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Before the engine reaches operating temp it makes a slight clattering noise at idle. After it warms up it goes basically totally away. What could this be? It runs fine, but does put out a cloud of blue smoke at start up occasionally. Any ideas? Thanks
check your exhaust manifolds. look at the studs/nuts to see if your missing any, or if some are loose..
without actualy hearing whats gongi on, its hard to say what it is.. but a exhaust leak when cold will usualy seal up when the engine gets hot if its not to big.
Its def not exhaust related. We got all the broke studs fixed. I tried running 10w-30, 5-30 and 5-20 in it, but it doesnt make much difference. The noise cannot be heard while driving but is really noticeable at cold idle. When teh truck was bought it did not have an air filter in at all. Also looking down the oil fill tube, you can see some sludge and build up... It has done this as long as we have owned it.
On this oil change with the Motorcraft 5-20, it is using a quart every 600-700 miles. It used about a qt to 1000 before on 5-30. It does smoke some sometimes when you start it but none at all when it is running.This poor old truck has really been through it. It didnt have a air filter when we bought it, but couldnt see much dirt in the intake so I dont think it had been out long. THey said it had just been serviced so maybe they just forgot to put one in when they changed it. Then I changed the sway bar bushings and put the sway bar on upside down and it hit the oil pan and cracked it. It was drove mabee 2-3 miles without any oil. I just noticed the guage was down but couldnt tell anything at all different with how it was running. Pulled the pan and fixed it and while it was off I looked at the cylinder walls and believe it or not they looked great! You could see the cross hatches really good and I couldnt see any grooves or scaring. It has always made this clatter at idle and it seems it has got just alittle louder over the 15000 mi we have put on it but not much.
Using a quart of 5w-30 in 1k miles is excessive in my book but still within Fords acceptable range. If the valve seals are not in the greatest shape you can get a puff of smoke at startup. The modulars have also been known to produce a puff of smoke on startup sometimes if the truck is ran for a minute or two and shutoff, then the next time it start it you'll get a puff, but its fuel. I would try to replace the PCV valve to see if that helps you consumption. Running a full synthetic oil will help to remove any sludge in the engine but the engine will consume more synthetic than reg dino or blend. Sounds like that engine has shure been through a lot.