Delvac 1 used in GAS engines with "tight" clearences....?

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May 9, 2003
Fayetteville, NC
First of all, I'm now officially obsessed with this site, and I love it. ------------- I've been reading a lot about the Delvac1 5/40; It has a visc. of 15 cSt @ 100 deg C Has anyone used this a in a new engine which has tight clearances? is there any danger in putting this oil in a 4.6L Ford(97)modular engine, which is supposed to have rather tight clearences? BUT it has 87,000 miles on it, and I think the it probably doesn't have the same clearences as when it was new, right? Also: how much of cold start-benifit am I giving away if I used this oil in such an engine? Can the detergents in a "fleet-oil" like this be harmful to a modern gas engine, which demands API SL rating? (I think delvac-1 5/40 is SJ rated for gas engines...) I'd really appreciate some answers from people who have used Delvac 1 in new or relatively modern engines where a much thinner oil (5-30/10-30) was recommended by the manufacturer. Thanks a million!
There should be no problems. I put it in my son's GrandAm at under 20K miles. It is "SL" rated. In Tn you will have zero issues with starting. My son lives close to me in Southern Pa. No problems starting at -17F. Glad you are obsessed. Delvac 1 is a great oil. [Smile]
There is no harm in doing that, but your engine doesn't need that thick of a viscosity. I'd use M1 30 or 20 wt. oils in that engine. Thicker is not better in every case.
Hi,I have Delvac-1 in a 99 Ford E150 Van/4.2L six.After basically sitting (with 5K miles) [Big Grin] til Jan'04,I'll get a UOA.
We used Drydene (Castrol) 15W-40 truck oil in a company Dodge Ram 1500, 3.9 six cyl. engine, and had no problems at all. Used it from the first oil change. Company traded it with about 150,000 miles after five or so years. Don't know about how this oil will do in a colder climate, but in the Richmond, VA area it does just fine. [Cheers!]
I'm sure it will work fine at the expense of decreased fuel economy. I just ran a 5,000 mile summer run off in my '99 F150 with the 4.6l and 90,000 miles using 5w20, and it worked just fine. Just don't see a need to go thick on this series of motors. [I dont know]
My 96 T-Bird with 4.6L engine never consumed any oil until it suddenly started to use some at about 40,000 mi. Could find no leaks, so my guess is that a valve stem seal either cracked or became excessively worn. The early 4.6L engines are notorious for valve seal problems, though usually at higher miles than 40,000. So I switched from Mobil 1 5W-30 to Delvac 1. The oil consumption was reduced dramatically, but did not return to nearly zero as it was before. But I have a concern with using a 5W-40 oil, since viscosity at most of the temperatures the engine is started is higher than even a 10W-30 weight. My main goal, even more important than cutting oil consumption, is to have the least amount of wear on the valve stem seals as possible, since getting them replaced is quite expensive. Would I be better off to go back to a 5W-30 oil and put up with some oil consumption in the interest of getting oil to the seals as quickly as possible on cold starts? Or should I stay with the D1? I have considered trying GC 0W-30 to see if the oil consumption with it would be acceptable. Thanks for any input.
No, don't worry about the 5-40...nor a 5-50 for that matter. I've used all 3 grades in the same'll be fine...stick with the Delavac for reduced consumption over a 0-30, 5-10, 10-30 and even a 0-40.
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