What oil to use with an engine that is slowly wasting away?

I started taking my 1994 Voyager to a dealer a few years ago. Since
then, I have developed a coolant leak in the engine. Maybe a head
gasket, maybe a cracked block, maybe whatever - it failed the pressure
check.

Now with a car that has over 200,000 miles, not kilometers but miles,
this could be expected plus its dozen years of age.

But, but all through its lifespan it had 10W-30.

The dealer uses 5W-30, specifically:
Conoco Super All Season Synthetic Blend, 5W-30, Bar Code: 0 64229 09712
7, CB09712-02, Rev 8/4. [It's possible that the bulk that the dealer
uses in large containers is not exactly this but it's in the ballpark.
This is the quart size which may or may not be identical. Difficult to
get really good information out of the Five Star Dealer but they try,
kind of.]

One size oil fits all. Every car gets this oil. BUT the dealer services
relatively new cars, not my 12 year old beast. They are catering to the
shiny, new, and expensive cars. So I doubt they decided on this 5W-30
for old cars with much thought. After all, how much is an old Chrysler
worth after 12 years? Not much liability here, sadly.

At first I was not happy. If the car lasted 10 years on 10W-30 why
change now? And why not inform me first? I asked otherwise I would have
never known.

It's summer now and getting into almost the 90's soon.

Should I go back to 10W-30 and dinosaur instead of this 5W-30
semi-synthetic? Or just worry about some other world-shaking event?

Is it all a coincidence? I would think that a lighter semi-synthetic
would make the engine work less and less likely to blow a head gasket.

 

At operating temperature there is virtually no difference in viscosity
between the 5W and 10W-30. So regardless of the fact that the weather is
getting warmer, it really doesn't matter which one you use.

The headgasket/leak thing would not be related to the type of oil used.

Phil

 

Yes and no, if I may kind of disagree.

In regards to the viscosity, the weights would not affect the head
gasket.

But, in regards to the additives, quite possibly so.

Why? A full synthetic could get some of the varnish, for example, and
that might allow the head gasket to leak? Is that not a possibility?

A semi-synthetic might also do the same thing when you have a dummy
like me who had to top off the oil. Since the dealer did not have
quarts of the semi-synthetic they had used, I had to buy another brand
of semi-synthetic.

It is quite possible, even likely, that the different brands of
semi-synthetic got together and nailed the sludge or varnish keeping
the engine from leaking.

So that is my conclusion. Part stupidity on my part for not knowing
better. Part the dealer could not be bothered to sell quarts of the oil
that the Five Star Chrysler Dealer used in bulk to do oil changes. And
this oil was not available in any of the stores. It was a
Conoco-Phillips Synthetic Blend. At least not in any of the stores that
I go to.

 

I wouldn't worry about the viscosity, but I would worry about the additive
package in new SM spec oil coming out. YOu can get a lot more lubrication
out of older style oils if you can find them. You can always use Delo or
Rotella (18-wheeler oil) if you can find those.

 

Uh oh, more lubrication in the older oils, like SL or previous? Why is
that? Have the priorities changed? So Rotella is used in the big rigs
then?

I was quite worried not about the viscosities but the various additives
when mixed together doing something unplanned. I could not purchase
single quarts of the semi-synthetics [Conoco-Phillips] the dealer uses
to top off my oil, so used other brands from auto stores. From what I
learned, none of this could attack a head gasket, if that is my
problem. So what does it attack, assuming it does, the additives from
different semi-synthetics if mixed together?

I'll take it easy. And maybe try a sealer like GM's almond shells or
Nanotechnology but I will be reluctant since I'm not wanting to make a
bad problem worse.

 

Your imagination is running a bit too freely here.

This is motor oil - not a solvent or cleaner. You aren't going to remove
any varnish with a couple of changes of semi-synthetic oil. You probably
won't ever remove any varnish for that matter. In a *few* cases, people
have reported mild engine cleaning after using something like Mobil 1 or
Redline for a couple of years or 50,000+ miles.

A head gasket leak will not be related to choice of oil.

Phil

 

The performance specs on the SM oils are actually better than the SL oils.

You've probably read about reduced levels of phosphorous based additives
in the SM oils. That is being compensated for with newer additive
chemistries.

Phil

 

Leaking seals is what I heard with those wanting to put in a pure
synthetic oil in engines with extreme miles, like mine, 200,000. Since
I am not going to put in any Mobil 1, this is not a variable to put
into the equation.

Now something is leaking, that is for sure. Coolant is being used
around 1 gallon per month or 1 gallon per 800 to 1000 miles. Not too
bad. What is leaking? Water pump and either the head gasket or a crack
in the block or the head.

I suspect the leaking coolant got the oxygen sensor. Maybe a
coincidence.

Now what to do?

Nothing? Or see about getting GM's crushed walnut shells or Cooling
System Sealant Tablets or maybe Nanotechnology Permanent Head Gasket
and Block Repair sealant.

A miracle for $20?

Or ask who is willing to throw in a used engine when the car goes.

 

Did you look in the owners manual? I am pretty sure it calls for 5W-30

I use 5W 30 in my 1995 and 1994 T&C's with no problems.

Ted

 

Now that definitely is true. The seals that are affected are the
synthetic "rubber" oil seals throughout the engine. But the head gasket
does not have a rubber.

Wow. That's pretty heavy coolant loss. If it's the water pump leaking
you should be able see coolant at the weep hole. If coolant is leaking
through the head gasket into the crankcase, then you should see milky
sludge inside the oil filler cap, and see the oil level rising on the
dip stick. If your transmission oil cooler is built into the rad and
the leak is there, you should rising fluid level on the trans dip stick,
and see milky sludge there. If the coolant leak is through a manifold
gasket or head gasket, into a combustion chamber, you should see a white
plume out the tail pipe and spark plug deposits/coloration in the
affected cylinder(s)

All O2 sensors I've seen are external to the engine. Usually in the
exhaust manifold or further down the exhaust system.

Determining where the coolant leak is should be the first priority.

 

Yes I did. And it specifies 5W-30 but up to 100F, from 0F to 100F.
And it has 10W-30 from 32F to above 100F.
That's what I recall. It would seem for a wide margin of safety to use
5W-30 in the winter and 10W-30 in the summer.