thomastl

First - I am a firm believer in Synthetic oil. Have used in my cars for years and love it. Saved an engine one time when the thermostat stopped up and ran extrememly hot. Oil was like new.

As most of you have figured out by now I am new to the Corvette world and have been asking some questions.

I just bought a 1988 Convertible w/ 150000 miles on it that has been running Dino Penzoil all its life (according to the owner I bought it from). After 2500 miles or so on the oil change it still looks like brand new oil.
I would still like to switch to Mobil 1 but have concerns about dislodge of any varnish and possibly stopping up a passage or something.

Have searched the web and not found much other than one posting about Amsoil and they say it does remove some deposits/varnish but the filter should capture.

Anyone have any real word experience w/ changing after high miles.

RWDsmoke

If it has had oil changes every 3000 miles the inside of the motor should still be clean. I've seen 150k mile motors using conventional oil that still looked like new inside. I would do it.

vader86

Run a search HERE, you'll find plenty

Rick86

Were they running Pensoil? I would never run Pensoil in anything, not even my lawnmower. That stuff will turn to sludge too easily. Avoid Quakerstate as well. Those oils tend to be very ashy.

thomastl

The owner was running Pensoil. Like I said - the engine seems very clean.
I thought I did a search before I posted the question but obvously I did not. Found what I was looking for.

Bottom line - your better off but you may (highly likely actually) start finding leaks and have oil blow by the valve seals after changing.

Not sure what I will do. May go w/ the blend for the next oil change and see what that does.

Thanks,
Tony

TR Vert

Synthetic oils have higher levels of detergency. So they may in a sludge coated engine remove enough sludge that is plugging a leak to re-initiate the leak...
However what you describe is a very clean engine.
I would personally not hestitate to switch to a synthetic. Most of us here run Mobil 1 5W30.
KMart had it on sale last week for $4.00/qt. Costco and Sam's Club regularly sell it at $4.35/qt...

Use a K&N filter or a Mobil 1 filter

Davemc1963-87conv

My experience with synthetic oils is similar to others, I don't like using anything else and have been using it for over twenty years.
However, If there is any cr*p in the crankcase, it may become dislodged. Yes the filter may catch it. I have only had one negative experience switching to synthetic and that was on a European version of the Catera and after I switched, one of the hydraulic tappets would tick until it got hot for about a month or so, then it would disapear until next oil change and then do the same, but a different tappet. I came to the conclusion it was a bit of dirt that had been dislodged by the higher detergency of the oil. Like I said, it went away after about a month or so, but it happened every oil change.
Only had one leak though after switching and that was on a seventies car, the seals were probably not at their best.

Wayne88

I can tell you that I bought my '88 with 112K miles, and it always had dino oil, as per receipts from previous owner.
I immediately switched to Mobile 1.
There was no problems at all. I now have 128K miles.
I do change my oil & filter every 3K miles.

Also, all indications are that the previous owner 'babied' the car, never abused.

waterdogvette

if the car made it that well to 150,000 miles with conventional oil i would stick to the same oil...to me any good brand oil is good if you dont abuse your car and dump the oil under 3K miles,..i've seen engines become noisy after switch to syntetic......

OdinsRage

OUTRAGEOUS, old wives tales, you just made yourself look like a big dummy.

You cant even spell pennzoil correct. Pennzoil is one of the best non-synthetics you can buy.

The sludging myth came from the 60's. Dirty running engines, 10w40 oils with tons of VII, oil technology wasnt what it was today. Not to mention lots of people ran non-detergent oils back then,

Castrol, QS, pennzoil, all good oils today, at one point had legions of people thinking they were sludge oils!

www.bobistheoilguy.com

OdinsRage

Mobil 1 is one oil that tends to make engines a bit noisy

But its a fact, that its just the "acoustic" properties of the oil, if you will

It doesnt create more wear or anything, it just transmits more noise!

thomastl

Well I went ahead and switched last night. No sludge or any particles that I could see in the old oil that drained out.
Will see what happens over the next 3000 miles.

Thanks,
Tony

jimcork1

Best of luck Tony. I have done the same thing on my 87. However it only had 55 K on it when I changed. I probably would have continued the Dino oil at 150K and just replaced the engine when needed. I use Mobile 1 in all my cars, but given the 150K success I probably would not have switched. But since you did,, just keep an eye on your gaskets for leaks. You might have a seal gasket leakage issue.

99 Nassau Blue