15/40w diesel engine in a car

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sirgerman

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I just was told that
"Use any xW-40 oil and you will experience short engine life unless it is one of the 5w-40 full synthetics"
is that true ?

the car in questions is a Saturn sl2 1.9
 
Im not 100 percent sure but i think there are some saturns that have very small oil holes to lubricate the timing chain. Not sure if this is one of them but something to look into.
 
I am going to run it in my 99 SL2 this summer. I am going to add a quart of 5-20 to make it a little thinner. I believe Eljefino uses it in his Saturn's. He is pretty Saturn knowledable. I got the 15w40 idea from him....

I ran Rotella 10w30 this summer. I topped off with Rotella 15w40 a gallon or so.
 
Originally Posted By: sirgerman
I just was told that
"Use any xW-40 oil and you will experience short engine life unless it is one of the 5w-40 full synthetics"
is that true ?

the car in questions is a Saturn sl2 1.9


Whomever told you that has no clue what they are talking about. You can go one grade thicker with no real ill effects,other than perhaps less fuel economy. However on a higher mile motor that consumes some oil it will slow down the consumption. What does the engine originally spec. I wouldnt go using a hdeo unless really needed. Does a Saturn trash oil pretty fast.
Use it but thin it out with some pyb 5w-20 or pint of mmo.
Stick to the spec unless it's using some oil between changes,then maybe go a grade thicker but if you aren't having any problems why change. Jmo
 
Originally Posted By: Clevy
You can go one grade thicker with no real ill effects,other than perhaps less fuel economy.


Sometimes you'll even get better fuel economy with the thicker
grade if it lubricates better. I've had that experience before.
 
The car calls for 5w30. I would try one of the branded high mileage versions of 5/30. I would be concerned about cold starts with the 15w/40. You already suspect small holes to oil the chain why compound the problem at cold temps trying to push thicker oil through small holes.

No oil or additive is going to stop your consumption maybe it will slow it a little but, at 150,000 miles that engine is consuming or leaking (check all your gaskets and seals) 1 qt. that's about $10/month to top off. that's a hole lot cheaper than rebuilding or replacing your engine. Stay close to what is recommended by the manufacturer.

Do you use synthetic now? even a cheap synthetic like Peak, Walmart or PepBoys will give you improved cold start features and not break the bank.
 
Originally Posted By: Merkava_4
Originally Posted By: Clevy
You can go one grade thicker with no real ill effects,other than perhaps less fuel economy.


Sometimes you'll even get better fuel economy with the thicker
grade if it lubricates better. I've had that experience before.


Strange that you mention that as I have noticed that before as well.
 
Originally Posted By: sirgerman
I just was told that
"Use any xW-40 oil and you will experience short engine life unless it is one of the 5w-40 full synthetics"
is that true ?

the car in questions is a Saturn sl2 1.9


I've run 15W40 in my Neon(5W30 spec'd) for last 4 summers now. I do the odd track day and lots of autocross with it so I wanted an oil that's a bit better for thrashing the sheet out of the old motor. The only thing you have to watch is not red lining the motor when the oil/motor isn't hot. Oil can build up in the valve cover as it won't drain down as fast as its pumped in, if your near redline for a while. I've only sucked oil in through the PCV system once on a banked oval when the car cooled to much between runs.
Anyways for normal highway driving in warm/hot weather it won't hurt a thing. If you just do short city trips you might want to use a 10W30 HDEO.
 
Originally Posted By: A_Harman
Try using a High-Mileage 5w30 and give it some time to work before switching to 15w40.

That's the best advise.
Additionally I would never use a 15w40; with it's low VI it is almost a straight 40wt oil.
 
The 15w40 is some mighty thick stuff, if you must then try a 10w40 first. There are some that are just as thick as the HDEO's at operating temp, but they will flow better when cold than a 15w40 will.

I like the idea of trying a thick 30 weight first even better, a HM version PCMO like Quaker State or an HDEO like Rotella.
 
Originally Posted By: coffee
Originally Posted By: Merkava_4
Originally Posted By: Clevy
You can go one grade thicker with no real ill effects,other than perhaps less fuel economy.


Sometimes you'll even get better fuel economy with the thicker
grade if it lubricates better. I've had that experience before.


Strange that you mention that as I have noticed that before as well.


Same here. I get the best mileage with a 50 weight.
 
Originally Posted By: aquariuscsm
Originally Posted By: coffee
Originally Posted By: Merkava_4
Originally Posted By: Clevy
You can go one grade thicker with no real ill effects,other than perhaps less fuel economy.


Sometimes you'll even get better fuel economy with the thicker
grade if it lubricates better. I've had that experience before.


Strange that you mention that as I have noticed that before as well.


Same here. I get the best mileage with a 50 weight.

Utter nonsense.
 
Makes perfect sense. Thicker oil film,greater barrier between moving parts,less friction/more cushioning via thicker oil film. BUT,I`ve only noticed the better mileage on extended high speed drives. Around town/stop and go,mileage seems to stay the same whether I`m using a 10W40 or 20W50.
 
On oil-burning cars, using a thicker oil can increase mileage. The thicker oil reduces the amount of oil in the combustion chamber and can help improve compression.
 
Sorry but it's utter nonsense and seriously I thick you know it.
With all the variables that affect fuel economy, an oil's viscosity is just one. The difference in fuel economy between a 5w30 and a 5W-50 (the low VI 15w40 could be worse) is about 4%. That's just over 1 mpg on a car that averages 30 mpg. Can one accurately measure that themselves? I know I can't.
 
Originally Posted By: SS1970chrysler
On oil-burning cars, using a thicker oil can increase mileage. The thicker oil reduces the amount of oil in the combustion chamber and can help improve compression.

That's assuming the cause of the higher oil consumption is badly worn compression rings and/or cylinder bores which usually is not the case.
More often it's simply worn valve guide seals and/or clogged oil control rings.
 
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