Engine oil, old car: synthetic or not, change weight?

[jobin]

Am using a bit of oil after 3k km and will need to top up before the month is out.

Now have ordinary motor oil but some shops sell only synthetic or part synthetic oil. Can i mix the real oil with synthetic?

Now have 10/30. Stay with that weight or go heavier, say straight 30 even 40 weight, if available.

Engine 1500cc, car 18 yrs old and peppy enough for me.

[sotsira]

Not worth topping up with synthetic if you only have ordinary oil in the engine.

If you want to use synthetic it's best to change all the oil and filter.

The grade you use should be the one recommended for your specific engine

so check your owners manual or ask the main dealer of your car model.

[pgrahmm]

Putting synthetic in an old engine is a risky business.....The molecules are smaller in Synth and will bypass seals as well as rings if worn.....

Take a good sized handful of coins and put them down on the table in front of you - that's what organic oil looks like....The molecules are all different sized creating a natural barrier to help seal as well as cool/clean/lubricate....

Now remove all the coins except for the satangs - now you're looking at Synth oil molecular constuction....Great if a new engine - unwise if an old engine - regardless of what they try and sell you.....

NOTE....You cannot start and operate a brand new engine on Synth oil....It will lunch/hydrauloc the motor - never seals and bypasses everything.....I've watched it happen.....Has to be run with a break in organic oil first for a short duration......

One liter in 3000k isn't that bad....Try a 15w40 or 20w50 if it bothers you (lower viscosity always remains the same - just covers/runs from the heat/hot spots at the stated rate of the upper viscosity index)

[JAS21]

Putting synthetic in an old engine is a risky business.....The molecules are smaller in Synth and will bypass seals as well as rings if worn.....

Take a good sized handful of coins and put them down on the table in front of you - that's what organic oil looks like....The molecules are all different sized creating a natural barrier to help seal as well as cool/clean/lubricate....

Now remove all the coins except for the satangs - now you're looking at Synth oil molecular constuction....Great if a new engine - unwise if an old engine - regardless of what they try and sell you.....

NOTE....You cannot start and operate a brand new engine on Synth oil....It will lunch/hydrauloc the motor - never seals and bypasses everything.....I've watched it happen.....Has to be run with a break in organic oil first for a short duration......

One liter in 3000k isn't that bad....Try a 15w40 or 20w50 if it bothers you (lower viscosity always remains the same - just covers/runs from the heat/hot spots at the stated rate of the upper viscosity index)

Re your NOTE ... I guess that's why new vehicles supplied with Fully Synthetic ... eg Ford ...may use some oil in the first couple of thousand kms ...Ford advise usage may be greater during this period.

I wonder if it's advisable to replace oil and filter at 1000kms

[Pomthai]

Personally, I would forget multi grade oil. In an engine as described by the OP I'd stick straight SAE40 weight mineral oil into it & and be done with it. Also an engine like that perhaps has a crank case breather with a gauze wire mesh filter in it. This might be blocked, causing more oil or vapor to pass the rings. Find the crank case breather pipes / filters etc and clean all. You might find the oil consumption drops - but the SAE40 should help a bit in that department too.

[VocalNeal]

Is the car actually "burning" oil or and you just losing a very small amount? If very small or on the high side of normal changing to anything with a 50 (if you can find it) in the name will probably sort that out. If you are burning oil, ie detectable from the tail pipe we have to ascertain where it is leaking from. It could be simply one sticky piston ring or worn valve seals. If you have a black spot on the driveway it will be the crank seals.

After changing to somethingf with 50 in the name have a wander around and see if you can find a can of Wynns or STP Engine Stop Leak or the like.

You cay your source only has synthetic or semi-synthetic which is a waste of money as it is niether fish nor foul) then try Tesco or Makro.

Lots of stuff on the oracle of instant anwers , like below.

HOW TO REDUCE OIL CONSUMPTION IN HIGH MILEAGE ENGINES

There are no "miracle" engine treatments or pills that will stop oil burning or magically restore worn cylinders and rings. But some crankcase additives can slow oil burning, although they won't stop it entirely.

There are also "high mileage" motor oils that are specially formulated with extra additives to slow oil consumption. Switching to a high mileage oil the next time you chaage oil may help reduce oil leaks and burning.

Switching to a heavier viscosity motor oil may also help reduce oil consumption. Try moving up one viscosity grade the next time you change oil. If your engine currently uses a 5W-20, switch to a 5W-30 or maybe a 10E030 oil. If you drive an older vehicle that uses 10W-30 oil, try a 10W-40 or possibly a 15W-40 or 20W-40 (but only for warm weather driving because 15W-40 and 20W-40 may be too thick for cold weather starting and lubrication).

If your engine is using oil because of a leak, the leak must be fixed to stop the loss of oil. Sometimes all that's necessary is to retighten the valve cover or pan gasket mounting bolts because they can loosen over time. But if the gaskets are crushed and have lost their elasticity, you will need new gaskets. Valve cover, timing cover and oil pan gaskets are usually not too difficult to replace, but leaky crankshaft end seals can require a lot of disassembly (particularly the rear main crankshaft oil seal).

One alternative to replacing a leaky gasket or seal is to add a bottle of "seal conditioner" to the crankcase, or to switch to a "high mileage" motor oil. The seal conditioner additives in these products soak into old gaskets and seals and cause them to swell slightly. Hopefully, this will slow or seal the leak.

If the engine is using oil because of worn valve guides or valve guide seals, it is possible to replace just the valve guide seals without having to remove the cylinder heads or overhaul the engine. New valve guide seals can drastically reduce oil consumption. I have seen older high mileage engines go from using a quart of oil every 500 miles to using no oil between oil changes (3000 miles) by simply replacing the valve guide seals!

Don't give up on the old girl just yet!

[pgrahmm]

Is the car actually "burning" oil or and you just losing a very small amount? If very small or on the high side of normal changing to anything with a 50 (if you can find it) in the name will probably sort that out. If you are burning oil, ie detectable from the tail pipe we have to ascertain where it is leaking from. It could be simply one sticky piston ring or worn valve seals. If you have a black spot on the driveway it will be the crank seals.

After changing to somethingf with 50 in the name have a wander around and see if you can find a can of Wynns or STP Engine Stop Leak or the like.

You cay your source only has synthetic or semi-synthetic which is a waste of money as it is niether fish nor foul) then try Tesco or Makro.

Lots of stuff on the oracle of instant anwers , like below.

HOW TO REDUCE OIL CONSUMPTION IN HIGH MILEAGE ENGINES

There are no "miracle" engine treatments or pills that will stop oil burning or magically restore worn cylinders and rings. But some crankcase additives can slow oil burning, although they won't stop it entirely.

There are also "high mileage" motor oils that are specially formulated with extra additives to slow oil consumption. Switching to a high mileage oil the next time you chaage oil may help reduce oil leaks and burning.

Switching to a heavier viscosity motor oil may also help reduce oil consumption. Try moving up one viscosity grade the next time you change oil. If your engine currently uses a 5W-20, switch to a 5W-30 or maybe a 10E030 oil. If you drive an older vehicle that uses 10W-30 oil, try a 10W-40 or possibly a 15W-40 or 20W-40 (but only for warm weather driving because 15W-40 and 20W-40 may be too thick for cold weather starting and lubrication).

If your engine is using oil because of a leak, the leak must be fixed to stop the loss of oil. Sometimes all that's necessary is to retighten the valve cover or pan gasket mounting bolts because they can loosen over time. But if the gaskets are crushed and have lost their elasticity, you will need new gaskets. Valve cover, timing cover and oil pan gaskets are usually not too difficult to replace, but leaky crankshaft end seals can require a lot of disassembly (particularly the rear main crankshaft oil seal).

One alternative to replacing a leaky gasket or seal is to add a bottle of "seal conditioner" to the crankcase, or to switch to a "high mileage" motor oil. The seal conditioner additives in these products soak into old gaskets and seals and cause them to swell slightly. Hopefully, this will slow or seal the leak.

If the engine is using oil because of worn valve guides or valve guide seals, it is possible to replace just the valve guide seals without having to remove the cylinder heads or overhaul the engine. New valve guide seals can drastically reduce oil consumption. I have seen older high mileage engines go from using a quart of oil every 500 miles to using no oil between oil changes (3000 miles) by simply replacing the valve guide seals!

Don't give up on the old girl just yet!

Some incorrect advice above....1- the upper viscosity rating does not mean a higher viscosity/thicker oil so won't change the usage 2- Seal expanders/thickeners ruin the seals then it's rebuild/replace time....probably more but have to run an errand - wife just came back to the car....