What can i do to help fix oil burning?

Asked by May 22, 2013 at 10:40 AM about the 1985 GMC Sierra

Question type: Maintenance & Repair

It is a 1985 GMC Sierra Classic, that burns quite a bit of oil. I just changed the oil a couple months ago, but i have to keep adding oil to avoid burning up the block. It has always had the problem since i got the truck but here recently has been getting worse. The engine is a 305 V8.

6 Answers

Mileage? You may have simply worn it out, needs rings or valve guides, especially if you notice smoke upon start up. A 1985, if original, has served you well and has just lived it's life span.

3 out of 3 people think this is helpful.

Well said Dave, and if your burning more than a quart every 500-700 miles it's time for a rebuild if you don't notice anything leaking. How are the valve cover gaskets?

3 out of 3 people think this is helpful.

30534 miles, but being an older truck i imagine the odometer has flipped at least once especially since it is my daily driver. There is a knocking in the engine itself which i believe is a lifter or a rod starting to go out, and it smokes terribly when started and usually doesn't stop until it's reached it's normal running temp (right around 200 degrees or so, been a while since the temp gauge has worked properly or even at all most times). There is no leak though i have checked for that and i know it's burning the oil because 1. the smoke is blue and 2. when the oil cap is removed after running for a while smoke pours out of it.


If you have a knocking and blue smoke, it's either time for a rebuilt motor, or a junkyard motor. Not worth rebuilding the current one. Selling it is also an option.

2 out of 2 people think this is helpful.

If you lived close to me I could give you a '79 305/7 with low miles. Not worth selling. As Tom said just check your local adds 305's are very cheap, everyone wants 350's. If it's a junkyard motor I usually want them to start it and show me before I buy it!!


quote:DavidH25 (Mileage? You may have simply worn it out, needs rings or valve guides, especially if you notice smoke upon start up. A 1985, if original, has served you well and has just lived it's life span. ) I have to agree. You can get the head's redone for around $150.- $250 that should take care of the valve guides valve seals. If you get a used motor then you have the head done and ready work. The 305/350 around of the 80's where known to have guides go bad now and then and when mile got up a bit.

1 out of 1 people think this is helpful.

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