Diesel rated oil in gas engine, Why Not?

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I just watched Two Guys Garage TV show and they made a point of saying you would NOT want to run an oil that is rated for a diesel engine in your gas engine. Then they showed the labels on the different oil cans to tell the difference . My question is why not? I've always thought that diesel's required a higher grade oil and putting it in a gas engine would be just great. How am I wrong? [I dont know] Denny...
 
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This topic has been covered ad nauseum here. Basically, if the oil contains both a rating for petrol engines (ie: API SL, API SM, etc.), and for diesel engines (ie: API CF, API CI-4, etc.), it is perfectly safe to use in a petrol engine. Some petrol-fired cars contain gas-path instruments such as oxygen sensors that are sensitive to an additive, ZDDP, used in diesel engine-rated oils as an anti-wear additive. This really isn't too much of a problem unless you do overly frequent oil changes.
 
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I also saw 2 guys garage allow a caliper to hang by the brake hose while they changed rotors. Real bunch of geniuses on TV.
 
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Nah, it's an old story, about diesle oils having too much ash for petrol engines. There are many, many diesel rated oils that are ONLY diesel rated, and shouldn't be used in petrol engines. Fleet oils are rated both ways, and are therefore acceptable.
 
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Both Delo 400/Synth and Delvac Super as well as Delvac-I are all multi fuel rated and I have been using them actively in both petrol and diesel vehicles without any ill effects.
 
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I used Delo 400 last summer...No consumption, and performed flawlessly.
 
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Ditto Gurka. 1 gallon jugs are still good deals on Delo & Del Vac,Rotella at SprawlMart but the price went up here(Central Texas) yesterday. I bought 3 gallons of T&SUV last nite before the increase hits the synthetics. [HAIL 2 U!]
 
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In some cases, even oil rated CI-4/SL can cause long term damage in modern 3-way catalytic converters...what year, post '94? The high SAPS, sulfated ash, phosphorus, and sulfur are the culprits.
 
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Is Mobil 1 5w40 truck and SUV oil an issue with 3-way cats? been using it in my 1995 BMW 525i for about 9,000 miles with no apparent issues. TIA
 
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Yes, but would this additive package only be a problem if the vehicle in question consumed oil (meaning more than 1 quart per OC). ZDDP is only a problem if the lubricant is getting burned along with the fuel.
 
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I run all my collector cars on diesel oil: either Delo or Rotella. One car had nothing but diesel oil for 45,000 hard street miles over 10 years. When I pulled the engine to regasket it, I was shocked at how clean the inside was. It looked like it just came out of the machine shop. I also diesel oil in all my lawn and garden equipment too. I am sold on it.
 
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No! You are not wrong. However there are two caveates. 1 Does the diesel oil meet your CAR's specifications, i.e. SM SL. if it does then YAHOO 2 to a lesser extent viscosity. So for example, I just happened to run Mobil One 5w30,0w20,5w20,5w40. Do I wish I can go back to one grade (say 5w30/0w40?) U betcha. There are two applications that can run 5w30 without additional specifications. The next application just happens to require 5w30, BUT has the GM 4178 M specification. The 0w20, 5w20 meets Ford/Honda specifications. The 5w40 can be run in two of the first applications and I would have no concerns back filling the third but again 5w40 does not meet the GM 4178 M specification. 5w40 in the diesel application has no problems running 25,000 OCI's!!! Now that is pretty awesome.
 
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I used Mobil Delvac in a 89 Mazda P/U gasoilne engine back around 1993. Too much ash may have killed my EGR valve. Don't know for sure,but would not chance it again. Was used for about two years.
 
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quote:
I also saw 2 guys garage allow a caliper to hang by the brake hose while they changed rotors. Real bunch of geniuses on TV.
I guess you've never changed the brakes on your vehicle
 
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quote:
I guess you've never changed the brakes on your vehicle
I've changed the brakes on many vehicles. I'm a mechanic. Do you let the caliper hang by the brake hose?
 
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[LOL!] [Off Topic!] [No no] Gotta love those HDEOs. Still the best bang for the buck for OTC oil. If they are good enough for a John Deere....they will make a GMC product [Happy]
 
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I had a problem with Rotella 10w30 in one of my VWs a couple years ago. After the oil change I drove about 10 miles on the interstate. When I exited, smoke was rolling out from under the hood and oil was leaking out everywhere. I opened the hood and oil had blown out all over the engine. It was smoking off the exhaust manifold…a total mess, and I was 2 quarts low. Then I saw the oil cap on a strut tower, NOT on the valve cover!!! [Bang Head] Ok, Rotella was not the problem; it was a loose nut behind the wheel. [Big Grin] Any current S rated oil (SL, SM….) is fine to use in a gas engine, requiring such a fluid. If the oil wasn’t suitable, it WOULDN’T have the S rating! This car usually has M1 15w50, but a crank leak has me using conventional oils right now. For the past 2 or 3 years I have been running Delo or Rotella 15w40. Since the ‘Mart’ has started carrying Rotella 10w30, I run that in the winter. Several years, now and the engine has not blown-up yet.
 
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