: Loud ticking at idle.



Olds195
02-02-10, 03:42 AM
I currently have an 03 Olds Aurora. I am aware that this isn't a Caddy...but the 4.0 is close enough to the N*. Anyways, a loud ticking develops around the front lower half of the engine (its louder underneath the car) after the car is well warmed up, and the oil pressure falls below 35psi. The oil level is fine, and the oil pressure seems normal while in operation. the "Oil Life" gauge has 90% of the life remaining. I am currently using 20W-50 oil in the car. This is the first oil change I've used this weight. I am aware that the manual basically says not use anything above 10W-30, but the car has used no oil since it was changed to the heavier weight, which was around 700 miles ago. I use it in my other vehicles, and since it rarely stays below freezing for more than 12 hours at a time, I didn't think it would cause any problems. Could the oil be causing the noise, or could it be something else? The car also mainly sits parked, and is only driven in spurts.

99Classillac
02-02-10, 10:47 AM
So you are using heavier weight oil in a car in cold weather and you drive it in short spurts? Why? I would have gone with a thin oil in cold weather. Especially if you aren't driving it long. The motor and the oil has to heat up before the oil gets thinned out. Strain on the pump and stuff. Thinner oil is a better choice.

Submariner409
02-02-10, 11:39 AM
You should not, under any circumstances, use motorcycle or heavy diesel engine oils in your 4.0, or any other automotive passenger car engine, for that matter. 20W-50 is way too heavy an oil for that engine and is specifically NOT recommended by GM. Read your owner's manual.

Use the recommended oil for your ambient temperature range (10W-30 ?) and do some listening to locate the tick. GM engines will run about 10-20 psi oil pressure at hot idle and around 35-45 at cruise (over 2000 rpm).

(BTW - that 20W-50 oil is destroying your engine during cold starts due to low oil flow. Your short hop driving is also an engine killer: a car engine experiences less wear during a 3,500 mile coast-to-coast trip than in two weeks of city stop & go.)

Ranger
02-02-10, 01:11 PM
This is the first oil change I've used this weight. I am aware that the manual basically says not use anything above 10W-30, but the car has used no oil since it was changed to the heavier weight
So what if it uses a little oil. Read the Technical Archives at the top left of this page regarding oil consumption. It's not as bad as you seem to think.

MisterBlue
02-05-10, 11:39 AM
The 20-50 is only good for a motor that's plumb wore out. It's WAY too heavy for a close-tolerance, low mileage motor. The thicker oil takes a few seconds to start circulating (especially in cold weather) and this is terrible for bearings, rings, and valve guides. The engine will probably see as much wear in a few dozen real cold starts as it would normally see in a 100k of driving.

It sounds like your rod bearings might be telling you that. :suspect:

I make it a habit with a Northstar to never add oil unless it's well over a quart low. Adding oil when your engine is down a half-quart may make you feel good, but it ain't doing very much for an engine that has 6 quarts or more left in it. When I started putting only 6 1/2 quarts in my STS at oil-change time, the level hardly moved between changes.

Submariner409
02-05-10, 12:06 PM
:yeah:

..........and your fill procedure is close to the recommendation to fill to halfway up the dipstick hashmark: Keeping the level at the top mark promotes oil consumption. My engine takes a tad over 7 quarts, with filter, to fill to that level and I use a quart of Pennzoil 5W-30 Platinum every 4,000 miles+.

auroradude
02-09-10, 11:15 PM
what about 10w-40? i've been using that in the winter. is that really bad? I have a ton of miles on the motor though...

Submariner409
02-09-10, 11:46 PM
Depends on the engine, and what's a "ton of miles" ?

10W-40 is good for vintage Olds 455s, GM 454s; good ol' iron stump-pulling engines. OR a modern engine that is subjected to RV or trailer towing duty.

Consider that Ford is recommending 5W-20 year round for their engines - both car and truck - and take into account the lubricating properties of modern oils and the old "heavier is better" theory goes out the window. My F-150 4.6L will go round trip to Florida (1675 miles) and not use one drop of Pennzoil Platinum 5W-20. (The damn thing uses so little oil that I get antsy and dump some Marvel Mystery Oil into each fillup on highway trips - upper cylinder lube.)

Heavy oils actually promote cold start wear due to low flow, and if the car is a city driver, they never warm enough to flow properly.

Blah, blah, blah...........read the oil company spec sheets..........

auroradude
02-10-10, 12:10 AM
for my northstar. 146k miles. I've been using 10w-40 for the last couple years (even in winters), so i hope it hasn't been hurting anything. But the winters here rarely get below 32 degrees..

Submariner409
02-10-10, 12:39 AM
You're borderline OK, but take a look at the recommended oils on the "thermometer" in your owners manual.

West Chester ? Got your snow shovel ready ? ..........and you have been to about 12 degrees this winter, so far..........

97EldoCoupe
02-10-10, 12:52 AM
What everyone else said. 5w-30 in your 4.0. The specs changed with the roller cam upgrade in 2000. Stick with a good brand of the factory recommended oil type. Avoid the 99 cent stuff- if you go cheap you get cheap and it can cost you in the long run. A bit of oil usage is a good thing. These damn engines never wear out - so long as they have oil in the crankcase.

auroradude
02-10-10, 12:59 AM
Do you think its causing a lot more wear at startup than the 10w-30? I will change it out in about 2k miles for 10w-30. I currently have 1k miles on an auto-rx treatment so i really don't want to waste all of that. I used Castrol GTX 10w-40 btw, I never use cheapo stuff.


Yep, i have my 9hp snowblower ready if thats what you mean!! It plowed right thru all 22" last time like it was a chocolate cake

97EldoCoupe
02-10-10, 01:02 AM
Stump pulling engines Sub? :D Speaking of which- we still have a horse trade to make- please send your address again to my email- jwiebe@northstarperformance.com and I will get that intake and injectors out to you. Sorry the fuel rails are totally different than the STS models- I think these were meant for the last Eldorados. The intake and injectors are on the shop if you can track down a 76 455 Q-Jet rebuild kit somewhere in your travels. No rush at all.

Sorry to get off topic-

Ranger
02-10-10, 05:37 PM
Do you think its causing a lot more wear at startup than the 10w-30? I will change it out in about 2k miles for 10w-30. I currently have 1k miles on an auto-rx treatment so i really don't want to waste all of that. I used Castrol GTX 10w-40 btw, I never use cheapo stuff.


Yep, i have my 9hp snowblower ready if thats what you mean!! It plowed right thru all 22" last time like it was a chocolate cake
No, their both 10W when cold. I still use 10W30.

Olds195
02-15-10, 10:23 PM
To resurrect an old post...I changed the oil out, 5W-30....And I thought the noise was gone...but only just for a little, after driving it around today, the tick it still there. I only drove with the heavy weight stuff at most 700 miles. Since I have owned the car (3 years, and about 25,000 miles), I have normally used 10W-30, that was the first time I switched to the 20W-50. Have I done irreversible damage or is it just a coincidence? P.S. My oil pressure has never fallen below 20psi at idle, the average is about 28psi at idle after its warm, and its around 60psi at cruising speed. This has been the same since I've owned the car, I only noticed an increase of around 2psi with the 20W-50...is that normal as well

Submariner409
02-16-10, 09:17 AM
It is very doubtful that you did any engine damage by running motorcycle oil in it. Forget the past. Your observed oil pressures are perfectly normal; here's why:

The lubrication system has two "safety valves": one is in the filter itself, consisting of an internal bypass which allows full oil flow even if the filter element is clogged. (That bypass was probably open most of the time the heavy oil was in the engine - physically impossible to push all that oil through the filter element, especially when cold, so the filter dutifully bypasses the media.) The second is in the oil pump itself: a pressure control valve (relief valve) which sets maximum oil pressure - in your case, 60 psi. Even if you had run 80/90 gear oil your pressure would have stayed at 60. (Maybe a tad higher when cold.) The excess oil is returned to the pump suction side by a drain channel downstream of the relief valve.

Why limit passenger engines to 60 psi ?? Oil flow is what lubricates an engine, not pressure. Pressure is due to the resistance of the oil to "squirt" out of bearings and passages. Automotive engine oil pumps, even stock, move incredible amounts of oil through an engine so there must be an internal pressure relief or we all would have leaky engines and burst filter cases. Pressure is necessary and goes hand in hand with flow, but high oil pressure does not mean good lubrication is occurring. Low oil pressure (at idle) does not mean that good lubrication is not occurring; that simply means, at idle, the volume of oil pumped is less than that which squirts out of the bearings and passages, so pressure must drop according to the laws of physics.

Engine lube oil systems can be thought of as a "leaky hydraulic system" as flow and pressure vary with pump output and work (oil movement) accomplished.

For many years GM seemed to like an upper oil pressure limit of 45 - 50 psi while Ford liked 50 - 60 psi. Now everyone seems to be in the 50 - 60 ballpark. A "high pressure" oil pump is nothing special - it merely has a slightly heavier spring in the relief valve/ball passage.

Concerning your "tick" - is there any chance you have either an exhaust manifold gasket or manifold flange gasket leak ? Either of these will produce a distinct "tick" with (sometimes) "soft edges" to the sound: pffftt, pffftt, pffftt, pffftt.

Olds195
02-16-10, 10:03 PM
Concerning your "tick" - is there any chance you have either an exhaust manifold gasket or manifold flange gasket leak ? Either of these will produce a distinct "tick" with (sometimes) "soft edges" to the sound: pffftt, pffftt, pffftt, pffftt.


I am actually beginning to think that it is something of that nature, because its not a constant tick, it isn't with the timing of the engine, and does not do it at all when the engine is even slightly revved. After listening to it closely, and for a while, it really doesn't even sound like its internal, but somewhat external.