Synthetic Question

[90Q45blue]

Hi Guys,

As my sig says my car is rapidly approaching 250k. I have never used synthetic oil in the car but am considering making the switch. My worry is that my mechanic says that he has seen some higher mileage cars switch to synthetic and then begin to have oil leaks. Is this something I should be worrying about? If so, is there anything I can do to make sure it won't leak? or should I stick with conventional oil?

Same question for transmission but it was rebuilt 8,000 miles ago.

Thanks everyone,

Nick

p.s. if i do go synthetic I'll probably use Mobil 1 15w50 or 20w50 as recommended by Fred.

[AZhitman]

Search for "Synthetic" and "leaks"... I can't recall the thread, but this was discussed at length.

My recollection was that it is a harmless (and actually helpful) change - Just DON'T switch back to conventional (IIRC).

[90Q45blue]

Thanks AZ,

Don't worry. Once you go synthetic you'll never go back...or somethign like that.

Nick

[greg_atlanta]

Some people (including me) have had problems with the new Mobil 1 formulation. Created some strange valve clatter noises I didn't notice before.

I've switched around between Mobil 1 and Valvoline synthetic but have mostly used Valvoline Durablend (conventional base oil with more additives).

I will not use full synthetic anymore since at 186K miles ('92 Q) the oil change frequency is a lot more important than the oil type.

$2.50 a quart for Durablend is about what T-3 or dealer charges for conventional oil, so I usually bring my own.

[90Q45blue]

When it comes to oil, price doesn't matter TOO much to me. I just want to use something that will help my car run better, smoother, longer and be good for it. As long as switching to synthetic won't hurt the car or cause leaks, it's something I'll definitely do. As far as what brand/weight, I'm going with our oil guru Fred's advice.

nick

[AZhitman]

Good call.

[Q45tech]

At 250k lots of damage has been done, don't think synthetic will do you much good as the bearings are probably pretty thin by now.

What is your hot idle [675 rpm in drive] oil pressure that will tell you the proper thicknesss grade [viscosity 10w"X"]..........mine having used 10w30 Mobil 1 for the past 200,000 miles [250,100 total] still meets/slightly exceeds minimum spec with brand new oil and factory filter.

As its 250k present it received an oil change at 300 miles and currently has 600 miles which will be changed again at 1,000 miles........couple of quicky conventional Vavoline's to clean up things.