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Discussion Starter · #1 ·
09/01 TB I6 w/182,000 miles.

I was in the garage when my wife came home and I noticed a burning oil smell. Opened the hood and saw that the valve cover gasket is leaking.

Here is what I'm looking for assistance on:

When I pulled the dipstick, there was a lot of pressure behind it. psssssssssst. So, I have crankcase pressure. It's instant pressure. I can start engine for about 10 seconds turn it off then open oil cap or pull dipstick and psssssssst.

I pulled the baffle off and there is oil in it. I know I have to change the valve cover gasket, but what should I be looking for regarding the cause of the pressure. Thankfully (I hope), I DO NOT have any blue smoke from the exhaust.

I'm thinking the vent hose from the manifold may be clogged? Should I blow it with air? Should I use an engine flush? Ideas?

Thanks,

STISS
 

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I don't remember ever seeing this issue in my four years here. The I6 doesn't have a traditional PCV valve, which is why the throttle body gets so filthy and needs regular cleaning. So there is only a simple hose for crankcase ventilation, and I'd blow it out with air. It's item #6 in the exploded diagram. Any chance of old oil causing a sludge build-up? What's your oil change history been like?

 

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Discussion Starter · #3 · (Edited)
Used Amsoil for most of life. Last couple years (after moving) used regular oil with 3k changes. I have notice more 'gunk' on oil cap since changing to regular oil. :worried:

That tube (crankcase vent hose) is what I'm thinking of too. I'm gonna pull it this afternoon.

PS. Thanks for reply. I've been searching all day about this, and haven't seen anything. Yay! I'm first.:cry:
 

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Discussion Starter · #4 ·
Update:

Okay pulled the hose. Started the engine. NOTHING came out, no pressure from it at all. Blew in with an airhose and voila! It started blowing! :thumbsup: Must have been clogged with gunk. Put hose back on, turned off motor, pulled dipstick, just a little pressure now. psst.

Any recommended engine flushes? Or any other recommendations for cleaning the engine?
 

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Used Amsoil for most of life. Last couple years (after moving) used regular oil with 3k changes. I have notice more 'gunk' on oil cap since changing to regular oil. :worried:
If I recall correctly... once you switch to synthetic, you are not supposed to switch back. It could be causing your oil to coagulate. I'd try to flush out all the regular oil with synthetic... then change your oil again in 500 miles or so.
 

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not to hijack the thread but I have an 05 with 104,000 and can smell oil when the engine is under load (take off when towing, hard acceleration, etc) could this be similiar issue with the vent hose....the oil doesnt smell burnt if that helps
 

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Discussion Starter · #7 ·
not to hijack the thread but I have an 05 with 104,000 and can smell oil when the engine is under load (take off when towing, hard acceleration, etc) could this be similiar issue with the vent hose....the oil doesnt smell burnt if that helps
I noticed the smell because of the oil leaking on the manifold. I only noticed the pressure because I pulled the dipstick to see how much oil was leaking, and that's when I noticed the pressure, and the pressure most likely blew the gasket.

Turn your engine off and pull the dipstick. If there is a lot of pressure, you may have a similar situation. Otherwise, I'd listen for other replies to your question.

Back to my question about cleaning. Should I use an engine flush, or just go back to the synthetic like James said? I want to get the gunk out.
 

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If I recall correctly... once you switch to synthetic, you are not supposed to switch back.
That's an old belief that isn't true today. It actually had to do with sythetic having a different effect on gaskets and seals than conventional oil. Switching back could cause leaks because the seals had swollen to a tighter state with synthetic in the engine. There is not problem with switching back from synthetic to conventional oil today.

That said, it could still help to go back to synthetic, as it's less likely to support sludge buildup.
 

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2007 chevy trailblazer_ls
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:iagree: You can switch back to convential motor after running synthetic with no issues. The motor has 182,000 miles on it and depending on what kind of driving was done (short trips with out letting the engine fully heat up and blowing the junk out) constantly can cause build up. I think you can go either route-engine flush will be faster and do a better job or go to synthetic and it will just take longer and not clean out as much. :m2:
 

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My oil pressure gauge has been maxed out since I bought it. I never really paid any attention because I never saw any problems with smell or such. Does the V8 have a similar setup - just the hose to ventilate the crankcase?
 

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The V8 has a normal PCV valve. But that can't POSSIBLY have anything to do with high oil pressure. Doesn't a maxed-out gauge worry you for other reasons, like blowing out seals? Since the V8 has an analog sensor, instead of the I6's on/off switch, just change it. Or did you already and it didn't work?

PCV valve - item #900:

 

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So if I were to go with syn and want to just switch back due to conveniance there should be no problems? I have the amsoil oil and filter ready and waiting in my garage as soon as my change engine oil light comes on. Just dont want to cause potential issues later on. OD 85,435mi no leaks what so ever.
 

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So if I were to go with syn and want to just switch back due to conveniance there should be no problems? I have the amsoil oil and filter ready and waiting in my garage as soon as my change engine oil light comes on. Just dont want to cause potential issues later on. OD 85,435mi no leaks what so ever.
Like others have mentioned - no problem. I have another vehicle that has over 200K miles on it. I have changed back and forth and mixed dino and synthetic oil over the years. No problems whatsoever!
 

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Sorry, slightly off topic, but I should respond to Roadie's post. When I bought the vehicle from the dealer and noticed the oil pressure gauge was maxed out, I thought "That can't be right". I turned the key on (without starting), and it jumps to max as soon as the electricity is on. I didn't see any evidence of high oil pressure, and since the pressure can't possibly be maxed without the engine running I figured I would ignore the gauge. I never have given it another thought, until I read the thread.

I was too cheap to think about replacing it. I didn't mean to downplay the pressure problem, I just never thought I had one. I still don't think I do. I think the gauge is shot.
 

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Ahhhh, thanks. Cheap fix if it's just the gauge. $5 stepper motor from Ebay. Confirm it with a scan tool (or scangauge) that can read the serial data stream, to make sure the PCM is getting accurate pressure data.
 

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Thanks for the advice. I'll give that a go. Sorry, I am a recovering GM dealeraholic. (you know, charge you up) I could tell you my story but I'll leave that out for now. I actually had really great service there for a while and then the service manager changed.

So now I tend to leave things I think can wait. My Venture van doesn't have a working gas gauge, but I'm saving those dollars.:m2::woohoo:
 
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