:greendude Anyone, including Bbob! Are you positively sure Rotella T 15w40 is good for the 4.9. I heard from a Mechanic that Diesel oil doesn't mix well with regular gasoline, AND diesel oil doesnt flow as high in the engine and, I will begin to hear the lifters "ticking" in the future. I am hesitant to put this oill in my car because it has been working excellent as it is!:suspect:

If it ain't broke don't fix it. Why would you put an oil developed for diesel engines in a gas engine? If it's running fine and your happy what are you looking to change?

:Poke: well Bbob was saying that this diesel oil works really good for the 4.9 and it has extra ZDP antiwear agents in it. Im lookin basically to extend the life of my car as much as possible.

i use it for my 92 sdv. seems to help with the main bearing knock. Haven't noticed any other diff. than that.

bob will tell you the diesel oil "not mixing well" is a old wives tale....

I have used nothing but mobil 1 delvac 15w40 (a compeditor to shell rotella) in my 94 4.9 for the past 24,000 miles , no problem ...

Before that when i was in the airforce our whole fleet used mobil 1 delvac this incuded a range of gas engines from the Dodge 360, Chevy/Buick 3.8, Chevy 350 ,4.3, Ford 302,351,460,300 in additiont ot he heavy duty truck engines like Detriot 8v92tta's..we did this for years with no problem

the 4.X pushrod series engines love this oil , typical "gas engine oils" have speical additves to make the oil more slippry and runny to promote good gas milage , whereas these "diesel" oils are speically desgined for the high imapct and rough life of a diesel engines , Shell Rotella and Mobil One delvac boath meet and exceed SAE requiremnts for gas engines , along with diesels ....Now the Diesel oils of 20-30 years ago was a diffrent story , but the modern day "diesel engine oil" is a amazing oil that is beatter than the factory fill for the 4100,4.5 and 4.9 litre cadillac engine ....

ill see if i can grub up some quotes from Bbob on this for you .....

id also like to note this delvac and rotella is particulay good for the valve train, mains and oil pump...

and do youself a favor and fisnish off that oil change with a "AC Delco Duraguard" Filter from your local dealer ..

and here is a quote from bob

I always recommend that anyone running an engine from the mid-80's and earlier use one of the non-GF-3 or non-GF-4 rated oils on the market. Those Heavy Duty oils are NOT friction modified and have higher levels of antiwear additives. Oils such as DelVac, Delo and Rotella , which are typically available in gallon jugs at Walmart and are viewed as "18 wheeler diesel oils" are EXCELLENT for earllier model engines. Modern engines of the 90's and 2000 and later are designed to run on the GF-3/4 friction modified oils with lower levels of antiwear treatment. The Delo/Delvac/Rotella oils meet the SL performance requirements but cannot be GF-3/4 rated due to the lack of friction modifiers for fuel economy. This is a good thing in an engine that is more sensitive to lubrication requirements.
..
http://www.cadillacforums.com/forums/showthread.php?t=10683

also this thread is best for info on this subject:
http://www.cadillacforums.com/forums/showthread.php?p=137604#post137604

sorry guys im raiding my best of bbob thread where we stuck some great info from bob :
http://www.cadillacforums.com/forums/showthread.php?p=137605#post137605

ok ill quit now ....

i gotta change my oil now ....funny this subject came up today

Here's my take. I use, and always have, only Valvoline 10W30 and WIX filters. The day before I change the oil I add a pint of Marvel Mystery Oil. Then with the new oil I add a quart of Lucas Oil treatment. I used to use STP Oil treatment but I switched to Lucas because of the hype. My 4.5 has 215k on in and has never had engine work of any kind done, runs like a top, no noise, it just runs.

This is the same ritual I've used on every car I've owned. My 78' Coupe Deville had almost 400k on it when the radiator developed an undetected leak, overheated and blew a head gasket.

If theres a tick or a small noise you're concerned about, add some STP oil treatment. If it doesn't go away it may be time for repairs.


:Poke: well Bbob was saying that this diesel oil works really good for the 4.9 and it has extra ZDP antiwear agents in it. Im lookin basically to extend the life of my car as much as possible.

Before adding STP-anything to your engine, you might be wiser just to add a heavier weight oil to the crankcase to reduce any ticking noise. I'm using 15w40 diesel oil in my HT4100 with baldwin/amsoil oil filter, and it's running better than it ever has.

Using the heavier 15w40 diesel oil instead of 10w30 will generally quiet any ticking noise from the lifters and elsewhere, and also provide superior lubrication for the engine. Aftermarket supplements are never recommended and almost always do more harm than good. Lucas treatments can potentially foam up in the engine, and STP... well, is kind of like using a FRAM oil filter.. :p

Interesting. I have used STP for years and everyone makes fun of it but have you ever gotten that crap on your hands and tried to hold onto something. Pretty slick stuff. And Lucas, how can you bash that, I thought that was the product everyone used. And the Marvel Mystery oil the day before acts as a cleaner to bring any build up into the pan / filter just before draining.

Now I do agree with the heavier weight oil. I used to go for the 20W 50 in the older 425 and my racing 327 / 350 but it just doesn't feel right in a newer 4.5. Plus like I said, 215k no problems. If it ain't broke don't fix it.

Like I said this is my ritual and it seems to work for me.

thats what it all boils down to code , its what makes you feel good ....anything outside the ht4100 enjoys anything extra besides the typical factory recomded diet , the ht4100s oil pump and distributor gear really need the benfits of the devlac rotella.

but ive never belived in the snake oils , there is only 2 "additives" i belive in , marvel mystery oil ,and GM EOS which is far more superior to STP oil treatment ...

Marvel mysery oil (lol bad joke) was quite useful when i worked int he fire dept , we had gallons of the stuff , it was rally great for reviveing old air brake componets and adding to diesel fuel among other apps we had for it ...the guy that turned me onto the stuff was about 8,000 years old and swore by it .....

I run Mobil 1 synthetic 10W-30 w/ AC Delco filters. Have been since I bought the car with 79,917 miles. less then 2 years later, she now has 103,118 and runs amazing. When I got the car, it had an AC Delco filter, not sure what type of oil. I change the oil according to the oil life monitor.

I am sticking with Mobil 1, this oil change I used the "extended performance" one, it was only a dollar/qt. more, so it wasn't a big deal. the engine is squeeky clean inside and runs great. I am interested to see what it'll look like in the future with lots of miles on it if it ever has to be torn down....

I do have an oil leak though, from what I can see it looks to be the engine oil cooler lines, or the coupler at the oil pump.... havn't spent much time with it, although in the last few months it has seem to gotten worse, and I don't like it.... I don't believe it is from the oil I use though, so I will keep doing what I am doing.

I run Mobil 1 synthetic 10W-30 w/ AC Delco filters. Have been since I bought the car with 79,917 miles. less then 2 years later, she now has 103,118 and runs amazing. When I got the car, it had an AC Delco filter, not sure what type of oil. I change the oil according to the oil life monitor.

I am sticking with Mobil 1, this oil change I used the "extended performance" one, it was only a dollar/qt. more, so it wasn't a big deal. the engine is squeeky clean inside and runs great. I am interested to see what it'll look like in the future with lots of miles on it if it ever has to be torn down....

I do have an oil leak though, from what I can see it looks to be the engine oil cooler lines, or the coupler at the oil pump.... havn't spent much time with it, although in the last few months it has seem to gotten worse, and I don't like it.... I don't believe it is from the oil I use though, so I will keep doing what I am doing.
be careful if you screw witht he fitting at the oil filter adapter ...its wicked easy to crack the dapter where the fitting threads in ...prolly best bet is to get new o rings for the fittings and where the adapter connects to the engine also teflon tape the threads ont he adapter ...just dont over tighten ...i made that 88 dollar mistake

Yes....I am sure that the 15W40 Delo/Delvac/Rotella is an excellent oil for the 4.9. Lots of old wives tales out there about oil...most of them have their roots in oils from decades ago....the current HD diesel oils are excellent products and work well in gasoline engines. Read the bottle....it is rated SL along with all the diesel performance ratings. SL is a gasoline engine rating so that means that the oil has been tested and validated on the gasoline engine tests for the SL rating...so it will not be the first time that the oil was used in a gasoline engine. Older "diesel" oils (20 or 30 years older) were strictly rated for the diesel specs and did not meet the gasoline engine specs. That was ages and many oil development steps ago.

If the oil cooler lines at the adapter are leaking do NOT be tempted to simply overtighten them or put teflon tape on them. The lines should seal fine with just finger torque on the line nuts. The actually sealing mechanism is an o-ring on the end of the tubing fitting. Likely that o-ring is getting tired and needs to be replaced. Simple and easy to do. Overtightening the line nut doesn't increase the sealing of the o-ring. Since the line nuts do not seal around the threads putting teflon tape on them is inadvisable. It will do nothting to aid in sealing and it will reduce friction in the joint considerably causing you to effectively overtorque the nuts and possibly crack the oil filter adapter. Even if you seal up the threads of the nut the leaking oil would simply leak between the tube and the nut itself, not around the threads. So...sealing up the threads is pointless.

yeah, like i said, I need to clean it all up and check it out again.

It is at the point now, where if the car sits for about 5 hours, there are a couple drips under it :(

From what I could see, the oil seems to be on the underside of the oil cooler lines, it follows it down. It also pools up on the left side of the engine (right when looking at it from the front) kinda infront of the airbox, but where the edge of the valve cover is, it pools up there, then drips on the exhaust manifold/exhaust pipe and burns off... you cvan see the smoke sometimes and even smell the oil burning off. When I did an oil change last week, I was surprised to see the whole underbody of the front of the car.... engine cradle, cross members, oil pan, transmission oil pan etc.... all covered with oil, it was not like this, let alone this bad on the last oil change (before it was put away for the winter)

Oil consumption has also gone up, because it is leaking. I put 6 quarts in with the oil change and new filter, and it put it a little above add on the dipstick... I find that strange as the engine is supposed to only take 5.5qts. So I have an extra quart I keep with the car and add as needed....

The more I think about it, it really isn't good and I should get it fixed soon.... I'lltry and take pics to help see where it is coming from, I have a strong feeling it is external of the engine, like the oil cooler lines, as the oil is on the outside of the engine and such, there is NO burning of oil or anything from the tail pipe, it is only from the oil itself dripping on the exhaust system.

Stop by the dealer and get the two o-rings for the oil cooler line fittings. Then just loosen the lines and replace the o-ring on the end of the tubes and re-install. Simple and easy. It only takes about 25 nm of torque to tighten the lines. Just enough to apply sufficient tension so that the nuts do not loosen. The sealing of the o-ring takes little or no torque...just finger tight should do it for sealing alone.

To go back to the main question here, I was going to say this when my internet went out on Friday...

THE NAPA Gold filters appear to have much better flow and more filter area (by increased length of the filter, not cramming more filter media in the same sized can)

So, it doesn't have to be AC Delco. Unless Bbob is paying for it. hahah. AC Delco is the safety net kind of thing. And I'm talking about any part for your GM. If you don't know any better, go with AC Delco...
:deadhorse

Stop by the dealer and get the two o-rings for the oil cooler line fittings. Then just loosen the lines and replace the o-ring on the end of the tubes and re-install. Simple and easy. It only takes about 25 nm of torque to tighten the lines. Just enough to apply sufficient tension so that the nuts do not loosen. The sealing of the o-ring takes little or no torque...just finger tight should do it for sealing alone.

I went to my fathers today and we wuickly looked at it again....

I was telling him about the oil cooler lines and how they can't be over tightened and need a new o-ring, then how you mentioned that finger tight is good enough for the seal etc... but he went in a frenzy that tightening them up woudln't hurt it and that there is no way finger tight would seal it etc....

I need to post some pictures, I havn't even located the leak. The upper oil cooler line seems clean, the lower one is filled with oil (it drips off the bottom of the hose) there is a wire loom in that area, half way up it is clean, below that is it loaded with oil. The motor mount on that side also has oil on it.

My father said it could also be the distrubutor gasket or seal etc... (don't remember what he said)

I parked at school today, not even 4 hours later there were 3 different spots of oil on the ground, I check the level and it has been stable.

sounds like its the o rings where the adapter mates to the engine to me

edit , is there oil on the tranny ?

trans pan is loaded with oil. It is engine oil though, not ATF.

I will make a new thread so this isn't hijacked more :)