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2005 chevy trailblazer_lt_ext
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I am at a loss had shop repair our A/C on 2005 TB V8 ext LT 143k miles.Background... During repair they broke the line from condensor to evap core. So they had to take entire dash apart to replace core. after replacing none of the actuators worked, after they took apart 3 times replaced all acuators and HVAC control unit and heater core and A/C compressor and all lines, finally fixed. Get it back after almost 2 months worked ok for a couple hours. They all of the sudden i get low oil pressure and guage drops to 0. said turn vehicle off. dont drive and get ready to bring ini start car warms up then exhaust starts blowing white smoke, and engine starts knocking bad very loud. so it sits for a couple days they come and tow since now battery is dead. they jump and start to check it and its not blowing smoke anymore and not knocking. now it just has a MIL light and a misfire. Shop has not been able to determine issue some days it knocks some days it has misfires. They said they think its a failing oil pump.

I spoke with another shop who told me there is no way, in 40 years of working on GM vehicles he has never seen a oil pump fail on anything.

Anyone have any ideas what might be going on? Could their work on the truck taking dash apart or doing anything have caused this?
 

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The white smoke you describe is usually coolant and can have a very sharp smell.
  • Oil going through the combustion process is sweet smelling.
  • Oil that gets past the exhaust valve seals will make your eyes water and burn your nose.
  • Gasoline is usually gray or black and you'll recognize it pretty quick.
  • Too lean - after a good run, will be light grayish-white and will curl paint and just stinks! \
  • If your cat is on fire (they do) it will smell like what we call "burnt cotton candy".
So - going on your post, white smoke is never a good thing.

I am not understanding it being there, then not - that's a little odd - but I have suspicions to which I am not going at the moment.

HOWEVER -----> Getting coolant to come out the tailpipe is NEVER good news.

Sounds to me that you might have a failure of a head gasket, or a cracked head....... this is usually caused by serious overheating. It could just be a coincidence - and I don't believe in coincidences.

Any shop having the dash apart multiple times to repair something they accidentally destroyed and them working in the same area multiple times to correct their mistakes and taking out the heater core - this very well could be their problem.

Perhaps when they dumped the coolant to work on the AC-side they didn't refill the cooling system correctly. I've seen it happen.

In any case - the white smoke isn't likely to go away - and the knocking-missing is telling you that you may have serious internal problems.

OK - that said - let's investigate the lost oil pressure. I am pretty sure that GM is using the projected oil pressure values theory for normal operating conditions.
  • That means that the oil pressure gauge on the dash - has values that are sent from the ECM to placate the driver and do NOT reflect the real oil pressure.
IF you get that warning light - it means that you are below 12-14lbs of oil pressure.
  • There IS a switch - it's not a sending unit that tells pressure - it only opens that switch when the oil pressure truly is under that value.
IF the pressure drops below that value - you get the light and warning and reduced power.

Any engine running a low enough pressure of
  • ---> let's assign an arbitrary pressure here..........
  • ---> say........ 15lbs at idle.......... will be noisy while it's damaging bearings, bearing surfaces, valve action from lifter pump-down, etc.
Lessee here ----> any shop that cannot run a mechanical oil pressure test - well --- it isn't a shop. Does this place sell tires or floor mats? It doesn't sound like a real shop.

And YES there are times oil pumps fail - but maybe not like you think. It's the pickup screens that can sometimes get clogged up - the 4.2 I6 is notorious for this.
  • Many small block Fords had the same trouble - and I blame most of the clogging from oils from Pennsylvania. Now - I know oils have changed a lot recently - but I still dislike any paraffin base oils.
Cheap oils, oils that cannot take the heat and they liberate their hydrocarbons and the leftover product turns into sludge - is not an oil I would want in my engines.

I've taken so many engines apart - and each time I could SEE what oil the owner was using.
 

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2005 chevy trailblazer_lt_ext
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Discussion Starter #3
I thought Head gasket to at first, I checked oil it was good there wasn't any bubbles in it or coolant reservoir. Also the oil wasn't milky at all. Also if it was head gasket i wouldn't expect it to just stop blowing the smoke and stop knocking. The oil pressure was checked and while gauge was showing nothing it had good pressure. i replaced the sending unit and still it would drop and show nothing. I also know the pickup tube for the oil pan is part of the pan. Our pan was changed about a year and half ago since it was cracked in a car accident. they also changed the differential at the same time since it cracked as well.(Vehicle should have been totaled but State Farm didnt and put more money than it was worth into it) The whole front end has been pretty much replaced as well as tons of other parts. Now when I am getting ready to sell i have this issue so again i am stuck with it. Its got well over 3-4k in new parts in it. so with that the only conclusion i can come up with is they messed up when they changed the heater core and over heated it and slightly cracked head gasket so its not a every-time issue? I am guessing that is probably why they are dodging me and not giving me a straight answer after they have had it for two months now.

It was a merlins shop in Illinois, now its a Mike More Miles since they where bought out. I used to use them for things I couldn't do, IE the original A/C issue.

Thank you
 

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They may have tried to cover the damage with Aluma-Seal or something.

I'd hold their feet over the fire to make you good on the repair, no matter what it costs them. They screwed up somehow.... and I would NOT OPT TO TAKE IT TO A DIFFERENT SHOP.

Once it leaves them, they wash their hands.

What state are you in? Does your state have a mad-dog auto consumer's agency?

Do you need a killer New York or Los Angeles attorney? They live for this sortta lawsuit.
 

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Discussion Starter #5
we are in Illinois, i dont know what next step is.how could i tell if they used something?
Is there something i can check if they say its something they didnt do? Or am i just going to have to walk away from it?
 

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You drove it in.. you had a repair and while in their care, they screwed it up.

They HAVE TO MAKE IT GOOD. DO NOT TAKE THE VEHICLE OUT OF THEIR SHOP.

Call an attorney, get him on a percentage of the action (with a performance bond or commission, or whatever your state has) . ..... and make him write a letter first.

Letters from attorneys usually get results.
 
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