Cadillac CTS First Generation Forum - 2003 - 2007 Discussion, Need Professional and Experienced Expertise in Cadillac CTS Coupe, Sport Sedan and Sport Wagon Forums; Well I have recently bought a 2003 Cadillac CTS 3.2L and I took it to the dealer to have an ...
Well I have recently bought a 2003 Cadillac CTS 3.2L and I took it to the dealer to have an oil leak checked. They told me it was possibly the valve covers as I have seen others speak about on this forum. I asked about adding Mobil 1 synthetic (extended performance)oil and they told me to be sure and not to add any synthetic oil to this engine. Every car that I have had for the last 5 years I have added synthetic oil and never had any trouble. I have noticed other CTS owners talking about adding synthetic oil and they mention no problems. I need everybody's 2 cents because I am confused right now.
i have had synthetic oil in every car ive owned. from a 92 s10 blazer to a bonnevile to a Grand Prix GTP to my CTS. I have yet to hear of it doing damage.. but hell the price of an oilchange has to be alot cheaper at the stealsership if they dont have to use synthetic.
the general rule of thumb i follow with synthetic oil is that once you begin using it, you should not go back to conventional oil. Also, you shouldn't mix conventional and synthetic. Drain all the conventional, change the filter and refill with only synthetic. Also, not sure if you were inquiring about synthetics to fix the oil leak, but my experience has been that the root cause of the leak needs to be addressed, ie broken gasket, over-tightened valve cover, etc. rather then a change to a "superior" type of oil....in my experience
no mine is an 04 3.6. I would read your owners manual...... from cover to cover. I know the 3.6 is based off the northstar platforrm which is a "performance" engine. I have no clue where they pulled the 3.2 from.
Well I looked in the owners manual and found the following paragraph.
"If you are in an area where the temperature falls below
-20F (-29C), consider using either an SAE 5W-30
synthetic oil or an SAE 0W-30 oil. Both will provide
easier cold starting and better protection for your engine
at extremely low temperatures."
They recommend using 10W-30 in warmer climates, which is what I use. But they say you can use SAE 5W-30 synthetic oil in colder climates. I know there is a viscosity difference but if you can use a 5W-30 synthetic would you think I could use a 10W-30 synthetic also? As you can tell I really want to put synthetic in the engine I just do not want to screw it up.
I was a auto-tech and can say your car can't tell the difference between the 2 just that one usually holds up better to heat and other factors.
In fact MOST syn oil comes from the same oil that makes regular oil. It is called a group 3 hydrocracked oil. Just about all Syn in the US is made that way now.
Now if you have a leak then syn will be a waste IMO as you engine is more open to letting in "dirt" so the syn would need to be changed just as soon as regular oil if the leak is pretty bad. if not then you could use a 10w30 syn and sun that till it is fixed.
The only car i have seen that the maker said not to use syn was Mazda RX7/RX8. Thats because the wankle motor uses oil because of its type of seals and some syn did not burn very well. Other then that most cars and even trucks have a oil that will work in syn formula for them.
Sorry but I gotta correct a few things in this thread.
First off the HF 3.6 is not based on the Northstar V8. There was a 3.5L "Shortstar" used in the Olds Intrigue and Aurora for a few years based on the Northstar, but that engine was expensive, and not that reliable and got axed.
Secondly there is no harm in mixing ANY oils. Different brands, different types (regular & synthetic), different viscosities. I'm not saying I recommend it, because the detergent adds, viscosity modifiers, and anti wear ingredients that each oil has may or may not compliment each other well. Some oils features lots of Na, other lots of Zinc, or Molybdenum.... getting a little of each may be slightly worse than sticking to one chemistry in particular.
Nonetheless the idea that you mix two and will cause major engine damage is false.
For example, every oil company out there sells a synthetic-blend these days.
If you're leaking, and running regular, I wouldn't switch to synthetic unless you're ready to truly fix the leak. Synthetics will tend to clean the gaskets more, which will dislodge small dirt particles stuck in gaskets, preventing the leaks from getting worse. You dislodge that sludge and they may pour.
If you're not leaking at all, feel free to switch.
Final point: today's regular oils aren't nearly as low on the totem pole compared to synthetics as the situation used to be. The stock oils are quite similar and there's very sophisticted add packs in each. Whereas it used to be that a regular oil lasted 3000 miles and synthetic perhaps 10000, today's good dino oils can go 7000 miles in certain engines, under certain use. The gap between the two is shrinking.
If you want to learn a LOT more, spend a few weeks at www.bobistheoilguy.com just reading. Lots of chemists and engine experts and you will learn more than you ever dreamed.