10w40 oil

[tonttu]

my car owner manual says that only use 5w30 or 10w30 and it says dont use 10w40 or any other grade not recommended.my car is 92 firebird 3.1 112500 miles on it. if i use 10w40,can it damage my engine?my problem is that all synthetic blends here in sweden are 10w40 oils.there is no 5w30 or 10w30 synthetic blend oils available normally.i think some autopartstores can order it from america.but i dont think that its gonna be cheap.

[BobbyZ72]

10w40 is fine...thats all my family has ever used. We have never had a problem

[tonttu]

which one would be better and would provide better protection and have better cleaning agents and additives,shell helix plus 10w40 synthetic blend or castrol synthetic blend gtx5 lightec? :rolleyes:

[hockeyman]

I use Quaker State Synth Blend 10w30. But my climate is nothing like Sweden's! For your sub-zero temps, I'd stick with the 5w30.

['94 Camaro RS]

especially if you live in Sweden. dont use such a heavy grade of oil. its going to make your engine run harder. it will probably do more damage to use 10w40 becuase the oil wont be able to get into all the moving parts creating more friction which in turn will wear down your engine. it will make your oil pump work harder. its not going to give you any more protection then if you used a 5w30. stick with 5w30

[tonttu]

well,temperatures here in sweden are not that cold its now januari and about end of the februari its going to be little warmer.coldest temperature that has been here so far were -7c.(+20f.)and it lasted about a week and then it went back to about +2,+5c.and i dont even drive on winter times just in summer temperatures where i drive in the summer and of course spring and fall is about -2c.to+28c.(about +10fto+80f.i have gm 5w30 oils right now in the engine and i have to say that acceleration and all are little better than mineral 76 10w40 my engine dosnt consume much oil before i change my oils from gm 10w30 to gm 5w30 i drove 10w30 oils about 2500miles and dipstick was still showing full.only problems are that only oils that are here in 5w30 and 10w30 are gm goodwrench dino motor oils.but they are ok,right? :rolleyes: and if using 10w40 oils will damage or put too much stress my engine,i dont use it.i think that i should order mobil or schaeffer synthetic oils from america even that its gonna cost me a lot more,i dont care because only best is good enough [img]tongue.gif[/img] i could also use fullysynthetic oils but my car mileage is 112500 and i havent ever been using fullysynthetic before and i dont want to take that change that it start to leak everywhere because i already have a small leak but i thinks its coming from my faulty oil sensor. [img]graemlins/rofl.gif[/img]

[terminaldegree]

tonttu,

Unless there is an oil consumption issue, an Xw-30 would be preferable to an Xw-40 in your climate.

The only disadvantage with the semi-syn 10w-40 may be decreased fuel mileage.

gm goodwrench probably gets their oil from one of the major US makers - they don't have their own oil blending plant.

With a small leak already, I would use whatever known brand of dino 5w-30 [winter] or 10w-30 [summer] is inexpensive or on sale and change it often. Because 99% of us here are from the U.S. we don't know much at all about the specific oils you are mentioning [they aren't sold here much].

3 questions:
How many miles do you drive in a year?
How much would it cost you to use regular oil and change every 3,000 miles?
How much would it cost you to use semi-synthetic and change every 4,000-5,000 miles?

You can do the math and find the best answer. Both will protect just fine if not equally well [in those intervals].

[CDNFB]

tonttu,

Living here in Canada, I run my car in conditions even more extreme than you. Temperatures from +30 deg C in the summer to -30 deg C in winter. Yup, you heard me, I drive my 99 FB all year round! I have always based by selection of oil viscosities as follows:

1) I start with the Manufactures recommendations. Check your owners manual and you will find a chart that shows the temperature range and oil viscosity to be used.

2) I then consider the amount of wear my engine actually has. How many miles on it, what kind of noises it makes when running (lifters, valves, bottom end, etc...), compression (rings condition), oil consumption from blow by and/or worn rings (do not consider external leakage). If the engine is fairly new and tight, then I stick to the MFGRs recommendations. If old and loose, I go to thicker viscosities.

3) Intended usage also factors in. If you drive the engine at extended high power settings or stress it more than average, like NOS or Forced Induction, also consider thicker viscosities.

My FB just turned 100k miles two days ago, and the oil that I am currently using is Mobil 1 Synthetic 10W/30 year round, which I change every 3000 miles (5000 kms). If I was using mineral based oil, I would use 10W/30 in the summer and 5W/30 in the winter. I do not change to the thinner viscosity 5W/30 in the colder temperatures because the multi grade synthetic oils are more stable over a wider temperature range, stay thin in cold and thick in hot (in comparison to mineral oil).

As this engine ages, I will be using synthetic 10W/40 in the summer and synthetic 10W/30 in the winter.

I did this with my '87 3.8 l oldsmobile Delta 88 and after 375,000 kms the engine still ran perfect!

DZ

[tonttu]

i drive about 9500miles/year.(14400km)i dont really care how much oil costs are,i will put only the best oils in my car,no matter how much is gonna cost. like mobil,schaeffer,,,i change my gm oils every 3000miles and i use ac delco duraguard (blue) pf52 filter.purolator could be better,maybe i try one of those someday.but i heard it could make oil pressure just a littlebit higher than ac delco.those gm dino oils that i use:bottle says, it meet or exceeds all general motors specifications for buick,cadillac,chevrolet,chevy truck,gmc truck,oldsmobile and pontiac also,it is api certified for gasoline engines sae 5w30 sl/sj energy conserving.so it should be good quality and all,right?but i would like to use synthetic blend,like mobil drive clean 7500 or shcaeffer supreme 7000 5w30.because they clean engine better than dino oils,at least i think they do.my pontiac dosnt consume much oil,i drove last time gm dino oil 10w30 about 4000km/2500miles and it only take less than 1/2 quart new oil to bring the oil level full again.i did try 10w40 oil before,it was 76 dino oil.but my engine was little slower with that 10w40 oil and i change those after one week gm goodwrench 10w30 oil.now i have gm 5w30 oil. 0w30,5w30 and 10w30,they have all same thickness at operating temperatures.i found that information www.bobistheoilguy.com i think i should try order mobil synthetic blend 5w30 somehow from america. :rolleyes:

[CDNFB]

Sorry, this post is a little late and longwinded, but here goes.....

Given what you have told me about you engine and it's oil consumption, if it was my car, I would be using 10w30 synthetic. I don't mean to change your mind,it is just my opinion.

Although the oilguy website is a great source of information, I believe the viscosity comparison chart does not tell the whole story. I believe those charts are for straight or single grade oils and multigrade oils act a little differently at temperatures above 100 deg C. Comparing viscosity change between different multigrade oils at temps elevated above 100 deg C you would find that they are not the same. For example, 5W30 will be thinner than 10W30 at say 160 deg C.

Although our engines do operate at a coolant temperature of approx 100 deg C (212 deg F). the oil temp in the area of the piston/rings/cylinders are considerably higher than that. Thus the oil in that localized area will hotter and thus thinner than oil found elsewhere in the engine. How thin will be determined by your oil viscosity selection.

In my own experience this is proved by my selection of oil for my 72' Pontiac Formula 400. In this car (before I started it's restoration) I would use 5W30 in the winter and 10W30 in the summer. But during the spring when it was warmer out, my oil consumption would increase, to the point where I would find oil in the Air Filter housing (from excessive blow by). Yet this conditon would be reduced dramatically when I changed to the 10W30. Yet they're both 30 weight oil at 100 deg C right?

All oil, as long as it has the API certification will meet or exceed MFGRs recommendations. It's just a question of what grade should you use. The 5W/30 oil became the oil of choice for most manufactures in the 80's when they were (and still are) trying to maximize fuel efficiency. But even back then there were cases where this couldn't be applied. The recommended oil for my 87 3.8 l in my Oldsmobile was 5/30. But for my Father-in-laws 87 Buick GN with the 3.8 l it is 10W/30. Although both are basically the same buick V6 it was because the 3.8 in his buick is turbocharged and running 250 hp and needs the greater protection that the 10W30 offers. This is also why the 3.8 in our FireBirds (rated at 200 hp) also requires 10W30.

It's surprising that there is no manufacturer in Europe or Scandinavia that offers 5W30 or 10W30! In North America there used to be only a few manufactures of synthetic motor oil, Mobil, Amsoil, and Redstripe. But now it seams that everyone is now getting in on the action, which is great because prices are becomming more reasonable. Good luck in your search.

DZ