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View Full Version : How much blow by is " a lot?"



84K2500
01-04-2010, 09:29
Hi Folks,
bought an 84 K2500 6.2 J-code, manual tran. Truck runs great, starts good cold and hot, good mileage, etc. I was told that the 92000 miles on the odo was actual, was owned by little old man, was never worked hard, etc.

So, I checked the oil about 2000 miles since my last oil change and it was a quart low. After reading around here it seems valve seals aren't likely to be a problem, so I did the blow-by test. Warm, with the oil cap off there is a steady series of "puffs" coming out of the tube. It isn't a constant stream, but does continually puff in pulse with the idle. :confused:

Is this normal for a low mile 6.2 or do you think the odo was rolled over? In any event, how bad is "bad?"
Thanks for any help you can offer....
84K2500

JohnC
01-04-2010, 11:42
...So, I checked the oil about 2000 miles since my last oil change and it was a quart low. After reading around here it seems valve seals aren't likely to be a problem,...

What problem? A quart in 2000 miles is fine. None of my 6.5's nor the Ford ever did that good.

84K2500
01-05-2010, 08:37
Ok, Thanks John, that is encouraging. I checked my service log and it is more like a quart in 1600 miles. So that is OK? This is my first diesel, will probably have more than a few noob questions. Sure am glad I found this site...

JohnC
01-05-2010, 09:33
...it is more like a quart in 1600 miles. So that is OK?

In my opinion, perfectly fine. My Ford, my '93 and my '95 were broken in by 3 different people and each one used about 1 quart in 1200 miles for all of their lives.