I have a 350 gmc propane motor. It burns oil "only when going down hill". I'm going to do a compression test today. Is this definitely the rings, or could it be valve guides, valve seals, intake manifold etc. I have to add oil about once every 4000 kilometres, which isn't a whole lot. Any help would be appreciated.
"bob" wrote
How much oil in 4000 kilometers? If you are talking about one liter, I wouldn't bother worrying about that. In fact, you can consider yourself quite lucky.
When you say, "it burns oil only when going down a hill" I assume that you mean it smokes when you go down a hill with your foot off the throttle. A good indication that you are consuming some oil through the valve guides/seals. And depending on the year of the engine, there were issues with the intake manifold gasket sucking oil into 6 and 8 cylinders. But that was a number of years ago.
Ian
In article , violet-lightening- snipped-for-privacy@hotmail.com says... .
Yes, I am talking about one litre
Again, that's exactly what I mean. My rebuilt motor is only 15,000 kilometers old, and I see blue smoke coming out my exaust, only down a long steep grade, and only with my foot off the throttle. It is under warranty, however I have to pay my friend $500.00 to take it out and put another rebuild in "since it wasn't his fault". Again I am going to do a compression test and I'll let you know the results. But your opinion that it's probably a valve guide and not a ring makes me relieved, but I'd also like to know why you came to that conclusion. Again, you,ve made my day :-)
"bob" wrote
Again, I'll repeat....this is quite normal oil consumption. Especially for a rebuilt engine that you probably have little idea of the actual quality of the rebuild procedure.
If you attempt to return the rebuilt with the complaint of
1 liter of oil consumption in 4000 kilometers, I highly doubt that the rebuilder will consider warrantying this.I would agree....it has nothing to do with him. Unless he happened to assemble the heads, but it sounds like it was some sort of drop-in motor. And of course, it would be unreasonable to expect him to R and R the motor for free because of normal oil consumption.
Guides and seals are the more likely culprit when the engine is being operated in a high vacuum situation....(driving down long grades with foot off the throttle). Who knows how they rebuilt the heads on this engine. Who knows what style of seals they used and if they installed them correctly. Rebuilt engines are always a bit of a gamble.
Ian
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.