always took 5.5 - or more miles for the gauge to read at full temperature. I changed the oil out for Pennzoil conventional 5w-30, same filter (weather temperature the same as with the GS oil) and the truck would reach full engine temperature at 3.5-4.0 miles on a consistant basis. Is there a reason why one oil would cause an engine to warm up faster than the other? Truck is a 2004 Toyota Tacoma, 3.4 engine, automatic. This has really got me stumped?

 

[pidster]

I can't imagine a way the oil could be responsible. If you filled it up with a way too thick oil or something than maybe a slightly faster warmup, but between two 5w30s I just cant imagine how. It's gotta be caused by something else.

 

[labman]

My vote is for something else. Go back to the QS next winter and report back.

 

[xtell]

Thanks for the replys. The change in warmup distance happened immediately after the oil change. All of the other fluids in the truck: radiator, steering, transfer case, rear diff, break fluid, were changed out last summer. Engine runs fine, no check engine codes, tires properly inflated, no barking brake hang up. I'm going to monitor the warmup distance - time switching between the two mentioned oils during the rest of the year and see what develops.

 

[jorton]

Originally Posted By: xtell
I changed the oil out for Pennzoil conventional 5w-30, same filter (weather temperature the same as with the GS oil) and the truck would reach full engine temperature at 3.5-4.0 miles on a consistant basis.


"Full engine temperature" translates to full coolant temperature so I would think the change you observed is related to the thermostat, heater, temp sender or the coolant.

 

[rclint]

I had a Dodge with the Cummins Turbo Diesel, and I noticed when I changed from Delo/ Shell Rotella to Rotella T that it took me several more miles before warm-up. It also made the engine quite as well, much more so upon startup on a cold morning, and even after warm. The longer period before warmup was a drawback for me cold mornings waiting on 3 gallons of oil, and I can't remember the radiator capacity made for some long cold drives before any heat. As for it had to be something else on this particular truck I'm 100% sure it was the oil.

 

[rclint]

jorton full engine temp is related to heat generated from the engine as the items you mentioned are in place to dissipate heat, heat, measure temp etc. If I had not seen this in person on my truck I would also think it had to be something else, however after observing the Cummins Turbo Diesel I think it's possible to highly probably the oil could have cause the difference.

 

[mechtech2]

xtell - Don't be stumped. It's only one OCI and one observation.
2 very similar 5-30s are not going to chagne the coolant temperature.

 

[GSDad]

If you increased the internal engine friction enough to cause it to heat up faster, and yes that's very possible, you should also notice a decrease in gas milage.
GSD

 

[jstutz]

This would be an awesome case for some experimenting. My guess is that oils can have different friction characteristics because of the additives used. Knowing that thinner oil conducts heat more efficiently, could the dino be thicker in the cold, causing more internal friction during the warm up cycle. It would be interesting if maybe you ran a 5w20 or 15w40 and see if you could link the warmup cycles to a viscosity. This may be hard to do because most oils have different levels of additives as well as different temperature characteristics. Either way, keep good records and maybe you can come up with some sort of conclusion. I have noticed this before on my old truck that i normally run 15w40 in. I ran a run of M1 5w30 in it and swore it took longer for the temp gauge to get to full temp, but never really payed too much attention.

 

[Tucson Five-O]

I've noticed the same thing when using Group III or > oils as compared to Group II/II+ oils in my 2008 Impala with the 3.5L V-6.

Even here in Southern AZ with mild winter weather, during warmup I see the coolant temperature hesitating around the thermostat opening temperature which is 185F (coolant inlet temperature) for about a mile longer than when I use the conventional (Group II/II+ oils). With the conventional oil the coolant temperature rises smoothly to 192F before stabilizing. And no, there is nothing wrong with the thermostat and the changes are very repeatable as well.

I also see a very slight mpg increase using Chevron/PYB over PP. I don't know if it's because of the above phenomenon or whether it's because most modern SM GF-4 5w-30 oils more quickly shear down to about 9.0 (I believe by design, I call them 30-ino's -30wt. in name only), as opposed to PP which I've seen maintain its viscosity through the OCI of at least 9.5.

Take care,
Gary

 

[Tucson Five-O]

I think it may have something to do with the slightly greater friction reducing properties of the Group III or > oils. This in turn increases (albeit very slightly) the time for the coolant temperature to stabilize. I bet the oil temperature is slower to stabilize as well.

I had noticed this 10+ years ago in a 1994 Honda 2.2L I-4 running Mobil1 0w-30. That engine had superb coolant temperature control. It was noticeably slower to reach operating temperature with the Mobil1 as opposed to when I used PYB (my favorite conventional oil).

On the other side of the spectrum the Mobil1 really came into its own when run in 110F+ heat on a 5% grade. The conventional oil would allow the engine temperature to rise out of the normal range, but the M1 kept it right there. I think that was another indicator showing the difference in specific heat capacity (an engineer might label this specification differently but you get the idea).

Thanks,
Gary

 

[Tucson Five-O]

My last thoughts on this matter.

Modern engine designers have worked hard to reduce internal friction (parasitic losses). Therefore any slight change in friction reduction due to using a different group oil, I mean Group 3 or >, compared to Group II/II+ may have more of an effect than in the old days with a large stroke V-8 running at higher rpm in a heavier vehicle.

And concerning Tig1's comments about it being an interesting area to experiment with, I have noticed this phenomenon using Chevron 5w-30 with a 59.5 40C viscosity which is close to PP 5W-30 with 57.5 40C viscosity, so I think the oil composition is more responsible than the slightly differences in viscosity, particularly here in So. AZ.

But as Caterham frequently points out the viscosity differences are much greater below 20C. My observations were made with the temperatures from 30-45F.

Take care,
Gary

 

[jorton]

I've been looking for a good reason to do synthetic summer oc in both cars.

Now I read in winter engines warm up faster using dino, and in summer engines run cooler using synthetic.

Good enough.