Weird valve train noise problem - a riddle

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Truck: 1997 4x4 K1500 heavy chassis with 5.7L Vortec V8, 75000 miles
I bought this truck new and for years told everyone how they should've bought a Chevy ...perfect all the time. In the last year however, I've had
to replace the alternator, serpentine belt, idler pulley, intake manifold gasket, fix the hose fitting (crusty) on top of the manifold, egr valve, replace front discs, calipers and pads etc. Whew!
Then, since the idle was ever-so-very-slightly rougher than when new, I ran a bottle of Lucas brand fuel injector cleaner through it (full tank). About 1/4 of the way into the tank following that, I started getting very loud lifter knock (scary loud) on the passenger side of the motor. Oil level was fine and looked OK. Always have used Mobil 1 Synthetic, 5-30W as spec'd, changed at 3k mile intervals. This oil was about 500 miles from a change. The lifter noise would quiet down after running for awhile, or driving very slowly with a very light pedal. Note that the coolant level was low and I had not filled it since I was out of Dexcool, but the temp gauge said the usual 185 F or so just like always.
Over the next week, it got worse to the point where you could hear loud noise from the entire valve train under the valve covers on both sides of the motor. So far, my mechanic (non-dealer) and the dealer had no clue and neither did I. I was so busy listening to the noise (and worrying to death about thousands of dollars in taking motors apart becoming necessary etc) that I never did think to check oil pressure so I have no data on that, even now.
On a whim, I changed the oil with my usual Mobil 1 and put a new filter like always (Purolator Pure One), filled the reservoir with Dexcool. The motor still knocked and made noise. When shutting down, a bunch of the coolant chugged into the motor so I refilled it. Again, a bunch of it went into the motor. Topped off with water and it's been stable and quiet (no gurgling noises) since.
The next morning, the motor started up and sounded brand new ...absolutely no noise. Even the very light tick-tick-tick from the lifter that had always made that noise right from the factory had gone away and the motor even runs smoother than ever, even at idle. Like magic....
It's been fine since then and it's been about a week now. Once, it did knock a little upon start-up and I noticed the oil pressure was at 20psi on the gauge and the knock immediately quit as the pressure came up. My normal oil pressure is one mark above the 40 psi when cold, and right at 40 psi when driving. Now, the oil pressure is averaging one click above the 40 psi mark when driving, and can be as high as 50-60 psi on start up ...higher than it used to be, even with new oil.
My mechanic now guesses that I had a sticky oil pressure relief valve that was recently sticking open. He recommends flushing out the motor (oil) to clean out deposits and what not.
Sorry for the loong story, but I'm puzzled ...does the above sequence of events make sense to anyone? Comments on what is or was wrong? Does it make sense to flush out the oil to clean things out? Why did new oil and topping off the coolant fix it???
Thanks a mil!
Brian Albany, OR
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Sure it was a lifter. A leaking exhaust gasket can make a ticking noise too. Double check this. I have seen this twice now
Matthias

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The light ticking noise is gone now, otherwise I'd agree that a minor exhaust gasket leak could sound like that. I've seen that (and heard it) before. The valve train noise was gawdawful and on both sides of the motor ...no doubt there. My concern now is that the new oil/filter is hiding something else ...I'm hoping for insight from someone on what may be wrong.
Thanks, Brian
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I was thinking the same thing ..felt like a damn fool for noticing the coolant low and then waiting to fill it. I wanted to pour Dexcool into it and didn't have any. Probably a bad thing, and probably resulted in overheating the heads. The temp sensor is probably down on the water jacket somewhere and not sensing the high temps on the heads.
That said, note that I know the difference between spark knock, exhaust leaks, lifter noise, and noise coming from rocker arm assemblies. This started as lifter noise on one side of the motor ...the lifter being down in the block and the temp gauge reading fine, I doubt that this had anything to do with the head temperature unless a rocker arm was trying to cease up. Later, it progressed to noise from across both rocker arm assemblies on both sides of the motor ...temp gauge still fine. Heat radiation from the motor did *not* seem abnormal, not even hot. I've rebuilt several motors in my life and know very well what a hot engine is like, e.g. during the first 30 minutes of starting a brand new motor. Back when I drove junk because I was broke, I had motors overheat for various reasons. The motor in this truck appeared to be at normal operating temperature all along.
Why has the oil pressure been as low as 20 psi and as high as 60 psi? It knocked when the pressure was low and as soon as it comes up to normal pressures, it runs silent. I understand why it knocked when low ...lifters were probably drained down a bit and not pumping up. The real question has to do with why would it run low and what to do about it?
As far as the coolant disappearing, note that it has always been fine except when the intake manifold blew leaks out on all sides basically overnight (a vortec specialty from what I hear). I have no idea why it was low and there is no sign of a leak anywhere and no water pump noise or bad water pump bearing noises or anything like that ...it was just low. My mechanic said that once it starts to get low, then the motor can run hot and you lose a lot to steam because the steam disappears out through the overflow tube on the reservoir. Maybe, but no clue on where the coolant went... Hmmmm. Hope I don't have a leaking head gasket. That should show up as rough idle eventually. Had that happen on a P.O.S. Pinto once back when I was in college.
Life goes on. I'm still leaning towards a combination of oil pressure relief valve sticking and releasing oil pressure to the crankcase plus maybe some hotter than usual head temperatures as the reasons for the recent issues. Nobody mentioned that the GM-provided AC oil filters have anti-drainback check valves in them, but the Purolator filters I've been using do *not*. That could be a part of the problem too. I'm sticking with AC from the dealer from here on out. And I'll be damn sure the coolant stays full like I should have in the first place ...none of the cars or trucks I've driven previous to this one (I'm 44) were ever that sensitive to slightly low coolant. I might run some 5-minute flush through the oil and give it another change and I might (after that) run Rislone in it for a couple of weeks plus another change. You'd think that since I've always done 3k oil changes and have always used Mobil 1 Synthetic, which is high detergent, that I would *not* have any build up issues in the motor ...hmmmm. Call it neglect if you want, but I've always babied this truck and it's always been very well maintained except for this once and only time where I drove for a while slightly low on coolant. No vehicle that I've owned previously got the high attention that this one has.
Brian
.

[snip]
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Brian D wrote:

I've read a lot of reports that say M1 5w30 is a lot thinner than it's rated...
I'm not sure about the vortec motors, but the LS1 based engines are built rather loose, and nobody on the LS1 boards recommend this oil in them.
I ran M1 5w30 for about 95 out of the 98K miles I put in my old 4.3 Blazer. The motor turned into a complete turd on me by 80K or so. Wouldn't hold 65-70 on the slightest hill on the highway, got 12mpg, burned a lot of oil. Right around 98K, the motor developed a NASTY cold knock that sounded like someone tapping the block with a hammer.
Ever since then, I've hated synthetic oil. I'm sure the simple fact that I ran synthetic didn't do things to the motor, but the claims about M1 5w30 running thin, WOULD make sense...
-marc
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That's enough for me. No more Mobil 1 in my truck. Back to Castrol, probably 10-30W. And I'm using the anti-drainback checkvalve AC oil filters from the dealer from here on out. NOTE: Dumping STP in the case would quiet the knocking for a day or three, so hmmmm... thin oil? Filter that doesn't prevent drain back? Clues...
It's been 2 weeks on this oil change (still M1 5-30) and the motor is still quiet. Knocked a time or two when cold the first week and since then, but been silent otherwise, and the short number of times that I did detect a knock it's obvious that the trend is towards quieter. Seems to be going away. But I'm still going to flush the oil system and replace it with Castrol and the filter from the dealer...
Brian
--
http://www.advantagecomposites.com/tongass -- My 22' Tolman Skiff project


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"Marc Westerlind" < snipped-for-privacy@emc.com> wrote in message
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You don't need to get the AC Delco from your dealer.... unless that is the only place you can...
~KJ/TLGM

question
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question
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Glad I opened this discussion with you guys. I'm getting lots of hints and ideas on what might be wrong. I suspect that my problem is alive and well but temporarily hidden by the oil change and coolant fill. I'm going to watch the coolant level and see if it is still going down with no visible sign of a leak. Assuming it drops, I will take a morning cold sample of oil from the oil pan into a clear jar to see if coolant has settled to the bottom of the oil. Either way, towards the end of the 3k miles this oil will get, or as soon as noise develops again, I'll try to get an oil analysis done to find out what's changing. I'm starting to suspect a hidden coolant leak into the oil, probably into the lifter valley as others have pointed out. We'll see ...it'll be babysat more carefully than a newborn for awhile here...
Brian
PS: And I'm going to change out my Dexcool, block and radiator drain, as others have said ...I'm 7 years into what's in it now (factory fill). And I am going to switch to Castrol ...what I used for many many years prior to changing to Mobil 1 in this truck. Even a rumor of the stuff running thinner than it should is enough to worry me away from the stuff. Castrol has a longer stronger history and I'm not so sure having natural organics in it is so bad ...old engines use less oil because of the coating that varnishes the inside of the motor and still last. The one fellow that used Mobil 1 until *he* had a bad lifter noise problem at 80k (I'm at 76k) and started using lots of oil sounds spookingly familiar...
--
http://www.advantagecomposites.com/tongass -- My 22' Tolman Skiff project


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""Doc"" < snipped-for-privacy@nope.com> wrote in message
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Do ya suppose that the coolant is leaking into the lifter valley via the -known- problems with leaking intake manifolds and contaminating the engine oil?
I'd sure suppose that.
Fix the leaking intake manifold gaskets, you dodged the bullet this far but you're not likely to get another shot.
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My intake manifold gasket was replaced last fall. It started to leak a little, then after about a week it started leaking big time ...like rain. I can't see how a leaky intake manifold could get coolant into the oil unless it's leaking across the surface of the head itself ...correct me if wrong, but isn't that the only common point? Anything else leaks outside the motor on the top or sides, right? Hopefully this possibility was ruled out last year ...the guy that did the work is someone I've used for nearly 25 years and has been top notch and very reliable, and smart etcetera. I suppose anyone can make mistakes, but so far, he could not have been a better mechanic. After all, he put up with the F.O.R.D.s that I owned previously...
Brian
--
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"Neil Nelson" < snipped-for-privacy@sbcglobal.net> wrote in message
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Brian D wrote:

I'm correcting you, because you are wrong. It's very common on these engines for coolant to leak both internally and externally. When dexcool mixes with oil very slowly, it creates a nasty brown sludge that coats everything. This does strange and nasty things to lifters.
Ian
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Well, directly below the coolant passage between the intake and the head is the lifter valley, so you tell me...

I've replaced dozens of leaking intake gaskets on GM 90 degree V engines that had a nice identifiable external leak -and- a nice wad of sludge/gunk piled up right under the coolant passage.

At this point, the only sure fire certainty would be an oil analysis.

It wouldn't necessarily be -his- fault given the inherent bad gasket design/material in question here.
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Oil analysis? Second time I've heard of it lately ...a guy with an outboard on a boat was talking about it and how they found fuel in the oil. Where do you get an oil analysis done? Mail a sample to someone or is this the kind of thing you can find locally?
Brian
PS: Yes, I'll do some checking around locally ..but in a small town, I wonder about the quality of the analysis...
--
http://www.advantagecomposites.com/tongass -- My 22' Tolman Skiff project


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"Neil Nelson" < snipped-for-privacy@sbcglobal.net> wrote in message
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wrote:

a
suppose
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To check the oil for water or coolant, pull the dipstick and drip one or two drops on the hot exhaust manifolds. If it just smokes there is no water or coolants but if it spatters there is some water or coolant in the oil.
Just give it a try
Good luck Matthias
wrote:

leak
the
better
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Thanks. Assuming the coolant level drops again, I will be checking for coolant in the oil in several ways now:
- Brown foam on top end of oil line on the dip stick and possibly on the oil fill lid - A sample of cold (morning) oil from the pan into a clear glass jar (water settles underneath the oil) - Smoke or sizzle on the exhaust manifold check (see below) - Send in an oil sample with a Wal-Mart or K-Mart kit as doc described (I live in a small town ...not the best for fancy analysis systems)
Between all of these, there should be no doubt whether I have coolant in the oil or not. Since my coolant mysteriously disappeared ...this has got me wondering. I'll be watching the coolant level careful until it drops, and will be listening carefully for any hints of increasing lifter or valve train noise like I had before.
Thanks, Brian
--
http://www.advantagecomposites.com/tongass -- My 22' Tolman Skiff project


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"mathijs derks" < snipped-for-privacy@sasktel.net> wrote in message
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Thanks.
--
http://www.advantagecomposites.com/tongass -- My 22' Tolman Skiff project

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""Doc"" < snipped-for-privacy@nope.com> wrote in message
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On Sat, 19 Jun 2004 16:02:09 GMT, "Brian D"

http://www.blackstone-labs.com/free_test_kit.html
and I hope they were talking about a 4 stroke outboard...
-Bret
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