Switching to synthetic oil

[_HighVoltage_]

I know there is a lot written about the subject, but last night I heard something (quite possibly a myth) that I couldn't believe.

A friend told me about a guy who has always ran his Cavalier with dino oil, then all of a sudden switched to synthetic and ruined his engine. When they drained the synthetic out of the engine it had "silverish" color and had engine bits in it.
So he suggested that the change from conventional to synthetic should be gradual. First make an oil change with 50/50 conventional and synthetic. On the next change put full synthetic.

Is this true, or is it another myth? (I suggested it happened because it was a Cavalier )

I have to change my oil soon, and I don't know what has been used so far. I'm guessing it is conventional. I want to put full synthetic Mobil 1, but the engine has 153k miles. Do I risk ruining the engine, apart from eventually having some oil leaks?


(Engine condition: 153k miles, in 1,300 miles it burnt 1/4 quart of oil, has somewhat noisy hydraulic lifter, NO gasket problems - coolant keeps its level and color.)

[JipJopJones]

Some people beleive (I'm on the fence on this one) that changing to synthetic in a high mileage car will clean out all the gunk that was holding up the compresstion and keeping the seals tight, thus leading to massive engine failure.

[GRtak]

Synthetic oil won't ruin an engine as long as it wasn't neglected badly. If it was neglected(infrequent oil changes, full of gunk), it could losen up a ton of gunk at once. The only problem I've encountered is an oil leak(mostly annoying).

[Punisher Bass]

Before my Buick hit 100k, it always got regular Valvoline durablend. After it hit 100k I switched to their full synthetic and have had zero problems for the last 30k.

[_HighVoltage_]

I'll risk it - I'll switch to Mobil 1 Full Synthetic. The biggest possible problem is a leak from the Rear Main Seal...
Keep your fingers crossed that no leaks occur.

[73GMCSprint]

The only thing I would suggest is watch your oil color on the first change, and probably change the oil and filter again fairly soon after the first time. With the first change after I switched my wife's car the synthetic cleaned enough crud out of the engine that it went completely black in under 1000 miles, vs. the ~5000 mile intervals it's had between changes since.

[Punisher Bass]

Originally Posted by _HighVoltage_

I'll risk it - I'll switch to Mobil 1 Full Synthetic. The biggest possible problem is a leak from the Rear Main Seal...
Keep your fingers crossed that no leaks occur.

You can buy addatives that are made specifically for fixing a leaky rear main seal. The name escapes me but I'd check out your local auto parts store and see what they say. I just saw one on tv a few weeks ago but the name totally escapes me.

[prizrak]

Originally Posted by Punisher Bass

Before my Buick hit 100k, it always got regular Valvoline durablend. After it hit 100k I switched to their full synthetic and have had zero problems for the last 30k.

You ran a boosted car with conventional oil? I thought all FI engines needed synthetic, or maybe it's just turbos?

[tigger]

The only problem I've ever had when switching from dinosaur oil to synthetic is oil leaks (and I'm too lazy to fix them until they get bad).

[_HighVoltage_]

@prizrak - Yes, generally Turbo cars require Synthetic oil.

Originally Posted by Punisher Bass

You can buy addatives that are made specifically for fixing a leaky rear main seal. The name escapes me but I'd check out your local auto parts store and see what they say. I just saw one on tv a few weeks ago but the name totally escapes me.

That's one of the biggest mistakes people do. Those additives are only partial fixes - they work for few thousand miles, but after that you are back to where you started and even worse! The way they work is that they "inflate" the rubber gaskets and seals in the engine. ALL of them. So they fit better and fill in any gaps. But after a few thousand miles, the rubber swells down, and now you have leaks not only from the RMS, but from all of your seals.

[syncview]

Try the oil, if something happens, just overhaul your engine :p

[adaptech]

Originally Posted by _HighVoltage_

A friend told me about a guy who has always ran his Cavalier with dino oil, then all of a sudden switched to synthetic and ruined his engine. When they drained the synthetic out of the engine it had "silverish" color and had engine bits in it.

If the oil is a "silverish" color it means there is very much coolant mixed with the oil. For that to happen the headgasket needs to be very much gone or the block or head has big cracks in it. And that wont happen just because you change from mineral to synthetic oil. That engine had to be barely hanging together before he changed the oil.

[Punisher Bass]

Originally Posted by prizrak

You ran a boosted car with conventional oil? I thought all FI engines needed synthetic, or maybe it's just turbos?

I've never heard of an engine requiring synthetic because of a turbo or supercharger. My Eaton has it's own separate oiling system with it's own special blend of oil. I know at least some turbos get their lubrication from engine oil pumped through it, so I guess synthetic would help in that case.

Originally Posted by _HighVoltage_

@prizrak - Yes, generally Turbo cars require Synthetic oil.



That's one of the biggest mistakes people do. Those additives are only partial fixes - they work for few thousand miles, but after that you are back to where you started and even worse! The way they work is that they "inflate" the rubber gaskets and seals in the engine. ALL of them. So they fit better and fill in any gaps. But after a few thousand miles, the rubber swells down, and now you have leaks not only from the RMS, but from all of your seals.

Well it's either a few bucks for the addative every couple thousand miles, or you pay the price of replacing the seal which could be a simple as removing the main cap or as complex as removing the crankshaft.

When I was bringing our old Taurus back to life after it sat motionless for several years, it had a leaky freeze plug. I had two options to fix it, either spend $800 for the engine to be pulled so the plugs could be replaced or spend $5 on these little tablets you add to the coolant which would seal up the leak. What option do you think I went with?

That leak did not return for the rest of the cars life.

[argatoga]

Originally Posted by Punisher Bass

That leak did not return for the rest of the cars life.

Well the car didn't have too long of a life after you fixed it.

[Punisher Bass]

Yeah yeah I know, don't remind me. BUT at least its death was caused by outside forces and not something internal.

[_HighVoltage_]

But those additives only work the first 2-3 times you put them in. After that, the rubber seals are completely ruined.

A RMS for my Volvo would cost somewhere in the ballpark of $700 in labor. It requires lifting the whole engine and transmission out of the car, so they can be separated. Annoyingly enough, that's a common problem with the 850. *knock on wood* Mine seems to be ok.

[prizrak]

I've never heard of an engine requiring synthetic because of a turbo or supercharger. My Eaton has it's own separate oiling system with it's own special blend of oil. I know at least some turbos get their lubrication from engine oil pumped through it, so I guess synthetic would help in that case.

Every turbo I have ever seen uses an oil line from the engine. I know my car for example can ONLY run synthetic and nothing else.

[tigger]

Originally Posted by adaptech

If the oil is a "silverish" color it means there is very much coolant mixed with the oil.

Every time I've had an engine eat a rod or bearing, the oil has been filled with minuscule metal shavings making it 'silverish' in color. When I've dealt with cracked cylinder heads or bad head gaskets, and there's been substantial mixing of oil and coolant, it all comes out looking something like a chocolate shake. I'm not a mechanic or anything, but that's my personal experience.

[Nabster]

Originally Posted by prizrak

Every turbo I have ever seen uses an oil line from the engine. I know my car for example can ONLY run synthetic and nothing else.

That doesn't surprise me, but that said, the super on my Grand Prix has its own internal supply of special oil. It's a really lightweight oil (80 weight gear oil I think, it's been a while since I had to change it). Not a pleasant smelling stuff.

[Punisher Bass]

Originally Posted by Nabster

That doesn't surprise me, but that said, the super on my Grand Prix has its own internal supply of special oil. It's a really lightweight oil (80 weight gear oil I think, it's been a while since I had to change it). Not a pleasant smelling stuff.

I was told that when I rebuilt my supercharger, and while it does smell bad, I've smelled far far worse.