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Discussion Starter · #1 ·
This season, my 2006 Z06 has had trouble starting when it is up to temperature (and it gets worse when it is hot outside).
When the car is cold, it starts up no problem, but when I'm doing multiple starts/stops (errands, etc), it can actually get to the point where it won't start.
Has anyone come across this?_ If so, please share how you solved it.
One thing I have heard is that it could be the starter motor, somehow getting worn or increasing friction when it is warm.

It's not the battery, not the alternator._
I have had both tested, and they are in perfect shape.__
When I thought it might have been one of those issues, I was putting a trickle charger on between using it. However, it wasn't the extra charge it needed, it just needed to cool down.
When I had the battery and alternator tested after the car wouldn't start, I left it for an hour, and it started (with a little hesitation since it was still a bit warm).

​​​​​​​Any thoughts/tips would be appreciated.
 

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You need to expand on not starting as answers will be different

Is engine cranking over ?, if not then could be starter solenoid

If cranking then it can be anything as the MAF is dirty or bad, or the wiring pins have bad crimps to the wires of MAF
leaking gasket for MAF, unmetered airflow, loose or cracks of airbridge and it's couplers from aircleaner to throttlebody
Weak O2 sensors to dirty sparkplugs to lower fuel pressure once warmed up
Hotter engine bay is, leaner fuel trims will be

Check for any error codes, any auto parts store should have a code reader to borrow or best is a OBD-II scanner to see if running
way too lean, and conditions of all above
 

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Discussion Starter · #3 ·
Thanks for the insight/feedback.

The engine cranks over, and when it cranks fast enough it starts.
As the engine gets warmer/hotter, the cranking slows down.

I have read on another forum that this could be caused by a heat soaked starter / solenoid.
It sounds like the solution is either to wrap it (block from heat) and/or fix/replace the starter / solenoid.
 

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If having long tube headers good chance the right one is too close to starter adding more heat to it and
requires using a thermal wrap to protect starter

In any case pull starter and have a auto parts store to test, repair if need be or replace.
Most likely the starter solenoid which they should have a rebuild kit

Good chance the right exhaust manifold moved out of way to have room to take starter off and back on.
 

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If having long tube headers good chance the right one is too close to starter adding more heat to it and
requires using a thermal wrap to protect starter

In any case pull starter and have a auto parts store to test, repair if need be or replace.
Most likely the starter solenoid which they should have a rebuild kit

Good chance the right exhaust manifold moved out of way to have room to take starter off and back on.
Hi, This is Arno. I have a 2008 Z06, with the exact same problem: not starting when hot. At the second or third stop (running errands or driving), engine cranking, but super slow, just like draining the battery until everything dies. When cold, next day, all starts like nothing happened. Car has been at 2 dealers over the past 4 years: all together, stayed at least 12 months for repair, but nothing worked so far, and the second dealer gave up and asked me to take the car back.
FYI, I have the car for 7 years, and originally it was not doing that, but since GM changed the engine due to valve failure (!!), nothing but problems.

Have been changed to new (per GM dealer): battery, starter, alternator, cable line from battery to engine. I got the right exhaust pipe wrapped with insulation fiber and added an insulation plate to protect the starter from heat.... but nothing worked so far !!

Any help ?
Any address of Z06 mechanics in LA / SF that could have experienced and resolved this issue.
Thanks a lot
 

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Discussion Starter · #6 ·
Hi, This is Arno. I have a 2008 Z06, with the exact same problem: not starting when hot. At the second or third stop (running errands or driving), engine cranking, but super slow, just like draining the battery until everything dies. When cold, next day, all starts like nothing happened. Car has been at 2 dealers over the past 4 years: all together, stayed at least 12 months for repair, but nothing worked so far, and the second dealer gave up and asked me to take the car back.
FYI, I have the car for 7 years, and originally it was not doing that, but since GM changed the engine due to valve failure (!!), nothing but problems.

Have been changed to new (per GM dealer): battery, starter, alternator, cable line from battery to engine. I got the right exhaust pipe wrapped with insulation fiber and added an insulation plate to protect the starter from heat.... but nothing worked so far !!

Any help ?
Any address of Z06 mechanics in LA / SF that could have experienced and resolved this issue.
Thanks a lot
My situation (above) was resolved by replacing the starter. It lasted for 12 years. It all works great since replacing in 2018.
 

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Thanks Zippy for the info.
Do you or someone else know any good Z06 mechanics in LA / SF that could have experienced and resolved this issue and that you would recommend ?
Thanks a lot
 

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Discussion Starter · #8 ·
Thanks Zippy for the info.
Do you or someone else know any good Z06 mechanics in LA / SF that could have experienced and resolved this issue and that you would recommend ?
Thanks a lot
Sorry, no I don't. I'm in Toronto Canada and I take my car to Champion Motors, but maybe if you give them a call, maybe they know someone there. Champion Motors
 

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Have you solved this issue? did you find a good mechanic in the SF area?
I'm having the same thing with my 09 z06.
Thanks for following up.
The answer is .... Yes and No.

I was in contact with a GM dealer and another person from GM Corvette department.
Both confirmed the diagnostic (see below !!)

Here is the story.
After driving the car (C6 Z06 2008) 2000 ml over 15 months, in Dec 2013, engine broke due to valve falling in chamber.
After local Fresno CA GM denied it was an issue known by GM, engine was replaced by GM at no cost for me, besides $1000 for expertise and $500 (battery, etc).
Then started the second set of issues.
Very soon after, I had (and still have) issue to start the engine when hot. More specifically when engine is hot, if I stop for +/- 30 minutes (then temperature goes up) the starter, while cranking can barely make it. After few attempts, battery seems to die. The next day, when car has cooled down, the engine starts just like nothing happened.
In addition, interfering with this starting issue came several electrical issues: clock disappearing and coming back randomly, same for tire pressure gauge, same for windows up and down, etc, etc.

For the electrical part, local Fresno GM dealer found ground issues but problem still there, 8 years later.
Now regarding engine starting issue: starter, alternator, cable battery-engine, piston/valve sensors, etc, etc have been changed. I paid over $6000, but still dealing with the issue.
For the past 8 years (2013-2021), I drove the car 6000 ml, but the car spent a total over 72 weeks !!! ( 20 months+) over 14 visits to 2 GM dealers. No results whatsoever.

Finally, I have been recently in contact with a 3rd GM dealer, very nice, who was well aware of such issue: the answer was terrible news: Titanium on the rods is failing and eroding, circulating in the oil, and grinding the bearings apart over time... nice ! It was recommended that I proceed with an oil analysis. I did and the results confirmed that titanium levels in oil were very very high along with steel and aluminum particles. The 3rd dealer confirmed that GM was aware of this issue that occurred on LS7 engine during the period 2012-2014 (if I remember correctly) ... just when my engine was replaced by GM for the 1st time in 2013. The dealer indicated that very soon I will experience a catastrophic engine failure with the engine completely blocked due to the rod bearing issue !!! Only remedy: rebuilt or replace the engine (for the second time). The dealer also indicated that GM will most likely not replace this engine at their charge due to the age of this engine that was replaced in 2013....
This is where I am !!

Ever heard about that ? Any advice ?
Arno
 

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Thanks for following up.
The answer is .... Yes and No.

I was in contact with a GM dealer and another person from GM Corvette department.
Both confirmed the diagnostic (see below !!)

Here is the story.
After driving the car (C6 Z06 2008) 2000 ml over 15 months, in Dec 2013, engine broke due to valve falling in chamber.
After local Fresno CA GM denied it was an issue known by GM, engine was replaced by GM at no cost for me, besides $1000 for expertise and $500 (battery, etc).
Then started the second set of issues.
Very soon after, I had (and still have) issue to start the engine when hot. More specifically when engine is hot, if I stop for +/- 30 minutes (then temperature goes up) the starter, while cranking can barely make it. After few attempts, battery seems to die. The next day, when car has cooled down, the engine starts just like nothing happened.
In addition, interfering with this starting issue came several electrical issues: clock disappearing and coming back randomly, same for tire pressure gauge, same for windows up and down, etc, etc.

For the electrical part, local Fresno GM dealer found ground issues but problem still there, 8 years later.
Now regarding engine starting issue: starter, alternator, cable battery-engine, piston/valve sensors, etc, etc have been changed. I paid over $6000, but still dealing with the issue.
For the past 8 years (2013-2021), I drove the car 6000 ml, but the car spent a total over 72 weeks !!! ( 20 months+) over 14 visits to 2 GM dealers. No results whatsoever.

Finally, I have been recently in contact with a 3rd GM dealer, very nice, who was well aware of such issue: the answer was terrible news: Titanium on the rods is failing and eroding, circulating in the oil, and grinding the bearings apart over time... nice ! It was recommended that I proceed with an oil analysis. I did and the results confirmed that titanium levels in oil were very very high along with steel and aluminum particles. The 3rd dealer confirmed that GM was aware of this issue that occurred on LS7 engine during the period 2012-2014 (if I remember correctly) ... just when my engine was replaced by GM for the 1st time in 2013. The dealer indicated that very soon I will experience a catastrophic engine failure with the engine completely blocked due to the rod bearing issue !!! Only remedy: rebuilt or replace the engine (for the second time). The dealer also indicated that GM will most likely not replace this engine at their charge due to the age of this engine that was replaced in 2013....
This is where I am !!

Ever heard about that ? Any advice ?
Arno
I've not only heard it, I've experienced it to the most worse possible way and can confirm this story. The starter can have trouble when the engine is hot and you can solve it by shielding it from heat or replacing it with a high-torque starter, but we'll be fixing a symptom of the same root cause that I've experienced too: Rods rubbing each other away when hot. For others: If this might be your problem, then by NO means do you want to up the cranking power!

Both the failures happend to my bonestock '07 Z06, so the 1st (dropped valve) and 2nd (crank bearings) catastrophic failure which resulted into complete loss of oil pressure while riding hard. The end result was a loud grinding noise of metal particles in the engine with a heavy knocking noise of the loose crankshaft, like really heart chewing nasty. I still have a lawsuit running for 3 years now against the reseller of the crate engine which was supposed to be a '14 LS7. For that lawsuit to happen I had to hire an independent expert on the field of engines, and that's when it became interesting as the report was being documented. Yes, the same verdict you've gotten.

When the expert came into play for the 2nd failure when I lost my new engine after only 6k miles, his story was as followed: The titanium coating wasn't heat-treated properly on the rods which resulted into being rubbed away at the contacting surface between the rods, leaving Ti particles in the oil which in turn cause failure to all bearings. And yes, all bearings needed to be replaced, all 8 rods, some pistons (did all) and the complete engine+crank had to be machined. Then it also came into play that the '14 heads had the same defect as my original '07 engine's causing the dropped valve, so the valve guides also had to be replaced. The complete rebuild costed almost as much as a new engine, and that's only because it wasn't grenaded as was with my 1st catastrophic failure.

My solution? I wanted to keep everything original, so I've ordered a set of 2nd hand pre-2012 rods and pistons and doubled the oil changing intervals just to be safe. It's hard for me to regain trust, but I don't experience the inability to start the engine anymore when it's very hot. It just cranks a tad harder to a level where I don't hear anything worrying. The Ti-levels of the first oil changes were still high, but as I'm driving the car more it seems to diminish to safe levels. Still it can suddenly change as so many factors have to be accounted for, and I'll probably be forever letting the oil getting sampled. I'll be going LSX454 or C7 if more funny business is about to happen, but other options I can think of are:
  • Replacing the rods for something that doesn't rely on the Ti material and coating -> keep in mind that heavier internals should be combined with reevaluating its max rpm. The Ti rods are really light.
  • Reheat-treating the rods with a fresh coating of Ti -> first let it be confirmed that the old coating wasn't heat treated properly though, otherwise I suspect the internal frictions of the rods to be too high.

Also, the following can help potential owners as I'm very panicky and cautious when it comes to the engine. I have countless videos of troubleshooting and I believe I can safely give potential symptoms of failures:
  • Low oil pressure when cold -> My fresh engine gave a cold, idle oil pressure of 450 kPa (65 psi) on 5W-30 (dexos 2) @ ~15c oil temp. When its bearings were shot, it only gave 200-250 kPa (30-36 psi) in similar conditions and south of 100 kPa (15 psi) when warm.
  • Sudden change/huge drop in oil pressure when going WOT on hot engine -> crank bearing failure leaving particles in the pick-up lines clogging them up.
  • Stalling of the engine when hot at low rpms -> rubbing of the Ti rods, but could also be a vacuum/MAF/MAP/O2 sensor issue.
  • Hard cranking when engine is hot to the point that the starter stops for a sec/not at all/DTC failures appear/car bricks itself for 15 min -> could be rubbing of the Ti rods, check oil samples asap.
  • Heavy swirls and/or clearly visible glitters in the oil, especially if they're copped-colored -> that's probably bearing material you're seeing. Expect to have too high Ti levels.
  • Engine sounds different than usual -> louder than usual sewing machine noise could indicate the valve guides are failing, a knocking noise around 2-3k rpm could indicate crank bearing failures.

This is the data I've compiled regarding the starter and rods, so I hope it can be of use to anyone.
 

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This season, my 2006 Z06 has had trouble starting when it is up to temperature (and it gets worse when it is hot outside).
When the car is cold, it starts up no problem, but when I'm doing multiple starts/stops (errands, etc), it can actually get to the point where it won't start.
Has anyone come across this?_ If so, please share how you solved it.
One thing I have heard is that it could be the starter motor, somehow getting worn or increasing friction when it is warm.

It's not the battery, not the alternator._
I have had both tested, and they are in perfect shape.__
When I thought it might have been one of those issues, I was putting a trickle charger on between using it. However, it wasn't the extra charge it needed, it just needed to cool down.
When I had the battery and alternator tested after the car wouldn't start, I left it for an hour, and it started (with a little hesitation since it was still a bit warm).

Any thoughts/tips would be appreciated.
I would suggest spending the money and getting it checked at a Chevrolet dealership.

I had an 01SS that was doing exactly what you are describing, it was a pain in the ass my mechanic and I made many replacements to no avail.
I went to the dealer, they have way smarter and more modern systems as opposed to those hand held plug into that underneath the dash thing and they found out it was the cam positioning sensor?
No code ever came up but once that sensor was replaced there were no problems after.
I’m not saying you have the same issue but the dealer will be able to figure it out a lot faster.

prior to taking it to the dealer I replaced the plugs and wires and fuel pump and fuel filter and the fuel lines to no avail, and all that shit cost me bucks when I might have saved by going to the dealer.
My .02
 
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