Yow! Using Oil!

[MustangPaul]

Hi all--

Lately, my 66 has been using oil--about a quart every 2000 or so. Before this summer, it was tight except for some minor seeps.

On my way to a show in Biloxi, I had some extended highway time at about 75 mph for almost 2 hours. (The car is mostly an around town machine with occasional pleasure drives in the country.) When I got back from MS, the car was down about 1.5 quarts. I panicked and started keeping records--usually 2-3 times weekly- of my oil levels.

I've noticed that when the car is used around town, the oil use is almost nil. When it is on the highway, even at a steady speed of no more than 70, the oil use goes way up. Case in point. I put about 100 miles on the car today in the country and back on interstate and my oil level was down 1/4 of a quart. That's not good. Yet, at about 100 in town miles, the oil level holds steady or drops just a smidge.

There aren't any leaks that show up in my catch pans under the car or in the same parking place I always park in, so I assume it is using.

Ideas?

What can I do/have done to narrow the problem, short of tearing down the engine (which may have to be done.)

The engine was rebuilt about 19 years ago, but for about 10 of those years, it was an occasional driver. The rest of the time, it is a daily.

What puzzles me is the incresed usage at higher speeds. What could cause that? Cracked ring? Would a compression test show that?

I'm usually clueless, but I'm really stumped now. Can you give me some ideas?

Thanks!

--Paul

PS I'm running Havoline 10/40, if that makes a difference. Oil pressure is good, but drops a tad with the heat and the AC on.

 

[6Stang7]

Well, I would assume that while you're on the freeway, you are running at a higher rpm for a longer time then around town. That being said, I would guess that either your rings are not holding, that your valve seals are leaking, or a combination of both. You could also have an oil leak from a gasket somewhere. I would suggest that you buy some oil dye, so that you can trace a leak back. The oil pressure dropping when the AC on is normal. The engine will run hotter reducing the viscosity of the oil.

 

[MustangPaul]

How does one diagnose a leaking ring or valve seal/guide short of tearing down the engine? (Or invoking your Superman-like power of X-Ray Vision?)

 

[Ozsum2]

How does one diagnose a leaking ring or valve seal/guide short of tearing down the engine? (Or invoking your Superman-like power of X-Ray Vision?)

Compression check for rings and vacumm check for valves and other internals.

 

[Max Power]

While putting around town, quite often fuel wash from the cylinder walls will make its way into the crankcase, masking oil consumption and replacing burnt oil with gas. Then when you go for extended highway trips, the heat generated in the crankcase makes the gas in the oil evaporate or burn off, making it seem like you are only using oil on freeway trips. Quite often, you are using oil at a steady rate and it is being hidden by your driving habits.

Using a quart every 2000 miles is nothing to worry about, and even new cars won't get any engine work warrantied at any consumption of a quart over 1000 miles. When I worked at GM dealers 20 years ago, the use rate had to be a quart in under 750 miles before the factory would pay for it.

At any rate, if oil isn't fouling your plugs or smoking out the tailpipe, why spend a couple grand just to save a quart here and there. Many new engines use oil at a rate faster than that anyway.

My opinion is that you would be flushing your money away. Send me the 2 grand and I will send you a quart of oil whenever you need one!

 

[MustangPaul]

Oz--Thanks. I don't want to sound like a total idiot when I take it in to be checked. This is beyond my skills. . . .

--P

 

[MustangPaul]

While putting around town, quite often fuel wash from the cylinder walls will make its way into the crankcase, masking oil consumption and replacing burnt oil with gas. Then when you go for extended highway trips, the heat generated in the crankcase makes the gas in the oil evaporate or burn off, making it seem like you are only using oil on freeway trips. Quite often, you are using oil at a steady rate and it is being hidden by your driving habits.

Using a quart every 2000 miles is nothing to worry about, and even new cars won't get any engine work warrantied at any consumption of a quart over 1000 miles. When I worked at GM dealers 20 years ago, the use rate had to be a quart in under 750 miles before the factory would pay for it.

At any rate, if oil isn't fouling your plugs or smoking out the tailpipe, why spend a couple grand just to save a quart here and there. Many new engines use oil at a rate faster than that anyway.

My opinion is that you would be flushing your money away. Send me the 2 grand and I will send you a quart of oil whenever you need one!

It isn't smoking or fouling. It just bothers me as it, at least seemed to be, all of a sudden. Still, I guess after 19 years, it is bound to use/leak/seep a bit of oil.

Will 2 grand get that oil overnighted to me and will I get my choice of weight and brand?

 

[Ozsum2]

Oz--Thanks. I don't want to sound like a total idiot when I take it in to be checked. This is beyond my skills. . . .

--P

No not really. Comp checks are done by removing the plugs and recording the pressure held by each cylinder. If they leak down or are greatly different than one another, you have a ring problem or valve seat problem. Vacumm checks are done with the engine running and at operating temp. The needle on the vac gauge tells you what is wrong by the way it is moving. A steady needle means all is well.

 

[Max Power]

""Will 2 grand get that oil overnighted to me and will I get my choice of weight and brand? ""

Abso-friggin-lutely!! Even synthetics! Make chack payable to:

Max Power
C/O Buy the car guy a garage fund
1234 Anystreet
USA

Thank you in advance for your investment!

 

[MustangPaul]

Max--

I appreciate the fact that you have my best interest at heart!



--P

 

[MustangPaul]

No not really. Comp checks are done by removing the plugs and recording the pressure held by each cylinder. If they leak down or are greatly different than one another, you have a ring problem or valve seat problem. Vacumm checks are done with the engine running and at operating temp. The needle on the vac gauge tells you what is wrong by the way it is moving. A steady needle means all is well.

OZ--That doesn't sound too bad. Where does one get the set up for a comp check? I'm all for buying more tools . . . .

--P

 

[Ozsum2]

OZ--That doesn't sound too bad. Where does one get the set up for a comp check? I'm all for buying more tools . . . .

--P

Just about anywhere really, from JC Whitney, to the auto parts store down the street. You can get some fair priced stuff to junk. I wouldn't go for high priced big named items. Better yet, ask if you can borrow one.

 

[MustangPaul]

Where would I test the vacuum--off the carb to the dizzy? Off of the dizzy?

 

[Ozsum2]

Where would I test the vacuum--off the carb to the dizzy? Off of the dizzy?

NO. In back of the carb, (not the PCV connection) is a hose that goes down to the modulator on the tranny. This vacumm helps the tranny shift. Unplug the hose, and slip on the vac gauge hose in it's place. This is manifold vacumm, not ported vac to the dizzy.

 

[PONY XPRESS]

If your compression & leak down tests are good you can try a heavier oil like 20w-50. This will slow down your usage.

 

[WORTH]

Max Power
C/O Buy the car guy a garage fund
1234 Anystreet
USA

LMFAO

 

[Ozsum2]

If your compression & leak down tests are good you can try a heavier oil like 20w-50. This will slow down your usage.

But remember......heavier oil has less circulation and more oil pressure. It may be an option in South Cajun Land with winter coming on.

 

[MustangPaul]

NO. In back of the carb, (not the PCV connection) is a hose that goes down to the modulator on the tranny. This vacumm helps the tranny shift. Unplug the hose, and slip on the vac gauge hose in it's place. This is manifold vacumm, not ported vac to the dizzy.

Oz and Co. Thanks! I've got the gauges and have time tomorrow to tinker with car. I'll post what I find out.

Many, many thanks. I owe all of y'all a BEvERage.

--P

 

[Ozsum2]

Oz and Co. Thanks! I've got the gauges and have time tomorrow to tinker with car. I'll post what I find out.

Many, many thanks. I owe all of y'all a BEvERage.

--P

I prefer the home brewed kind. Maybe you can hook me up with Gator McClusky. Let us know how it comes out. I think a vac gauge is one of THE most important tools on the shelf.

 

[cardude]

How does one diagnose a leaking ring or valve seal/guide short of tearing down the engine? (Or invoking your Superman-like power of X-Ray Vision?)

Thats how I find my engine problems, doesnt everyone else??