My Oil Nightmare

[scott100]

Oil nightmare

This dilemma took me a week to figure out. Let’s see if anyone here can guess what the problem was??
I own a 1998 Chevy Tahoe that had 52,000 mile when the nightmare started. One morning in May 2005 I started the Tahoe and my heart stopped, the lifters were tapping to beat the band. I immediately turned the key off and sat there in shock. Well I thought to my self I haven’t started it in over a week maybe it just needed to build up pressure. So I started it again and the same thing, I checked the oil pressure and it was ok at 60#. I let it run for about 10 min. and they were still going at it (like an old 350 with 150,000 miles that is 3 qts low on oil). Well my next step was to check the oil, and I could not believe it, the oil was at the full mark BUT IT WAS BURNT! And burnt bad! It was very sticky and had that burnt oil smell. What caused this?
The last oil change was 1500 miles and apxox 8 weeks before the incident happened. I was using Castrol Syntec 5W40/ K&N filters with oil change intervals of 5000 miles. The engine was never over heated, not driven hard and was not pull/hauling anything on last oil change

 

[ToyotaNSaturn]

PCV system completely clogged? What kind of oil was used the previous 50K miles? Coolant leak? Cracked head?

 

[Dagwood]

OK...I'll bite.
Bad head gasket?

 

[Drew99GT]

Intake gasket failure?

 

[scott100]

Always CS, no cracked head, no coolant leak, PVC system not clogged and not a bad head gasket..

 

[Pablo]

Are we talking sludge?

 

[JohnBrowning]

Are you leaking air into the system at the pickup tube o-ring? A little bit of air in the system even with ok oil pressure will cause all kinds of heck with your lifters.

The black sticky oil in that short time frame has me at a loss. If I had to venture a guess I would go with a malfunctioning EGR or coolant leak!

 

[scott100]

Nope not the intake gasket.

 

[scott100]

John you got it, it was a bad EGR valve, the thing thats I still don't get is that it was not pluged or full of carbon. It still worked but would not close all the way. Thats why I never got a "check engine light"

 

[Steve S]

how did the engine run? J.B. is the master.

 

[Drew99GT]

Wouldn't it be worse having the EGR stuck closed?

JB

 

[427Z06]

Nice call JB. That would of been the last thing I would of suspected.

 

[scott100]

It ran just fine and yes I beleive it would be worse if it stuck closed, but then I would have gotten a check engine light

 

[SWS]

Tell us the rest of the story. When you fixed the EGR and changed the oil did everything work out OK?

 

[kc8adu]

i fail to see the connection between the egr valve and cooked? oil.
i can see where a plugged pcv system would be a problem but egr?
and my first suspect would have been the defective o rings on the pickup tubes some of these were born with.

 

[mechtech]

Good call, JB.
It's the last thing I would have guessed - I can't see the connection.

 

[ekpolk]

This is one of the reasons why I always pull my dipstick and "eyeball" my engine room once or twice a week, every week, even with our family's two relatively new vehicles (2001 and 2004 models). I'm not trying to sound like I'm scolding (really), but I strongly recommend doing this. I too almost learned this the very hard way after an oil change that resulted in undetected damaged drain threads. Had I not been looking, I'd never have noticed my oil steadily bleeding away until it was too late.

 

[Vortec_4300]

quote:

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Originally posted by ekpolk:
This is one of the reasons why I always pull my dipstick and "eyeball" my engine room once or twice a week, every week, even with our family's two relatively new vehicles (2001 and 2004 models). I'm not trying to sound like I'm scolding (really), but I strongly recommend doing this. I too almost learned this the very hard way after an oil change that resulted in undetected damaged drain threads. Had I not been looking, I'd never have noticed my oil steadily bleeding away until it was too late.

---

Roger that, ekpolk.

Truth-be-told, this is something that people did with much greater regularity "back in the day" when oil was consumed at a fairly high rate in older automobiles, and most guys realized that a check of the dipstick was a weekly minimum event.

I have a 2005 Chevy Silverado that just turned 14K miles, and I check the dipstick weekly.

 

[Pablo]

Excellent JB - no need to whittle 'em down. Just nail it and move on

Oil can and will be rapidly "cooked" (oxidized) and "nitrate polluted" (NOx) by excess exhaust gases. IMHO it's one of the hardest things on motor oil and will turn it to the worst form of sludge. Indee a good argument for yanking your stick at least once a day!

and sorry to say a good argument for using an oil that can withstand such abuse (to some extent)

 

[TallPaul]

When I worked for a city parks department we were required to check the oil every morning.