Posted on 09/12/2010 9:59:05 AM PDT by posterchild
I do 5000 on mine, too.
I’m a salesman and about 95% of my miles are easy highway miles.
motorcycles (auto oils in motorcycles can cause catastrophic engine, clutch, and or transmission damage).
I beg to differ. I ran Pennzoil 20w50 in cooler weather and straight Pennzoil 60w in warmer weather in my “78 Shovelhead. Both were racing oils. The lower end had around 100k miles on it. I now run the same viscosity oil only now I use Valvoline racing oil, as I can’t find the Pennzoil, in my stroker Shovel. I change the oil about every 2000 miles or so and have no problems.The engine oil is separate from the tranny and my clutch is dry as I’m running an open belt primary.
There was a study published where they found a lot of the additives that were supposed to be in “motorcycle” oil simply were not there in a lot of brands.
Recently, the car developed an oil leak from a valve cover. When I removed the cover, I was shocked to see a dark brown coating of varnish covering the rockers, springs, etc.
I asked around and was told either I hadn't been changing the oil frequently enough, or I had been using inferior oil. Since I have heard some complaints about the uncertain quality of oil used by "drive-through" places, I decided to blame the oil.
Thinking I should get on a cleaning program, I asked about oil additives to use. I was advised to never clean a high mileage engine (in my case 125K miles) because the varnish may be what's preventing seals from leaking and parts from rattling.
Fortunately, I caught the problem before any of the lifters got sticky and started causing valvetrain noise. I switched to Valvoline high mileage synthetic blend and so far, so good. I did check the compression and all cylinders are within 5% of each other. Engine purrs like a kitten.
I see that you have a F350 diesel, I recently purchased a 2006 Dodge pickup with a Cummings diesel, my first diesel, I notice the oil gets very black! Does that mean I must change the oil more frequently than, say every 3000 miles? I notice you change yours at 6000 miles.
That is the problem I had with synthetics.
The car was rarely used and the seals shrank and the synth oil was happy to find an escape route.
Oil never goes bad. It just needs to be cleaned and new additives(anti corrosion, anti foaming agents, seal conditioners, etc) added.
Back in the fifties, people would drain out their oil, replace the filter, then dump their old oil back in with fresh additives. But you can’t buy additives anymore.
I never did buy into the 3,000 rule. I’ve been changing oil at 5,000 miles without fail for over 10 years on all my cars and have never had a catastrophic engine failure. I could probably push it longer but I do a lot of city driving so I want to be on safe side. Those who do mostly highway driving can easily get 7,500 between oil changes but they ought to be checking their oil more often.
Was that the infamous Renault V-6? My friend had one of them. The camshafts were totally wiped out due to lack of oil.
What year is your Suburban? The light that comes on on my 2005 GMC Envoy Denali reads "CTFOAH."
No wonder I hate union's and will never buy another GM/Chrysler product.
my uncle has a waste oil furnace in his garage...he burns the used oil from his bulldozers and from a friend’s trucking company to heat...talk about environmentally friendly...
On my Escape, which I just sold with 109,500 miles on it, I changed oil every 5000, +/- 1000 miles. The car ran great, and never had an oil burning problem throughout its life with me. I think the new owner will get another 100K out of it.
My Honda has a “percent life” indicator on the dashboard. It supposedly calculates oil life remaining based on time, total miles, and driving habits. It seems to reach the 10-15% level around 7000 miles, but I tend to change a little early, at an indicated 20% life, which works out to around 6000 miles.
My Dodge Hemi has two maintenance schedules - regular, and heavy-duty service. The regular service schedule calls for oil changes every 6000 miles, while the heavy duty calls for an oil change every 3000 miles. They’re a little vague as to what constitutes “heavy duty” service, though they mention towing as one of the criteria.
I haven’t had the Dodge very long, and the previous owner changed the oil just before I bought it. I suspect that I’ll do like I did with the Escape and go 5000 miles between changes.
The dark color is caused by heat. so is the leaky valve cover. oil oxidizes on the really hot metal parts...ie the valve train.
Click and Clack the Tappet brothers said a few years ago that todays vehicles can easily go 5000 miles between changes IF you use good oil to begin with.
In a case where the crankcase oil is shared with the tranny oil you can just change it more often before the oil molecules get too beat up. I’ve been doing that for years. Do want to avoid oil with fancy friction modifiers with a wet clutch. I’ve so far avoided buying a European four stroke with a firm requirement for Motorex $20/quart oil.
Thanks. One of the things I didn't write in the prior post is that I was told the inferior oils tend to contain higher amounts of paraffin and it's the paraffin that is a principle contributor to varnish and sludge.
As for the leaky valve cover, as I removed the bolts, no breaking force was required for the bolts near where the cover was leaking. They appear to have either worked loose on their own or, some mechanic had loosened them for some reason... hopefully not out of dishonesty.
I have some doubts about the integrity of the mechanic because at the last plug and cable change, I specified and paid for platinum plugs but as part of the valve cover gasket replacement, I changed plugs and was disappointed to find out they were resistor plugs.
Another thing I'm a little concerned about is the effect of using a synthetic blend in a heavily varnished, high mileage engine. I switched to Valvoline 5W30 high mileage synthetic blend. I guess as it begins removing sludge and varnish, I'll find out if it was the correct decision.
Never-the-less, I'm not sure how much longer I could have continued before a hydraulic lifter began sticking and valvetrain noise developed. The issue then being on my car, changing the hydraulic lifters at $10 each requires the engine first be pulled. I don't fully understand why the engine has to be pulled to change the hydraulic lifters but that's what the repair manual says.
Just call me old fashioned, but I believe the first oil change on a new vehicle/engine should be around a 1000 miles. After that you can extend it out to whatever the manufacturer recommends.
For those too young to know, those were 2 top radio programs..
In post #63 and #77, I commented on a recent discovery of dark brown varnish covering my rockers, springs, etc that I attributed to using oil of uncertain quality at whatever drive-through oil change place happened to be convenient.
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