What does this oil use pattern indicate?

Messages
2,187
Location
Arizona
If a gasoline engine doesn't use oil when driving around town and county roads (under 60 mph), but uses some when driving at higher speeds (75 and over), what does that indicate about the engine? When I say "some," I mean a pint to a quart (depending upon brand used) in 2000 miles. Any specific kind of wear or something that could be addressed easily and corrected? Thanks for any help.
 
Messages
34,198
Location
South Jersey
It's very normal and very common for small 4 cylinder engines to burn oil of any brand at high speeds. My old Toyota Corolla @ 80 mph was turning 3,000 rpms. It would drink about 1 qt every 2-3k miles. Slower speeds, the lower the rpm. To help reduce consumption in this case, I'd use an oil with low volatility and or switch to a thicker viscosity. [Smile]
 
Messages
34,198
Location
South Jersey
"If so, if you do stops from a high speed and do engine braking, the strong vacuum created in these conditions will pull oil past the rings to be burned" Do you mean by down shifting or just using the brakes and putting it in neutral? I use my brakes and put the car in neutral.
 
Messages
556
Location
Melbourne Australia
quote:
Originally posted by buster: Do you mean by down shifting or just using the brakes and putting it in neutral?
I think he means just using engine braking to slow down (eg, shifting into 2nd and 45mph)
quote:
I use my brakes and put the car in neutral.
Your clutch will last a long time [Wink]
 
Messages
1,294
Location
Western Washington
quote:
Originally posted by buster: I use my brakes and put the car in neutral.
If you just stay in gear as you slow down instead of going into neutral, you get much better gas mileage, plus your engine isn't idling: it's getting better lubrication.
 
Messages
39,805
Location
Pottstown, PA
I'd look to your PCV system ..blowby ..that type of issue. It's obviously not severe ..and a tweek in visc may end it. It don't think your reaching the cylinder pressure in your other driving modes.
 
Messages
34,198
Location
South Jersey
quote:
If you just stay in gear as you slow down instead of going into neutral, you get much better gas mileage, plus your engine isn't idling: it's getting better lubrication.
Really? So down shifting is preferable? I always thought putting it in neutral and using the brakes is easier on the car, especially the trans. I downshift often as well but if I'm in 5th gear and am comming to a light, I'll throw it in neutral and brake. Keeping in 5th the whole down would be "lugging" the engine. Many times I'll down shift through each go as well.
 
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13,132
Location
By Detroit
[Off Topic!] I guess it depend on whether the computer controlled EFI vehicles cut the fuel flow to low levels for engine braking situations. Basically I don't worry about clutch wear and downshift when I please for the fun of it. [Big Grin] I have even gotten to where I will pull my wife's Aerostar automatic out of OD on the freeway exit ramp. This actually has two purposes: 1) the extra engine braking and 2) I want it out of OD for surface streets so the engine will rev a bit higher to help keep the cobwebs from forming. Tooling down a 45 mph surface street at 1800 rpm with an engine that has a power band of (torque peak to hp peak, about 3600 to 4800 rpm) seems absurd. Out of OD it can run in the mid 2000s at least.
 
Messages
10,905
Location
Nokesville, VA
quote:
Originally posted by TallPaul: I guess it depend on whether the computer controlled EFI vehicles cut the fuel flow to low levels for engine braking situations.
They do. They shut the injectors off till the engine speed drops close to idle. One of the advantages of EFI emissions-wise is that emissions during deceleration are greatly reduced compared to carburetion.
 
Messages
5,785
Location
Dixie
What type of engine is it? How many miles are on it? How heavy an oil are you using and is it a conventional oil or a synthetic? If it's the latter, is it a Group III base stock or a PAO/Ester basestock? Hard to diagnose the "patient" without follow up questions. [Smile] These type of oil consumption can be easily addressed, but there are typically tradeoffs like reduced fuel efficiency and/or cold weather performance.... Tooslick
 

bulwnkl

Thread starter
Messages
2,187
Location
Arizona
It's a 2-liter, SOHC 4 cylinder with HLAs. We bought it early last year with just under 36,000 miles on it, and it now has ~53,000. When we got it, I immediately performed all the maintenance specified for the 30,000 miles service: Air filter, spark plugs, check a milion things, be on your way. I also switched it to RedLine 10W30 and a PureOne filter and replaced both the PCV valve and the piece of filtering foam in the airbox end of the PCV system. That RedLine was run a short interval (~2,000 miles) and was followed by Amsoil 10W30 and an Amsoil filter for ~7,700 miles. That was followed by M1 10W30 and a PureOne for ~5,000 miles, with some Schaeffer Neutra added at 1 oz/qt at the end of the OCI. Then, an Amsoil Dual-Remote system was added (still using a PureOne full-flow) and Exxon SuperFlo 10W30 (SM/GF-4) was run for ~2,000 miles. Switched back to RedLine 10W30 at that point. So, as you see, I have never knowingly run any Group III oils, though I read here that the Exxon I put in may have been partly G-III. The car runs beautifully and I have no specific complaint. Mileage runs 32-35 around town and county roads, very slightly lower at high speed. We've also gotten a few hundredths short of 40 mpg on an extended highway (not freeway) trip. I can't recall how much the A/C lowered mileage last year. {EDIT: I forgot to mention that I don't have a tachometer so I don't know what the RPM is at 75 mph. I had an earlier Neon years ago and it wasn't turning too fast, but these have a lower final drive ratio.} I have avoided (until now) saying it's a Neon because I was hoping to keep prejudices about the brand or model out of this. Coincidentally, this is the same consumption pattern I used to get out of my 240Z. I'll check the PCV suggestion. Some folks report these engines to dump huge amounts of oil out the PCV hose when driven hard, although we don't ever drive it that way. I thought the reports had to do with cornering/street racing, but I'm not positive. [ May 29, 2005, 03:25 PM: Message edited by: bulwnkl ]
 
Messages
1,294
Location
Western Washington
quote:
Originally posted by buster: Really? So down shifting is preferable? I always thought putting it in neutral and using the brakes is easier on the car, especially the trans. I downshift often as well but if I'm in 5th gear and am comming to a light, I'll throw it in neutral and brake. Keeping in 5th the whole down would be "lugging" the engine. Many times I'll down shift through each go as well.
I don't mean downshifting even. I usually just stay in whatever gear I was in before until I get down to 1300-1500 rpm, or until I need to get on the gas. If I'm getting off of the freeway, I just stay in fifth until I need throttle or my rpms drop too low. When I need to get on the gas, I just downshift at the lower speed like I'd have to anyway. By the time my engine speed drops below my rpm limit, I'm usually slowing to a stop anyway, and just go into neutral then. FWIW, my dad's old Cadillac had an instant MPG gauge. When the tranny was locked up and you let it coast while in gear, that thing would show 60 mpg. It had a big V8 too!
 
Messages
23,591
quote:
Do you mean by down shifting or just using the brakes and putting it in neutral? I use my brakes and put the car in neutral.
That's in most states and most countries illegal for a very obvious reason. [Wink] What I find funny is that people always talk about my high oil consumption (ca 0.5 qt/1k miles), yet at the same time they say that kind of or even higher consumption is normal at high RPM. I don't know about you all, but for me high RPM is 5k and up. I spend an a very large amount of time driving at 3000-4500 RPM. Too me that's the middle RPM range! My intake manifold switches to a shorter runner at only 4100 RPM. I consider anything under 3k RPM cruising. Whoops, I almost said coasting. [Razz]
 
Messages
738
Location
Suburban St. Louis
quote:
in some states it is illegal to coast in neutral, even when braking
I'm sure that soon the black box will upload the coasting information to a satellite link and you'll get a ticket in the mail.
 
Messages
10,905
Location
Nokesville, VA
quote:
Originally posted by dkcase: I'm sure that soon the black box will upload the coasting information to a satellite link and you'll get a ticket in the mail.
I'm not sure how they enforce it BUT it makes sense if you consider that the engine could stall while you are in neutral with the attendant loss of (1) power steering assist and (2) vacuum brake boost.
 
Messages
10,905
Location
Nokesville, VA
quote:
Originally posted by Palut: FWIW, my dad's old Cadillac had an instant MPG gauge. When the tranny was locked up and you let it coast while in gear, that thing would show 60 mpg. It had a big V8 too!
I have that in my 1988 Ford Mustang 5.0. (It's a trip computer from a 1983 Ford Thunderbird which I wired in for full functionality). It's shown as high as 150MPG when coasting in 5th gear.
 
Messages
12,385
Location
Northern CA
quote:
Originally posted by brianl703:
quote:
Originally posted by dkcase: I'm sure that soon the black box will upload the coasting information to a satellite link and you'll get a ticket in the mail.
I'm not sure how they enforce it BUT it makes sense if you consider that the engine could stall while you are in neutral with the attendant loss of (1) power steering assist and (2) vacuum brake boost.

The laws have been around since long before power steering and brakes. They were originally written because brakes used to be so bad.
 
Messages
10,905
Location
Nokesville, VA
quote:
Originally posted by XS650: The laws have been around since long before power steering and brakes. They were originally written because brakes used to be so bad.
That I don't doubt. I used to have a crappy car whose engine would sometimes stall if steered while moving and the clutch pushed in. That, I assumed, is reason enough that these laws exist (or still exist).
 
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