Rods knocking on start up!

[Dave84]

This has been going on for a while but is getting worse lately, when ever my merc hasent been running for a couple hour's or over night when i start it the rod's knock for at least 15 seconds, i did an oil change a couple months ago, went to canadian tire told them what i needed oil for and they gave me 5 W 30, im not sure if that kind of oil is to thin?? My car only has 160,000 Km's on it, so i hope it's nothing major, the engine runs nice and quiet after that 15 seconds though,,.

[Blaze86Vic]

5W is too thin, unless it is really really cold. I'd run 10W, and if your engine is nockings maybe even 15w

[Mercmarquis]

5w is a bit thin, Hopefully runnning a thicker oil will make it go away since its only for the first 15 secs

[gadget73]

Ditch the 5w. We fixed Fordgirl's Vic with 20w50 and a quart of Lucas. Engine is nice and silent now.

[87mefull]

:stupid: For now, I'd run 20w50 like gadget said since its still summertime and it may help alot. For the winter time I would drop to 15w40 or 10w30 with an additive. Running an additive is a great idea, I used both rislone and lucas in the past and both would make the knocks and valve chatter disapper.

Also, its pretty normal for a high mileage 5.0 to have low oil pressure, so on a cold morning it may still have a slight knock. Seen plenty of these motors see 200k or better with a low oil pressure and even a slight knock. When your engine light comes on and you have a constant 0 psi at idle, then you have a problem.

[87_crown_vic]

if anybody has the original owners manual, it says to use 10w30 or thicker for all season. just thought i would add this since i have mine. i have been also told that with higher mileage it is better to use a thicker oil.

[gabegt90]

I always use 10w 30 and rislone

[Southern_Pride]

15w40 here and no rattles. Also I use a smaller oil filter as it takes less time to fill up. I think its a motorcraft fl400.

[grandpaslincoln]

10W 30 here

[turbo2256b]

Had a big meeting at Ford power train and told us to never use 5W it was just to meet fuel economy and shouldnt be used in there engines.

[Archangel]

Well that's simply great, I've been running 5W30 for over an year now. Never had a problem with knocking though, only slight valve chatter sometimes but it's intermittent.

[Dave84]

ok ,, So shuld i use any additive's for 20W 30 then if i get that kind of oil?
Thanks

[turbo2256b]

I have used Shell Rotilla T for years in most of my cars 15w- 40w. This is now one of the few oils that will still support flat tapet cams. Of course most of us run rollers. If you need something a bit thinner for the winter add a quart or two of a synthetic in it.

[Dave84]

ok thanks guy's

[Southern_Pride]

I am a firm believer in rotella-t also. I go like 8-10k between oil changes with it.