NOW i have a knock.....

Messages
258
Location
IL
i just changed my oil today... switched from mobil 1 10w30 to mobil 1 15w50...with supertech filter. Now the car knocks...whenever. No leaks, oil full, everything seems fine... happened RIGHT after the oil change. I have a hunch its the super tech? since it has the rubber thing over the small holes,(antidrainbackvalve?) maybe its restricting flow or something... never had knocks with the delco PF58, which has no rubber blocker under the holes... any suggestions? It seems to be coming from the underside of the car...like a bottom end knock, cant hear it in front of engine, mostly when i open the door and lean over...
 

Patman

Staff member
Messages
22,012
Location
Guelph, Ontario
The antidrainback valve should not cause a flow restriction, maybe you just got a bad filter. Try putting on a Bosch premium, the PF58/59 equivalent is the 3423.
 

eldawg4100

Thread starter
Messages
258
Location
IL
it may get worse when the car is warmed up. i pulled out the dipstick while the engine was running and the oil was like water... so, its not a case of the temperature.....
 

MolaKule

Staff member
Messages
21,950
Location
Iowegia - USA
What do mean, "Like water?" Oil is thinner when hot, but a 15W50 is not thin as water. What is your oil pressure. As suggested, change oil filters.
 

eldawg4100

Thread starter
Messages
258
Location
IL
92 seville SLS.... no way to check oil pressure on the dash or anything. no gauge I am going to put in the PF59 I have laying around. if that doesnt cure it, I will be forced to go pick up some 0w-30 or 10w30.....
 

eldawg4100

Thread starter
Messages
258
Location
IL
judging from the comments in the forum, it should be totally fine.... car sits in a garage overnight that stays at about 40 degrees. i forget... i didnt use the super tech, I used the delco PF59... the car is a cadillac calling for pf-58.... although, the posts in the oil filter forum said its ok to use the 59 for 58 applications. maybe the anti drain back valve on the 59 doesnt work to good with this engine....
 
Messages
948
Location
st. Louis
Are you sure the knock wasn't there before? I agree that trying another filter should be your first step. If the filter is indeed restrictive, you need to get it out of there. If you check the specs for M1 15W-50 on Mobil's site, you find that the pumpabaility limit is about -30degF....no worse than a petroleum 5W-30. So though it may not be ideal, doesn't seem the makings of a catastrophy.
 
Messages
3,023
Location
USA-Michigan
Never mind if 15W-50 is said to be ok, its what is the right oil for your car. If 10W-30 is what you are supposed to use, then use it. GM vehicles are not designed for a 15W-50 oil. That a racing type oil and would not be approiate for normal vehicle.
 
Messages
885
Location
North Carolina
If the knock actually started right after the oil change, it sounds more like some oil passage got physically plugged/clogged/restricted , is it possible any crud/dirt or whatever either fell in the oil fill or funnel maybe? I have seen some filters that had metal shavings in the threads area that could possibly be initially on the "clean side" of the filter and be pushed unfortunately immediately into the motor...GM motor right? the oil filter bypass is just before the filter, rather than in the filter itself, possibly it was stuck closed and the new oil (any new oil is thicker at cold crank than after even 1 minute of run time) was unable to bypass the filter on that first cold startup? good luck.. Rando
 
Messages
2,480
Now your talking....!! I had the EXACT same things when I first used M-1 Tri 15W-50 after switching from BMW 5-30 and previously 5-40 after 100k mi. because I was noticing sludge build-up under the oil cap area....and my owner's manual specs. this oil to be ACCEPTABLE at temps. OVER -4F (-20C)!!! And I don't they were talking synthetic here... My take: Years of inferior water-like 5w-30 oil leads to sludge build up which now acts like an 'interference' in the engine when thicker oil is used. Your Caddy should have an OHC engine, no? Anyways...I made the switch (from BMW 5w-30) this past summer (100F - didn't matter though)...engine freaked out...ticking...check engine light at every second start-up, slugginsh driving, etc....drained and used Delvac 1 5-40 for 3-4 k mi...when I noticed immediate cleaning of the area under the oil cap....also...consumption as this occurred...and increased engine power...kept topping off with the M-1 15-50...second and now third change has been with 15-50 with no problems except for when temps. are below 30F (OC) and tick occurs for 2 seconds and then goes away...guess there's still some s**t in there...still haven't decided on whether there is harm being done...but I'm riding it out...letting things clean out (a little longer than with Delvac...).....good luck...may try the Delvac first...
 

eldawg4100

Thread starter
Messages
258
Location
IL
filter was clean... i just drained that stuff, it is actually pretty thick even when hot, i was surprised since the stuff on the dipstick was like dripping off at a fast rate... well at start up after adding mobil 1 10w30, it knocked pretty bad for about 10 seconds... this happened before when i changed from dino oil to synthetic... i think the knock may be gone, havent really heard it since that start up (only drove it for 10 minutes though) the caddy 4.9 engine i have is OHV pushrod 16valve engine...high compression, it needs premium...
 
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