Using Oil, How much is too much??

[1990SilveradoK5]

I don't want to have to tear into my recently purchased truck unless necissary, but here is what she's doing.

Last week on the way to work I noticed my oil pressure going up and down like a rollercoaster, found that the oil was low. That night I did a full oil change including filter, no leaks that I can find, and no puddles on the concrete. One week after that oil change she's a quart low??

I have noticed that when she's cold she will smoke if I Smash the skinny one, but during normal driving she doesn't.

Pulled her into the garage Sunday after driving her 25-30 miles and noticed directly out from the exhaust pipe, a splattering of black moisture. Doesn't seem to be "oil" atleast prior to the combustion chamber, why doesn't she smoke all the time if she's burning that much oil?

Would valve seals help?? I don't want to pull her apart as she is my daily driver, and my wife would [censored] if I told her the truck I just purchased needed anything expensive. The DPO said and I quote "It uses 1/4 of a quart per oil change" well I know thats BS now.

Oh, bye the way, 1990 350 TBI Silverado

Thanks in advance.

Gone Large and Loving It.
Keith

 

[Emmettology 101]

With only 1/4 quart you should be fine. Hell, the last 305 I had in mine burned about 2-3 quarts between changes.... It ran fine, but was just down on power...

If it smoke in the morning, that would be your valve seals.. But smoking while you are driving, i would think that would be the rings.....

A quarter of a quart isn't that much to be burning between changes. Just keep an eye on your level...

Mike

See <font color=green>EMMETT</font color=green> -&gt; <A target="_blank" HREF=http://emmett.coloradok5.com>http://emmett.coloradok5.com</A>

 

[Butch]

Oil consumption is considered excessive when you use more than one quart per 800 miles. That seems like a lot to me, but that is what is reguarded as excessive. If your motor has a lot of miles you might get by with replacing the seals, but dont try to rebuild the heads. Many times with an old motor if you rebuild the heads you gain enough compression that the old bottom end can't take it and you end up with a blown motor. During warm climate you can run straight 30w and it should help with the oil consumption. Worst case blame the guy you bought it from as screwing you to help explain it to your wife. Long ago I began to ignore my wife about my Blazer and the money I spend on it. If she complains too much take up to her closet and discuss her shopping LOL

I thought I was wrong once,
but I was mistaken

 

[Gandolf]

My '89's 350 has 149K miles on it. It runs very smooth, there are no leaks and I get a mild puff of blue smoke when I start it cold. Oil use is 1 quart every 3,500 miles.


'89 K5 Silverado..."You can’t have a real adventure, unless the outcome is truly uncertain".

 

[dyeager535]

Keith, I don't want to insult your intelligence, but did you fill the filter before doing the oil change? I believe most of them can suck up about 1/2 to 1 quart of oil. If the truck isn't smoking, nor leaking, the oil just isn't leaving the motor! May sound overly simplistic, but unless you have a cylinder that is dead (you'd have a relatively rough idle) you will be burning the oil, or leaving a goodly sized puddle on the ground, bellhousing would be dripping, etc. VERY little oil will produce noticeable smoke. A few drops of oil will produce a fairly good sized oil spot too.

Smoking on hard acceleration even when warm should be rings, smoke on startup is valve seals, which is not really very detrimental. If you ask me, that extra cylinder wall coating at start up is good! : )

I once had a Cutlass that used 2 quarts of oil every 50 miles. Had a hole in the piston. I'd consider that excesive.

Dorian
My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>

 

[1990SilveradoK5]

I agree that 1 quart in a week is excessive.

The engine has 125,500 miles on it, it runs great other than the question of where my oil is going?

What does it take to do a set of seals? Time? $$? Of course I will wrench it myself.

It does have an aftermarket cooler of some sort hanging under the radiator, have not traced the lines to see if it is for the tranny or an oil cooler.

(The 1/4 quart was what the owner told me not what it is using)

Gone Large and Loving It.
Keith

 

[CaptCrunch]

I figure it is kind of an opinion thing. There are guys running buckets that take a quart a day and smoke blows out like it was on fire. The best way to see how bad the rings are is to compression test each cylinder and then squirt in a little bit of oil and test again. If it goes way up the rings are shot...usually a change of 10 or 20 psi is acceptable and a total compression of 90 or more is ok. Also just in my wrench experiences at the shop I find the #8 cylinder is the weak in a lot of these trucks... Probably because it is one of the worst to get at (although it's still cake compared to the newer stuff).
Good luck... especially w/ the wifey... we all know how that goes LOL

1987 Chevy K5 Blazer- 350 TBI

 

[1990SilveradoK5]

I might not be as knowledgable about the workings of my K5 as many of you are, but I do know how to change my oil.

I am not afraid to tackle much of anything, as long as I have an outline or manual to follow.

I will do a compression check sometime this week and see what that tells me. However I don't think it is the rings as I have never seen it smoke after it is warm.

Gone Large and Loving It.
Keith

 

[CaptCrunch]

You never said how many miles were on it... Generally seems like TBI motors last as long as you really want them to... many go over 200k! With the ones I've driven they may last that long, but power and milage suffer. Most are getting pretty worn by 150 or 160k. If you wanted to swap motors, but not rebuild yourself keep in mind that rebuilt long blocks (stock) can be had for about 800 to 900. Bolt on the intake, TBI, and good to go another 150-200k! OH YEAH... by the way... the oil pressure guage jumping up and down is a common occurance on those trucks. Generally installing a new op switch fixes the problem. GM has a Technical service bullitin on it and a new op switch part #. Any parts guy should be able to help you out.

1987 Chevy K5 Blazer- 350 TBI

 

[MICHIGAN BLAZER]

Wow......you guys really need to read your posts a little more slowly. I couldn't understand why everybody was telling 90 that 1/4 quart per oil change isn't that bad when he was really burning a quart a week!! and asking for his mileage when he stated it two posts up.....not trying to make anyone mad.......just didn't like reading through all of the gobbledy gook that really didn't pertain to his problem.....I'm sure it was frustrating for him as well.

<font color=red>MICHIGAN BLAZER
<font color=green>89 Fullsize Blazer
87 Cherokee
65 IH Scout

 

[**DONOTDELETE**]

The other question is how many mile do you drive in a week?
I'm going to replace my 305 soon,it uses 1 quart every 100 miles or so!LOL

 

[1990SilveradoK5]

Yes, it is alittle frustrating, but if it helps in the end it is worth it.
125K on the motor, I drive 250-300 miles a week, getting 12 MPG.
Still no puddles, I drive mostly in the morning in the dark and the evening in the dark so trying to watch for excessive smoke is somewhat challenging.

But if I follow you all correctly, if it is pushing it past the rings I should see large quantities of smoke when accelerating, which I don't.
I have not had time to look at it since yesterday when I posted the question so be patient with me, hopefully Thurday evening I will get it in the garage for some diagnostic work. (compression test, etc.)

Gone Large and Loving It.
Keith

 

[**DONOTDELETE**]

Have you checked the rear seal? Thats where most of my oil is going.It stays wet around the reaof the oil pan and starter.It hardly drips at all.Just something else to consider,good luck.