Oil usage increase with miles on oil?

[kreigle]

I did a search on this but couldn't find anything:

My car as always burned oil as long as I have owned it, but I have recently noticed a trend in how it burns the oil.

When I first change the oil, it will go about 300 miles before I need to add any for top up - about 4-8oz. During the next 300 miles, it will will require another 12-16 oz. Currently about 1/2 way into the 3rd 300 mile period and already added another 1 qt of makeup oil (for a total of about 1 1/2 qt at about 750 miles).

I think it is strange that the oil usage is not uniform, that it starts of not using any oil when it is fresh, and then requiring increasing amounts of top-up oil as the mileage accumulates.

I am in my 2nd AutoRx clean cycle on this car, and I am beginning to feel that is is a futile excercise as I can't keep oil in it long enough to do anything. The oil usage rate has been relatively unchanged for about the last 2 years, and I've tried what seems like everything short of rebuilding the engine to clear it up.

 

[Jelly]

quote:

---

Originally posted by kreigle:
(for a total of about 1 1/2 qt at about 750 miles)

---

Have you figured out why it's using this much oil?

 

[Gary Allan]

That's some fairly serious usage there. Not the end of the world ..but it can't make you feel good either.

My Caravan 3.0 mitsu would use no oil ..then use it routinely after 3000 miles ..synth or dino. This I attributed to some oil fatigue factor. In your case the stuff isn't anywhere near "used". This stuff still has to be clean on the dipstick.

What engine is this ..mileage..condition..and what oil are you using??? I'll assume that you don't have any obvious leaks ...since if you did you'ld have already answered your own question.

 

[John K]

I have noticed this and asked a similar question.. don't think I got any replies. What I've experienced is that in 3000 miles it might be down a quart, and if I don't do an oil change I'll add a quart and then be down another qt in say, 1500 miles. I wondered if that was an indication of oxidation, or what?

 

[rshaw125]

I think it is because the oil shears -it gets a bit thinner as the miles accumulate. The viscosity gets higher?
My Voyager van 3.0 always does this. I have been using Supertech in it for a couple of years. The first 1500 miles it stays full. Then it starts to burn it. I have to add a quart to get it to aprox. 4,000 miles when I change it.

 

[JMG]

I have a similar problem. However mine doesnt go through oil like yours. My Accord will not burn/lose oil until the oil has about 5-6K miles on it. Then I may lose 1/4 qt. Not bad...

Oil always comes out brown tho, not black. So I dont know...

 

[Ugly3]

My Chrysler 3800 V6 uses 1/2 quart in 5,000 miles, I add to full at that point and run to 10,000 miles. In the second 5,000 miles it generally uses a little less than 1/2 quart.

Seems odd to me.

 

[Gary Allan]

Some engines just appear hard on oil. Many don't.

For those who see accellerated consumption as the mileage increases ...either need to switch weights or shorten the OCI (sometimes switching weights isn't possible and sometimes it doesn't work to reduce the consumption). On mine it didn't seem to matter. My 3.0 was a true 3k/3m OCI or it consumed it.


..but kreigle's problem is WAY beyond that. We need more info....

 

[kreigle]

quote:

---

Originally posted by Gary Allan:
In your case the stuff isn't anywhere near "used". This stuff still has to be clean on the dipstick.

What engine is this ..mileage..condition..and what oil are you using??? I'll assume that you don't have any obvious leaks ...since if you did you'ld have already answered your own question.

---

Actually, it is already turning black. It turns the oil black in
This is a 1991 Honda Prelude with a 2.1 has 177k miles. purchased in 1996 with 108k, used some oil then, probably 1 qt every 2k. Oil usage has increased mostlly within the last several years.

re leaks: in the last 45000mi I have replaced:
oil pan gasket
front oil seal
front cam seals
rear cam o-rings
valve cover gasket

no drips or wet spots under or on the engine
no blue smoke, unless I let it idle for more the 10 minutes

First AutoRx cycle was with Rotella 15w-40 clean and Delvac 1300 15w-40 rinse. Last OCI was SuperTech 5w-30. Currently using Pennz 10w-30. Same oil consumption with all weights.

[ February 08, 2005, 11:43 AM: Message edited by: kreigle ]

 

[Gary Allan]

How does a tune up hold up on it? Any deposits on the plugs? How's the intake/throttle body look for oil residue? Have you serviced the PCV system? This may be what causes your oil to turn black so quickly.

In the absense of leaks and obvious oil plumage, I'd say that it must be entering the intake stream at just the right rate to be handled by the combustion process without apparent evidence (the blue cloud). The long idle smoking can by a combination of head temp and valve oil seals and oil just sitting in the exhaust waiting for a decent push from you driving away to push it out ..but this would be a first for me as the primary cause for this level of consumption.

I saw a reference to "first Auto-Rx". Does this mean you're doing the over 100k double dose prescription??

edit: What's your typical usage of this vehicle?

[ February 08, 2005, 01:21 PM: Message edited by: Gary Allan ]

 

[kreigle]

quote:

---

Originally posted by Gary Allan:
How does a tune up hold up on it? Any deposits on the plugs? How's the intake/throttle body look for oil residue? Have you serviced the PCV system? This may be what causes your oil to turn black so quickly.

---

I installed an aftermarket header last Jan (04) because the original downpipe broke. from then until after the first AutoRx treatment (July 05) the plugs were dry black with white streaks on the insulators. Before that they were white, and right now they are white. Plugs were replaced in Aug because I thought they were not working properly, but the new plugs did the same thing. I ran 7 tanks with FP before they cleaned up.

The TB/Intake was cleaned/SeaFoamed in August 05. TB butterfly had black residue on the back. The intake runners were paper-towelled out back in 2003 when I replace the cooling system hoses and had to take the top half on the intake off. They were full of black oily residue and pooled gasoline.

I am currently on the 3rd PCV valve since I bought the car, it is a 3-4 year old Factory Honda valve and was cleaned in Aug and again 2 months ago when I did the front oil seal and timing belt. None of the aftermarket PCV valves I have bought would fit properly.

quote:

---

Originally posted by Gary Allan:
In the absense of leaks and obvious oil plumage, I'd say that it must be entering the intake stream at just the right rate to be handled by the combustion process without apparent evidence (the blue cloud). The long idle smoking can by a combination of head temp and valve oil seals and oil just sitting in the exhaust waiting for a decent push from you driving away to push it out ..but this would be a first for me as the primary cause for this level of consumption.

---

I was thinking valve guide seals, but just how much oil gan get past these? I takes all day just to replace the timing belt, I cant afford the downtime to pull the head.

quote:

---

Originally posted by Gary Allan:
I saw a reference to "first Auto-Rx". Does this mean you're doing the over 100k double dose prescription??

---

Yes. I am halfway through the second clean cycle right now. I don't write down how much I use to top up normally, but I think the first clean cycle took 2-3 qt.

quote:

---

Originally posted by Gary Allan:
edit: What's your typical usage of this vehicle?

---

Daily Driver: 6-7 mi each way to work 90% city
Mondays I go to my parents' (3 mi from work, 8 mi from there to my house)over my lunch break to pick up my son and take him home.
Tues-Thur I go to to my parents right after work to pick up my son as my wife is in class.
Fri I drive to my parents to drop off the car as I can't park on the street in the city over the weekend.

I probably put 500-600 miles per month on the car.

 

[Gary Allan]

Everything you report about the intake looks about average/normal/typical. I would be more concerned if your throttle body were oil soaked above the throttle plate.

I'm unsure if you have to remove the head to service the valve seals on this engine ..but you would have to disturb the cam and timing belt (probably).

I would wait until you're through the second Auto-Rx treatment (which in your case is a long time) before attempting to lock this cause down. You have a very limited use duration on this engine. It virtually never warms up at all.

Given your limited useage ..and the high cost of maintenance that you've already put into it, if it's not causing other operational troubles (fouled plugs, etc.) ..I would live with this condition. It's neither high in cost (compared to the static fixed cost of owning, insuring, maintaining a car) nor is it so high in frequency (due to your mileage) to require undo attention. It sound like a quart every couple of weeks.

 

[kreigle]

quote:

---

Originally posted by Gary Allan:
I'm unsure if you have to remove the head to service the valve seals on this engine ..but you would have to disturb the cam and timing belt (probably).

---

That is something I was going to try to look into when the weather warmed back up. It is an interference engine, and I can take the valve keepers out with the head in place (this actually happened by accident one time while adjusting the valve lash). I just don't know if I can get the retainers and springs out past the camshaft.

quote:

---

Originally posted by Gary Allan:
I would wait until you're through the second Auto-Rx treatment (which in your case is a long time) before attempting to lock this cause down. You have a very limited use duration on this engine. It virtually never warms up at all.

---

Well I hope it does help. When the engine does truly warm up, the oil usage gets worse. If I've been driving for more that 40 minutes, then I get blue everytime I stop at traffic lights. Oil burning is very common on this engine, and I have to wonder if it isn't a design flaw. Honda used a different cylinder sleeve material than in the B20 version of the Prelude, but the rest of the engine internals are the same.
I do a lot of reading over at www.preludepower.com, and if you do a search there in the "3rd Gen" forum for "b21 oil burning", it seems that the consensus over there is that the rings go bad quickly. Since I still have very good compression #s, I don't belive that the rings are bad; however, this particular engine does seem to be extremely hard on the oil and may coke oil rings/return holes up.

If I am correct, then I would have run a good synthetic to get this under control, but it would be expensive at this point, unless I could find one that is good at dispersing existing coke deposits.

quote:

---

Originally posted by Gary Allan:
It's neither high in cost (compared to the static fixed cost of owning, insuring, maintaining a car) nor is it so high in frequency (due to your mileage) to require undo attention. It sound like a quart every couple of weeks.

---

Yeah... I've got lots of cheap oil (4+ cases of $1 or less/qt Shell/Exxon/Valvoline) plus some Valv. blend and MaxLife. If I don't use the car for highway trips, that works out to 2qts/month. Highway driving results in higher oil usage, unless the oil was just changed. I figure if I can time oil changes just before possible highway trips then I can reduce the need to top up on the road.

I just wish I could get control of this before it gets out of hand. Oil consumption has doubled in just the last 2 yrs. Some B21s on preludepower.com were up to 1qt/<150mi before they were swapped out.

 

[kreigle]

quote:

---

Originally posted by Gary Allan:
This can be anything from long term scale on the head's internal casting to eroded water pump vanes.

The fact that your plugs survive fairly long term suggests that the leakage is limited to the exhaust valve guides.

---

OK. Now I'm getting off-topic from my original question, which was why does my car burn oil faster the longer it is in the engine...

Anyway...

The waterpump was replaced in 2003 (Honda OEM btw), when I replaced most of the cooling hoses and the 13yr old radiator cap. I filled up at that time with Prestone 'DexCool equivalent', since it was the only non-silicate antifreeze I could find at the time. In April the following year, I noticed that the coolant had turned cloudy brown

and dumped it out. Ran 3 back-to-back Prestone Flush treatments (3-4 days each), flushed out with distilled water, installed G-05 and noticed a week later that the radiator kept getting air space in it.

turned out the radiator cap was leaking air when the engine cooled down .. replaced radiator cap with Honda OEM and has been fine since.

I suppose there could still be deposits in the head, or excessive corrosion of the water pump vanes from the Prestone. I still get rust chunks from the radiator drain whenever I check the coolant for cloudiness, so who knows

The exhaust valves are towards the front of the car and are the easiest to reach, so I will probably try to switch those seals out first.

BTW I still have an ounce or two of AutoRx left in the bottle - maybe I should go ahead and add it to the next top-off to make up for whats been burned off?

 

[Gary Allan]

Man ...I have got to say that you've left no stone unturned here

Everything that I've thrown out there ...you've sorta already 'been there - done that'.

At this point I would say that you've done enough repair/maintenance to reasonably remedy just about ...anything (and I do mean just about anything).

All that's left for "just short of throwing in the towel" on this is the valve seals.

[ February 09, 2005, 04:49 PM: Message edited by: Gary Allan ]

 

[Gary Allan]

quote:

---

When the engine does truly warm up, the oil usage gets worse. If I've been driving for more that 40 minutes, then I get blue everytime I stop at traffic lights.

---

This points to valve guide seals in my experience. As the oil thins it just flow too easily. Head temp may be a factor in this. The reason that I feel head temp plays a role in it is that the smoking is tremendous when at idle ..enough, or one could reason, that it would show when driving at a slow speed ...or just sitting there with the idle raised ..yet you may not see anything if you raise the idle while sitting still. This can be anything from long term scale on the head's internal casting to eroded water pump vanes.

Before I auto-rx'd my Caravan ..I had the same situation. No visble smoke while driving ..lots of smoke when idled. Enough smoke when idled (a true fogger) that it would have surely shown itself when driving if the leakage was still present while in motion. Since the oil flow MUST be higher off idle ..one can reasonably conclude that there is a thermal component to the leakage where oil flow and coolant flow are reduced.

The fact that your plugs survive fairly long term suggests that the leakage is limited to the exhaust valve guides.

 

[kreigle]

1179mi and just put in the last half of the 2nd top-off qt (still not quite back up to full line, but not at add anymore, either).

The oil is black - looks like soy sauce on the dipstick and oil cap threads. Right on time; it seems to always look like this by 1k.

Any benefit to scraping up the cash for a UOA? Would it tell me anything useful?

 

[Brikhead]

I use 10w30 dino in my `93 Volvo 240 (197k miles) and it has a very predictable consumption pattern. After 1500 mi. on new oil, it will start to drink about 3oz every 500 mi until the next OCI(@3k). Its like clockwork.....the car won't eat a drop while the oil is "fresh". But after 1.5k, I can watch the level on the dipstick drop(in mm increments).

 

[Gary Allan]

quote:

---

Any benefit to scraping up the cash for a UOA? Would it tell me anything useful?

---

I'd like to see it. You've got to have something odd going on to beat up some of the oils that you've gone through.

I predict excessive fuel dilution (we could form a pool here).

 

[kreigle]

quote:

---

Originally posted by Gary Allan:

quote:

---

Any benefit to scraping up the cash for a UOA? Would it tell me anything useful?

---

I'd like to see it. You've got to have something odd going on to beat up some of the oils that you've gone through.

I predict excessive fuel dilution (we could form a pool here).

---

I am just past 1500mi on this clean cycle. Does anyone see any point to pushing this out to 2000? I have added 2.75 qt top-up oil to date (4qt sump).

I have an oil sample kit from Blackstone. I asked for the Dyson analysis when I ordered the kit. Am I wasting my money on the extra analysis on such a short interval or is it a good idea to get as much information from this oil as possible?

I won't be able to drop the oil until the weekend as it is too dark when I get off work to crawl under the car.