Car knocking when cold.

syphon

Registered User
Hey everyone. My car has been knocking while it's cold for a while, and I want to see if you guys think this is a problem, a MAJOR problem, or something that's just gonna happen.

Whenever I start my car in the morning, it knocks. I can't hear the knocking that much when it's in park, but once I put it in gear, it's really obvious. It lasts longer than I'd expect for a cold knock. Even if I warm the car up for a good 20 minutes, it'll still knock until I drive it around for 5 to 10 minutes or so. After then, the car sounds smooth (unless you count the stupid alternator bearing noise or the vacuum leak I can't track down).

I'm having issues with my thermostat, so the car has been running colder than usual lately.
http://www.sccoa.com/forums/showthread.php?s=&threadid=17372
Could this be causing it? Is the engine temp too low initially... causing it to knock?

Another issue I should mention is the Oil Pressure gage. When I changed my alternator, suddenly the Oil Pressure gage says there is no pressure. After careful diagnostics, I figured that I whacked the sending unit when I used a metal bar to pry back the belt tensioner in the alt. swap.

The knocking was still there BEFORE the oil gage mess up, so I'm pretty sure the oil pressure is still fine, the gage is just broken. The oil isn't leaking or burning (last oil change the car still had 4 1/2 quarts in her).

Is this a major engine problem, or something related with the temperature? or something else? What do you guys think?
 
I had a similar problem with my SC before my HG's went. It would always knock and take for ever to warm up. You say you have a vacuum leak since ive redone my head gaskets ive had no knock at all. I would say you need to find that vacuum leak and fix it. Before my HG went I had a vacuum leak a very small one at my IC tubes when i redid the HG i sealed them up better and since then not a problem. Ive noticed that on these cars even the smallest vacuum leak can cause problems like that.


just my .02
 
The vaccum leak never caused any problems, other than a hiss. When idling I get about 18-19... uhhh, psi? i forget what the measurement of vaccum is.

Also, I'm pretty sure the HG's have been fixed in the last year or less.
 
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