Ranger Posted January 1, 2005 Report Share Posted January 1, 2005 Why does cold carbon rap seem to be worse when the car sits for a long period? Anyone else expirience this? When I drive my car every day (which I usually do), CCR seems to be nonexistant. But if I let it set for a couple of days as I recently did while waiting for my blower motor to arrive it is not only present but much worse, the longer it sits unused . This most recent time it sat for about 5 days. After finally getting and installing the blower motor, when I started it, it rattled and clattered like I have never heard before. It also felt like it was running on 5 or 6 cylinders. If I were a potential buyer I wouldn't have even put the car in gear before I ran away. As usual, it smoothed out shortly thereafter and ran fine. I just don't understand what causes this. It certainly is not adding carbon to the cylynder head while inactive. It is almost as if it is swelling like a sponge absorbing moisture with non use. Can you explain this phenomina? Link to comment Share on other sites More sharing options...
Marika Posted January 1, 2005 Report Share Posted January 1, 2005 Quick guess on my part but maybe it's because the carbon absorbs moisture? If you really want to make people safe drivers again then simply remove all the safety features from cars. No more seat belts, ABS brakes, traction control, air bags or stability control. No more anything. You'll see how quickly people will slow down and once again learn to drive like "normal" humans. Link to comment Share on other sites More sharing options...
Scotty Posted January 1, 2005 Report Share Posted January 1, 2005 My guess is that the carbon hardens? I can say this however, I have been taking my Deville on a couple of long trips of say 400 miles about three times in the last month. The engine is using less oil and the cold rap is gone. During those trips I have added many WOTs, the engine seems to perform better when it is pushed hard. Mike Link to comment Share on other sites More sharing options...
JasonA Posted January 2, 2005 Report Share Posted January 2, 2005 It sounds like a classic case of the engine not run hard enough? Mine just set for 2 weeks straight before I finally fixed the leaking hose tonight and it starts quiet as a kitten. Actually, your problem sounds potentially like it's valvetrain-related. I had a Nissan truck (sold it to my brother just last week) that did the same exact thing. If I drove it everyday, like I usually did, it would start quiet. But if it sat for a few days, it would sound like a diesel for a few seconds before smoothing out. Coupled with the fact that yours runs rough for a few, it sounds like possibly a lifter that likes to bleed out while setting. I'd say it could be timing chain tensioner problems, but those are seemingly unheard of on a Northstar engine. Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
Ranger Posted January 2, 2005 Author Report Share Posted January 2, 2005 Jason, I don't run it "hard" very often. Just a WOT blast every now and then BUT, every time I do it, there is no smoke/carbon behind me. Only this last time did it run very, very rough. Usually it runs smooth with the typical piston slap that sounds like a lifter. Link to comment Share on other sites More sharing options...
JohnnyG Posted January 2, 2005 Report Share Posted January 2, 2005 My guess is that it's not carbon at all, but a slow seep of coolant or fuel from a leaking injector into the cylinder. The longer it sits, the more fluid enters. Or the carbon could absorb moisture, but that seems more unlikely. Never underestimate the amount of a persons greed. Link to comment Share on other sites More sharing options...
an01sts Posted January 2, 2005 Report Share Posted January 2, 2005 My thought is that maybe it isn't cold carbon rap. Link to comment Share on other sites More sharing options...
Scotty Posted January 2, 2005 Report Share Posted January 2, 2005 It certainly sounds like your lifters may leak down. What I don't understand is why it takes so long for them to come back up. Maybe they leak down and only a few down come back up fast enough and that gives you a rap until they warm up and stop sticking internally and fill up Link to comment Share on other sites More sharing options...
STYES Posted January 2, 2005 Report Share Posted January 2, 2005 I can, to at least some extent here, agree with all posts to this topic. I would like to add a few things here that all might not agree with, though. I have serviced many a NS, and own one, so I can offer this. The wifes 97 had the same thing, and through a combination of many things, we all but eliminated the "rap" you hear today. First off the WOT procedure is "dead nuts on". The wife never did this, and still doesn't. I have to, and do so once a week, and it is fun. We switched to Mobile 1 synthetic oil. No gains in fuel economy, or oil consumption, but this showed the most improvement in the cold rap, and the darn thing just runs better. Have the "carb clean" procedure performed. Change the plugs even if you do not show 100 grand on the odometer. The wife rarely drives on the freeway, and that is second to the WOT in my opinion. As funny as it may sound, the wife has no clue how to reset the MPG indicator in the info center, so it hasn't been reset in a year. So adding to the WOT, once a week, I do a "loop" around my city via the main freeway routes, some 40 miles. I gain at least 1 MPG in those 40 miles despite the fact that the indicator is basing this info on several thousand miles! Making a long story short here, what I have done has all but eliminated the cold carbon rap discussed here. Initial start up in zero degree weather, and only for a few seconds is all that I can report these days. Considering that we HAD 60 second stints in 30 degree weather, it is a big improvement. Make sure you are using premium grade fuel as well. Link to comment Share on other sites More sharing options...
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