I have a 77 250 4x4 with a 400. Bored .30 over. Rebuilt about 7000 miles ago. The cylinder heads were just redone (200) miles ago. A poor cylinder head rebuild by the previous owner. The truck is running great, no smoke, no leaks, etc. I hate to complain but it seemes that every third or so fill up (16 gal. tank) I am adding a 1/2 qt of oil. (Valvoline 30W) per my mechanic. Is this normal? If so, I am OK with it, just want to make sure I am diligent in her care. Any thoughts would be appreciated. 77hb

P.S. Thank you to those who responded regarding richening the fuel mixture post. Plugs are a nice tan color now and truck is running strong.

 

Moved to proper forum.

No that is not normal.

 

Are you showing any signs of burning oil? Some blue smoke when first starting up. Have someone follow you around for a while and note if there is any oil burning going on. Bad or missing valvestem seals can cause this problem. Had a similar situation. Had to ad oil about every 150-200mi. Plugs looked clean. When I finally pulled the heads, the back side of the intake valves were coked up with carbon. Oil was being sucked down the valve stem. Talke to the guy who did the heads and ask about the valve guides and stem seals.

 

Thank you for the advice. I know the seals were replaced, because he mentioned that they had used the wrong seals the first time. I will follow up with my mechanic and post any findings. 77hb

 

knurled valve guides can allow more oil consumption than you'd like. the old rule of thumb being "1 quart per thousand miles" isn't far off from the consumption you are describing, but i think you are on the wrong side of the rule? are your valve covers baffled where the PCV is? unbaffled covers can allow the PCV to draw oil out of the engine. no leaks?

 

OK....I'm going to venture out on a limb here because I have absolutely no hard data other than personal experience to back it up.

First tho' a question: Are you adding oil because it's half a quart below the Full mark or because it's actually showing half a quart below the Add mark?

For whatever reason IC engines regardless of brand tend to seek their own oil level. On an engine in good condition that isn't burning or leaking oil I have found that after an oil change I can fill the oil to the Full mark, run the engine for a few minutes, check for leaks, let the oil drain back into the pan and top it up to the full mark again. After a few days of running the oil level will be back to somewhere between the Add & Full mark again but it won't drop past that. By the time the next oil change rolls around it's still around the Add mark. I've done this with many motors of various brands over the years and as long as they're in good shape they all seem to do this.

I don't know if I explained that very well but the point I'm trying to make here is if the oil is showing half a quart from Full leave it alone. Check it regularly and make sure it doesn't drop below Add but don't top it up to Full until it reaches the Add mark.

 

I am not sure what valve covers being baffled means. I showed my PVC valve to the Autozone guy who seemed to think it was OK. (for what thats worth, meaning I wouldn't know any better). I am adding oil when it is at 1/2 way below the full mark. The last time it was at the add mark and added 1 QT. I have not waited to see if it would go below the add mark. Under the truck today, and very little signs of oil leaks. Nothing hitting the driveway overnight or nights. Please let me know about the valve cover baffling and I will wait to see if the oil falls below the add mark. As always, Thanks 77hb

 

it's not that baffling. baffles are like shrouds or guards inside the valvecovers that keep the oil mist from being able to be sucked out too easily. stock valvecovers have baffles in them, if you look into the hole in the cover you can see metal walls that go down almost to the head. some aftermarket valvecovers have baffles, some don't. if you can look into the hole and see valvesprings they don't have baffles. a guy i know eliminated his engines excesive oil consumption by changing his valve covers to baffled ones.

 

What bill is suggesting is don't add oil until it is at the "add" mark and the problem might go away. Filling halfway between add and full might be considered 'over filling'.

Peter

 

grclark, thank you for the response and the explaination. I will check in the am light and let you know. The valve covers are aftermaket and very may well be baffle free. I will post tomorrow and let you know. Thanks, 77hb

 

Replace the PCV valve while you are at it.

 

The valve covers are baffled. I will get a new PCV today and we will wait to see if the the oil holds at the add line. Thanks for everyones help. I will update on the add line results. Thanks 77hb

 

sometimes a heavier weight of oil helps some. sometimes the baffles in aftermarket covers aren't as good as stock ones too, do you have stock covers to compare yours to? if not you might find a decent picture on Ebay.

 

The oil level did not hold at the add mark, so back under the truck I went for leaks. It appears that there is a leak on the oil pan at the dipstick. The oil leak then runs back to the tanny housing etc. I don't know if the leak is enough to account for that much oil loss, but it needs to be corrected none the less. Where the dipstick enters the oil pan, there is a nut. I attempted to tighten and felt tight (didn't want to strip). So I guess my question would be, is the next step to drop the oil pan and check. If so, any advice before I begin. I am a novice mechanic trying to learn as I go.

P.S. For those that I told there was no leaks, I apologize. 77hb

 

clean oil is hard to see. the good thing is that you're on it.