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2003 chevy trailblazer_ltz
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5 Posts
Discussion Starter · #1 · (Edited)
Problem suddenly with timing, valves or head *WITH VIDEO*

Hi everyone, suddenly have a problem today with the trailblazer

some history .. have the car already almost a year and a half .
Its got 124,000KM original.
It's a chevy trailblazer 2003 with a 4.2L inline 6 Vortec block. since more than a half years i'm driving (2500 kmters) on LPG (gas €58 cents a liter, petrol 1,77 Euro) with a prince vsi2 system with separate valve lubrication per cylinder injection system on the timing of the engine JLM. (please note that almost all the USA cars with big engines are rebuild to drive LPG here)
Oil always neatly replaced on time (mobile 1 5w30) with filter also naturally. Oil change interval is upcoming according to board computer but nothing over time. drove it today and suddenly I heard a sound. can explain this better by using this video: (ps, it is idling just ok, but noticed the problem also because I had 30% less power.)

https://drive.google.com/file/d/0B0YybGynCtx-dFJVX0ZMaHc1bjQ/view?usp=sharing

No warning or similar engine lights that came up. Oil pressure OK, temp OK, I'm thinking the following:

- or chain tensioner distribution is loose
- valves bent (by the above)
- head off. Obviously hope the 1st option,, but well holding my breath.
Tomorrow will just pull out the plugs and see if there is one which is white / lean because of gas .

what do you think? All feedback is welcome. Thank you in advance! And Merry days. gr Rootje from Amsterdam
 

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2003 gmc envoy_sle
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15 Posts
Sorry to say that but one or more of your bearing is ****ed! Had the same noise last year with my Envoy. One rod bearing was completly down and the others begin to be ****ed too. Replaced the engine with a used one. Sorry about that bro! :(
 

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2003 chevy trailblazer_ltz
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5 Posts
Discussion Starter · #3 ·
well,,took oil carter out today but no metal grindings,,no metal pieces whatsoever...

changed oil rightaway..

i changed the oil of the gearbox bout 2 months ago and could not find any metal in there at the magnet .

really weird problem...
gonna take off the starter engine and valve cover now to see if i can find anything.

when the engine runs idle,,no shaking of anykind indicating bend valves...
 

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2003 chevy trailblazer_ltz
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5 Posts
Discussion Starter · #4 ·
reading up on the problem,,more and more i get the idea that its the water pump and connected to that the fan clutch.
I can see the fan move forwards and backwards a little bit when its spinning.
 

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2003 chevy trailblazer_ltz
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5 Posts
Discussion Starter · #6 · (Edited)
Ok,,thought i'd update this situation.

While the knocking sound was coming from the top part where the chain goes through, we decided first to take the valve cover off and have a look..

not much to be found at the chain except some slack but this is automatically corrected by the tensioner.

So we feared the worst and dropped the oil carter after first having to remove sooo much before we could reach the rod bearings..
And indeed...the problem was with the first rod bearings..
since both halfs of the bearing have a sort of protection clip to prevent them from sliding over each other,,these were gone and they have slipped over each other :cry:..
We removed all six and got parts from the USA ,new bearings since we have the carter open now anyways, give it a try to replace the bearings and hope for the best. *and was thinking back how this problem could have happened..but seeing the design of the oil distribution,,it got clear to me. When offroad about 2 months ago,,and we were trying to get upto a **** which was a bit steep..but sliding away could times not able to get on it..after 3 attempts we got on it,,but remember 1 time we were sliding back and the oil light came on but also disappeared quickly.. i think then the damage got done on the first rod bearing..

All the other 5 bearings were fine btw.
We had a look at the crankshaft and did see some minimal scratching on the first part were the issue occurred with the failing rod bearing.
Now we got new seals and cleaned out the carter, put everything back together and did a oil flush (because cutting open the oil filter and looking inside the carter we did see a lot of copper color metal grindings in the old oil. After the flush, new filter and new oil.

What i did notice,,is that the original bearings did not have a oil hole in the middle of it.. And the ones i ordered from Big Red autoparts on ebay 800690-RKP-2539-RB3190 Engine Connecting Rod Bearing Set DNJ RB3190
did have holes in them...:undecided while these are the correct bearings for a 2003 4.2 ltz

so,,we started the car and it ran on 5 cilinders,,after some troubleshooting and excluding turned out to be one of the coils. Replaced that,,then it ran fine.
Hardly drove with it because im gonna trade it in next week for a new 2015 gmc sierra 1500 denali,,but of course hoped the rod knock would not come back and that the scratches on the first part of the crankshaft would not have a too bad effect.
But driving it home i already heard a very faint rattle coming from the engine which sounded painfully recognisable. When i got home very gently in neutral gave it some rpms,,and heard that rattle again.

Now my question is,,how many of you have experience in replacing rod bearings and have successfully got away with it.. Of course the big question is ,,is your crankshaft still in alignment because a micro millimeter would cause troubles i think...
I have read something on this forum regarding a plastigauge measurement? on the crankshaft or something to determine if ur crankshaft is still ok?

Any feedback on this would be very much appreciated,,because otherwise i can kiss my 8000 Euros trade in goodbye and im gonna need to sell it in parts i guess..

thnx for taking the time to read this..

Rob
 
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