Does anyone run 20wt in a car spec'd for 30wt?

[CATERHAM]

Originally Posted By: virginoil
Originally Posted By: Beagle2000
Not to start a war here or anything but why would you even want to consider or use a lower viscosity oil than recommended by the engine manufacturer?
They didn't come up with this decision to use a 30 wt by the spin of a carnival wheel. Some very in depth engineering and much testing is done before they spec an oil.
But hey if you've always wanted to blow up an engine and foot the bill then I say "fill yer boots".
I would chalk the question up to boredom as you had suggested.


You are not alone on this point.

Unless the OEM has back specified a 5w20 for the engine it is questionable.

Even the lightest 0W-20 oil you can buy is much heavier than optimum in all applications until the oil temp's get up to at least 70C.
If you maintain the minimum oil pressure as specified by the engine manufacturer then you are fully complying with the manufacturer's engineering requirements. In fact that is a much more precise method of optimizing an oil's viscosity selection for a particular application than going with a SAE grade recommendation.

I will also add that before the advent of 0W-30 and 0W-40 oils most manufacturer's including BMW and Porsche did recommend the use of 5W-20 oil when operating at certain cold ambient temperatures. Even today it is still beneficial to run a 0W-20 oil under such conditions. What has changed is that it is no longer necessary to specify an oil that can't also be used under hot operating conditions. This is an obvious plus for vehicle manufacturers in that it eliminates driver error; no longer can a grossly inappropriate oil grade selection be made, thereby minimizing warranty claims.

Finally, while a benefit can be realized in deviating from a manufacturer's specified oils, I never recommend the practice to others without a caution that they fully understand what they're doing. While small there is an inherent risk involved; you could after all it screw up.

 

[Garak]

Originally Posted By: CATERHAM
I will also add that before the advent of 0W-30 and 0W-40 oils most manufacturer's including BMW and Porsche did recommend the use of 5W-20 oil when operating at certain cold ambient temperatures.


That's exactly correct. My 1991 Audi specifies anything from 5w-20 to 10w-30 for our current ambient conditions. And in 1991, I didn't even know 5w-20 existed.

 

[il_signore97]

Originally Posted By: CATERHAM
Running a 20wt, preferably a 0W-20, in a Calgary winter should not be a problem with the way the OP drives his truck.

I've been running a 20wt in my BMW during our milder winters for the past 5 years. Engine is much more responsive when cold vs the M1 0W-40 I ran before. Oil temp's simply don't get above 80C when the ambient temp's below 5C.

But you may want to take il signor97's experience with his VG35DE into consideration although he didn't elaborate on hot the oil got in sub zero temp's; I suspect not very.
Of course if you want to fine tune your oil viscosity selection with 100% zero concern, install an oil pressure gauge.



I believe I've posted my measurements before, but it doesn't hurt to post them again. In sub-zero weather, the oil temps in my VQ will steady out around 100C under very easy driving. Some high speed cruising or spirited acceleration will promptly heat it to 120C. It is a bit slower to respond in sub-zero weather, but believe me, it still gets very hot. In terms of warm up, it only takes 4-5 min longer to get up over 80c in the winter than in the summer. Summer time oil warm up takes no longer than 10-12 min.

The OP's 4.0 V6 might be different. I'm mearly suggesting that he look into his oil temps under all driving situations that he will encounter before switching to a 20 grade oil.

 

[CarNewb]

OP go for it and if youre wondering where to get a cheap 5w-20 go to wal-mart they have the pyb on sale for 13 bucks in that grade

 

[sw99]

I run 5w20 year round in my Subaru EJ22. The car is spec'd for 5w30. I bought the car with 122,000 and it now has 161,000 and zero problems. I ran some 5w30 at first and after the switch, I did not notice any noticeable differences. Time will tell, but I plan on the continued use of the 5w20.

 

[D189379]

Originally Posted By: il_signore97


The OP's 4.0 V6 might be different. I'm mearly suggesting that he look into his oil temps under all driving situations that he will encounter before switching to a 20 grade oil.


I think the 4.0 and 3.5 are pretty close to the same. Definitely the same engine block. As long as I don't lose a lot of oil pressure and the warning lights stay off, I don't really know what harm I could do.

It will definitely be a full synthetic, as thats all my truck has ever seen.

 

[CATERHAM]

You can't rely on the oil pressure "idiot" light to tell you if you're oil is too light at higher rev's. You could easily be 5 to 10 psi below spec' and it won't trigger the OP light. You really need a proper OP gauge.

If as il signor97 suggests, that your engine does run hot, and 120C oil temps is hot, then I wouldn't run a 20 weight oil. Although I don't know how the oil can get hotter than the coolant temp's unless you're really hammering it and of course you're not.

 

[il_signore97]

Originally Posted By: D189379


I think the 4.0 and 3.5 are pretty close to the same. Definitely the same engine block. As long as I don't lose a lot of oil pressure and the warning lights stay off, I don't really know what harm I could do.

It will definitely be a full synthetic, as thats all my truck has ever seen.



Yes, our engine blocks are identical, but there could be other more minor differences that can result in oil temp differences between our two engines.

What is the oil capacity of your truck? My VQ only takes 4.2 L to fill right up to the H. If yours has more capacity, this could help act as a buffer. Also, I wonder if your oil to coolant heat exchanger is larger than mine. More airflow under your truck could help cool oil temps as well. My engine has oil piston cooling jets, which add heat to the oil. Not sure about yours.

All of these factors could mean that you might experience different oil temp behaviour than in my car. Caterham gives sound advice here... Check your temps before making the switch and/or evaluate pressure after doing so if you want the most safety margin.

I'll be honest. I've run 5w20 in my Chev Venture 3.4 L and it calls for a 30 grade. However, I know that in the winter (when I'm not towing) the oil temps do not generally get very high, so I'm perfectly safe. I am not very confident about running a 20 grade in my Nissan VQ though!!!

 

[D189379]

Originally Posted By: il_signore97
Originally Posted By: D189379


I think the 4.0 and 3.5 are pretty close to the same. Definitely the same engine block. As long as I don't lose a lot of oil pressure and the warning lights stay off, I don't really know what harm I could do.

It will definitely be a full synthetic, as thats all my truck has ever seen.



Yes, our engine blocks are identical, but there could be other more minor differences that can result in oil temp differences between our two engines.

What is the oil capacity of your truck? My VQ only takes 4.2 L to fill right up to the H. If yours has more capacity, this could help act as a buffer. Also, I wonder if your oil to coolant heat exchanger is larger than mine. More airflow under your truck could help cool oil temps as well. My engine has oil piston cooling jets, which add heat to the oil. Not sure about yours.

All of these factors could mean that you might experience different oil temp behaviour than in my car. Caterham gives sound advice here... Check your temps before making the switch and/or evaluate pressure after doing so if you want the most safety margin.

I'll be honest. I've run 5w20 in my Chev Venture 3.4 L and it calls for a 30 grade. However, I know that in the winter (when I'm not towing) the oil temps do not generally get very high, so I'm perfectly safe. I am not very confident about running a 20 grade in my Nissan VQ though!!!


My truck takes 5 liters of oil, I can't really guess on the oil cooling stuff however.

Does anyone know of a decent oil pressure/ temp gauge I could install to keep an eye on things?

 

[CATERHAM]

First I would get the oil pressure spec's for your engine. There are usually two minimum spec's provided, one at idle and another at some elevated rpm level. Also it's good to know at what OP level the oil pump goes into bypass mode.

With that info' you can choose a oil gauge with the right range. Your can get analog and digital gauges. Go on line or to a local speed shop, there's a huge select to choose from. Even the most inexpensive after market gauges are pretty good.
Also you can get one gauge will provide both oil pressure and oil temps.
Good luck.

In the meantime, if you want to run a 20wt oil now, you could play it safe and simply choose a heavier 20wt than the typical HTHS vis of 2.6cP, something like PU 5W-20 with it's HTHS vis of 2.7cP. Or you could substitute one litre of 5W-30 or 0W-30 which will accomplish the same thing.

 

[Troy]

I'm currently running Redline 5W20 in my 05 corolla which specs for 5W30.

 

[CATERHAM]

Originally Posted By: Troy
I'm currently running Redline 5W20 in my 05 corolla which specs for 5W30.

Good one!
For those that don't know RL 5W-20 with it's HTHS vis of 3.3cP is the heaviest "so-called" 20wt on the planet. In reality it is a mid-grade 30wt oil.
I know a lot of knowledgeable Corvette guys use that oil as a track (racing) oil since it is heavier than factory spec' M1 5W-30 and it contains no VII's so it won't shear.

The virtually shear proof (no VII's) RL 0W-20 with it's HTHS vis' of 2.7cP would be a good choice for the 5W-30 spec'd Corolla.

 

[il_signore97]

Originally Posted By: D189379


My truck takes 5 liters of oil, I can't really guess on the oil cooling stuff however.

Does anyone know of a decent oil pressure/ temp gauge I could install to keep an eye on things?



Well, you're definitely going about this the correct way! To add to Caterham's comments regarding oil gauges for your truck, I know that there are oil filter adapters that you can buy to aid in installing an oil temperature sending unit for a new oil temperature gauge. They make oil temperature gauge installation very easy. I think Greddy has one, as well as other places online (that I somehow can't remember right now). As for an oil pressure gauge, you simply remove your stock oil pressure switch (located near the oil filter), add a T-fitting to the block, and install the factory pressure switch along with your new oil pressure sensor for a new oil pressure gauge.

Honestly, even Canadian Tire has some "decent" oil gauges if you're interested.

 

[cp3]

This thread has got me thinking about this again. Been wondering if I had a thermostat problem in the G5, takes way longer, at least twice as long, than the G6 to warm up. Remembered reading about an oil cooler on some LE5s and confirmed today it is on the 06. So I'm thinking this cooler is at least partly responsible for the extended warm up time but would also make it a good candidate for a 0W20 winter oil.

Right now I have a wheel bearing on the G6 that I have to get done but after that, next car purchase is going to be a Scangauge or some gauges. I am still curious about the vvt though.

Think an email to GM would result in OP specs and pump bypass settings? Or is a shop manual a better start?

 

[cp3]

Caterham, do you recommend both gauges? Better to track changes at a constant oil temp as opposed to coolant temp? I have come up with minimum pressures for both cars but only bypass for the 6. But only an @rpm value, no idle value.

il signore97, is this T-fitting something that I can just pick up, piece together or a fabrication?

Scangauge tells me most cars do not report those values so I'm back to gauges.

 

[il_signore97]

Originally Posted By: cp3
This thread has got me thinking about this again. Been wondering if I had a thermostat problem in the G5, takes way longer, at least twice as long, than the G6 to warm up. Remembered reading about an oil cooler on some LE5s and confirmed today it is on the 06. So I'm thinking this cooler is at least partly responsible for the extended warm up time but would also make it a good candidate for a 0W20 winter oil.

Right now I have a wheel bearing on the G6 that I have to get done but after that, next car purchase is going to be a Scangauge or some gauges. I am still curious about the vvt though.

Think an email to GM would result in OP specs and pump bypass settings? Or is a shop manual a better start?



Okay, if I understand your question correctly... You're wondering what effect the oil cooler on your 2.4L G5 has on warm up?

Basically, here's the deal. It's not meaningful to compare your G6 to your G5 since they have different sized engines. Here's a hypothetical... When comparing 2 engines WITHOUT any oil coolers / heat exchangers, a 4 cylinder will usually take longer to warm up its coolant in the winter months than a V6. This is normal. Sometimes this difference can be huge when you're blasting the heat and only driving on suburban roads (as opposed to the highway).

Now, if you add an oil to coolant heat exchanger into the mix on the 4-cyl engine, the coolant is now responsible for heating the oil as well. Therefore, your coolant temperatures will take even longer to come up since the cold oil is extracting heat from your coolant, as well as your heater (blowing heat into the car). But if you think about it, even though your coolant is taking longer to come up to temperature, your oil is actually warming up faster (you don't have an oil temp gauge, and oil temp can be quite different from coolant temp, so no use in extrapolating).

Your G6 will warm up faster (coolant temp), but the oil may remain colder for a longer period of time or indefinitely. Also, the 2.4L in your G5 has quite a large sump compared to it's engine size.

Now, regarding your question about the 0W20, it's really not related to your coolant temp "issue" on your G5. You can likely put a 0W20 in that engine without any problems at all in the winter, but your coolant will still take a while to warm up (perhaps even longer since the oil will be flowing at a higher rate through the heat exchanger). But either way, this will have no ill effect on anything, and will likely help cold weather starting.

The t-fitting for the oil pressure sender is something you can buy, but you do need to research the type of threads that your stock oil sender switch has and you'd have to buy a t-fitting with the same threads (male on the engine side, female on one of the other ends for the stock switch to screw back into, and another female for your new oil pressure gauge sender to screw into). Also keep in mind that your new pressure gauge sender unit may not have the same threads as your t-fitting (or your stock sender unit), which means some adapter(s) may be necessary. These are all purchasable items, but it may take some trial and error to get it right.

 

[CATERHAM]

Originally Posted By: cp3
Caterham, do you recommend both gauges? Better to track changes at a constant oil temp as opposed to coolant temp? I have come up with minimum pressures for both cars but only bypass for the 6. But only an @rpm value, no idle value.

il signore97, is this T-fitting something that I can just pick up, piece together or a fabrication?

Scangauge tells me most cars do not report those values so I'm back to gauges.

OP is the bottom line as far fine tuning your oil viscosity is concerned. An oil temp' gauge is a nice addition (the coolant temp' is of little value besides it's not calibrated) because it tells you why your OP is what it is.

 

[cp3]

il_signore97,

I see what you are saying. At the time I made the post I wasn't aware that it was an oil to coolant cooler, I thought it was oil to air. What you are saying makes sense, except that previous 4 cylinders I've had were quick to come up to temp but maybe that has more to do with the 6 that I had for comparison at the time.

So, disregarding the warm up time, the G6 may benefit more from tuning the oil as the G5 should at least have more consistent oil temps? It may all be a moot point as the wife isn't too excited about me putting gauges in her car and the G5 is only getting changed twice a year. By the time I get it sorted out, we'll be looking for new cars....lol....we'll see.

I have found that there are also several plugs on the head of the 2.4 so if I do go ahead, there is a place for a temp sender as well. Haven't found a second spot for the G6 yet though. I do have the thread size and apparently AutoMeter makes an adapter but I don't see a T on their site.

Thanx!

 

[cp3]

CATERHAM,

So without a temp gauge, the end of a daily highway run of 30-45 minutes should get the oil about as hot as it's going to get (in my normal usage)? This would be a good time to take readings?

Is there a calculation for HTHS blending like the kinematic viscosity blending calculator? I was able to get HTHS numbers from Petro-Canada for their SN/GF-5 synthetic oils and was curious if calculation would work or if it is more complex than that. I was told they don't publish them as it is more information than the average user is interested in.

 

[cp3]

il_signore, I forgot to say that while maybe mot worded properly, my logic was more that it may be a candidate for 0w20 because of the cooler, not that it may help warm quicker. Again, thinking it was oil to air, cold winter air cooling the oil would probably keep it below summer temps.