Does Thinner Oil Heat an Engine Up Faster?

[RinconVTR]

Could it be that heavier oils when cold, make the engine work a little harder? Enough to warm it up quicker? Just a thought...that wouldnt be worth trying IMO! Go Go gadget thermostat.

And a sheet of cardboard over the radiator = more aerodynamic car? I hope your talking about over the "grill" of a car or truck like 427Z06 had a link for...not flat sheet in front of the fins. (Jeez...thats all this forum needs are more myths.) 1.5 MPG improvment on that site...I think it would take a year just to pay for paper mache materials at that rate! And I bet it would look like you ran over a 4 year olds school project

 

[DracoFelis]

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Originally posted by RinconVTR:

And a sheet of cardboard over the radiator = more aerodynamic car?

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It can help, yes.

That's because the aerodynamic drag due to air going through the grill (and bouncing around in the engine compartment) is often a surprisingly large percentage of the total car aerodynamic drag (and aerodynamic drag is very important at highway speeds, although much less so around town). So if you don't need that much cooling, you can trade off some (potential) cooling for more aerodynamics. And in many cases this effect can be enough to see at the pump (as well as feel the lower drag when driving down the road).

FWIW: My car's grill block covers a little over 2/3 of the grill (I left the center by the license plate open for cooling), and I seem to have more than enough cooling (but I am keeping an eye on the temp gauge, just to be sure). And the effect is enough for me to feel "less resistance" when driving at highway speeds. And I think it is helping at the pump as well (but I haven't had it on long enough, to factor out the fuel economy factors of this mod, from the normal tank to tank variations in fuel economy).

BTW: For many of us the cooling system of their car is way over-designed for "normal driving" (especially if/when we are using synthetic oil in the engine, as synthetic oil cools better by itself, never mind what the cooling system is doing to help that along). So many of us could safely block some of their grill (to cheaply get more aerodynamics), and still have more than enough cooling left over...

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1.5 MPG improvement on that site...I think it would take a year just to pay for paper mache materials at that rate!

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The rate of return would depend upon how much you save, and the price of gas. Even with the recent price decrease, the price of gas is still quite noticeable IMHO...

BTW: Cardboard is great for a quick/cheap test. But if you really want a decent looking (grill block) that will last, use plastic (not paper). For example, I ordered a little black colored "Coroplast" (looks like corrugated cardboard, but it is made out of plastic) for my "grill block" (and I hold the plastic on with strong zip-ties). Unless you look very closely, you can't even tell any mod was done (as the black plastic blends into the black grill color so well, most people won't even see it is there). And as a bonus, the plastic is nice and "water proof" (i.e. doesn't have paper's problem with bad weather).

 

[Eddie]

I always used cardboard but, watch the temp gauge.

 

[mechtech2]

Go with an oil that starts well when it's cold out.
It is not you 'running cold problem', either way.
Put in a good thermostat, and block off the radiator partially, if necessary.

 

[Dr. T]

No, thinner oil generally makes the car (coolant temps) take longer to warm up. Another reason to consider using the proper weight per climate conditions.

 

[Ron AKA]

Agree with the suggestion to change the theromstat. I have a Olds with the same engine, and the thermostat failed open. You should also consider a 5w30 oil year around. Much better for the engine than a 10w30, as it will flow better at warmup. Won't help your engine warm any quicker though.

 

[JHZR2]

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No, thinner oil generally makes the car (coolant temps) take longer to warm up. Another reason to consider using the proper weight per climate conditions.

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Yep, Ive noticed this... my BMW, which is specced for 40 or 50wt oil, depending on the ambient conditions, had a 30wt oil put in when they replaced the headgasket. It was a mistake, but I told them to leave it, so I could see what it is like.

The temperature gauge gets up to 1/4 of the way just fine... but the needle sits at 1/2 when operating properly, and it is really slow to make it all the way to the 1/2... that last mm takes a good long time. Didnt used to, so I assume that the difference is in the oil weight.

JMH

 

[1sttruck]

Taking longer to warm up needs to be weighed against lower posible wear due to better flow. Volvo as I recall found that their heavy diesels had lower wear when using a 5w40 compared to a 15w40. I'd suggest using whatever is recommended for the conditions and then picking an oil with a low winter weight, like a 0w30 or 0w40.

 

[Rickey]

One more possiability: Could the heater core be partially plugged? And I agree with the t'stat being the most likely culpret.

 

[Nickdfresh]

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I always used cardboard but, watch the temp gauge.

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I don't have one. Just an "idiot light" on that model for whatever reason.

Personlly, I think it should be federally mandated that all cars have OEM gauges for everything!

Thanks for the repsonses to this thread. I will change the thermostat --unless it's wayyyy to tough to get at! And I may even try the cardboard thing, which I had never heard of before. I'm not too worried about "wear" since all the wear due to startup has been done to it by 178K, and the car is a definite "beater" that could blow up tomorrow, and I'd still've gotten my money out of it. But I'll probably use 5W-30 anyways for fuel economy and ease of starting issues. I even have the Havoline for it, unless of course someone takes the car off my hands.

But I think the preceding post may be the right diagnoses. The heater core may well be blocked. As I said, the car heats slowly, but it does heat up well eventually, but I have to drive like 20-minutes to feel warm, and it's ice-cold for 5-10 minutes.

 

[Brianv6]

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No, thinner oil generally makes the car (coolant temps) take longer to warm up. Another reason to consider using the proper weight per climate conditions.

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If you don't mind could you explain this? From what people have said in this thread that there car warms up faster with a higher weight oil. But you say to use the proper weight for the climate. So generally speaking 5-30 is good in the winter? Please explain in simple terms for the newbie.

Another person recommened 5-30 year round. GM spends millions researching engine performance. Why would they suggest 10-30 over 5-30? I know they are very similar but still

Brian

 

[Titan]

Would the biggest reason GM suggests 10-30 over 5-30 be because 10-30's stay in grade better/longer?

 

[Ron AKA]

[quoteIf you don't mind could you explain this? From what people have said in this thread that there car warms up faster with a higher weight oil. But you say to use the proper weight for the climate. So generally speaking 5-30 is good in the winter? Please explain in simple terms for the newbie.

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The more viscous oil will cause more loss of HP in the engine. This loss will help to heat up the oil. However, I would suggest this effect is very minor compared to other sources of heat (combustion), and this will be a very insignificant effect. It is much more important to consider the right oil for the temperature. A 5w30 oil will flow better and lubricate better during startup than a 10w30 oil.

 

[Sangamon]

I'm pretty sure thinner oils capture and release heat at a faster rate than does a thicker oil. But I don't know enought about it to say for sure.

Still waiting for someone in the know to chime in on this topic.

 

[Nickdfresh]

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I'm pretty sure thinner oils capture and release heat at a faster rate than does a thicker oil. But I don't know enought about it to say for sure.

Still waiting for someone in the know to chime in on this topic.

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I'll give it a shot...

5W-30 will flow a little faster at startup on those cold mornings, which theoretically means that the oil is removing harmful condensation and contaminants that get into the crank case a little faster, before the oil has a chance to heat up and burn them off, and to provide better cold lubrication. Slightly thinner oils can also lubricate the tighter tolerances, and flow through the smaller drain pin-holes, of newer engines at all temperatures.

Incidentally, GM recommends 10W-30 for certain years of the 3800V6 engine. Mine isn't one of them. 5W-30 is "preferred" with 10W-30 an option above 0-F.

In the mid-1990s, GM moved to 10W-30 as the "preferred" oil for many of their V6s. They've apparently moved back to recommending 5W-30 as an all temp. oil for the 3800 I hear.