Dwebby

Greetings Corvette experts,

Two days ago I bought an '06 Z06 with 37k miles on it. Midway through my 600-mile drive home the engine temp gauge shot through the roof accompanied by some metallic rattling noise (sounds like a paper clip rattling inside an empty tin can) whilst doing 80 mph @ 4,000 rpm. I immediately pulled off the interstate and shut the car down. After limping it to a close by mechanic shop, the oil is chocolate milk (coolant mixed with oil). My assumption is that the head gasket failed possibly due to dry rot or hard abuse by prior owners. It is an HCI car (Heads, Cam, Intake) and very clean inside and out. Typically signs of abuse are easy to spot but during test drive this car idled smoothly (no knocks or ticks) with clean shifts, clean revs, crisp braking, and easy startup.

I do not know the cam specs but the heads are CNC ported West Coast heads. Also has Katech valve covers with coil pack relocation kit and a 102mm intake.

Based on symptoms I am thinking head gasket, but want to know what other key elements need to be checked once the heads are removed. Lifters, pushrods, springs, pistons? If it is simply a head gasket, what should I expect in terms of cost?

Thank you in advance for any advice and info!

Jayfabs

Were you doing any pulls?

Dwebby

pjazz

I'd say if the heads are going to be removed all the above should be checked. Just a head gasket repair just a guess about $1700 parts and Labor?

pjazz

To me it almost sounds like the dealer might of done a shoddy job.

mdopole1

Head gaskets are around 50 dollars each. No way that a 1700 repair. Lol should be even cheaper if its just the passenger side.

pjazz

Hey that was just my guess. I'm sure someone who's had it done can chime in.

Undy

Sad to say it's probably a cracked cylinder liner (which is much more common that a blown head gasket). This is especially true with a HCI (tuned) car. One of the Z06's Achilles heels is their thin and weak cylinder liners. Pulling the heads will tell the story.

Unreal

Rare to see a head gasket go. Piston/block typically goes first.

Dwebby

I previously owned a C5Z that was HCI tuned. That one broke a quarter-sized chunk off the head near the spring while I was cruising home from work one day. I certainly hope your prediction is incorrect this time around.

GTAZ06

A leaking fuel injector o-ring on the rail side would cause an external fuel leak. A leaking o-ring on the manifold side would cause an air leak. No additional fuel would be added to engine except to correct a lean condition if in fact there was an unmetered air leak. Possible that before the repair, a cylinder was chronically lean and was detonating. Damage may have already occurred unknowingly. Though if this was the case, an a/f metering code should have been present at some point. Just a thought...

Dwebby

Good call out. The leak was severely external. I suddenly smelled fuel while driving on the interstate. I immediately pulled off and popped the hood to see fuel spraying all over the engine bay from two of the passenger side injectors. Major fire hazard. When I had it towed to the dealership I had them replace all 8 rings top and bottom. When I rolled it into the mechanic shop later that day with the engine problem, one of the injectors was leaking again. All of this happened on a long road trip home so I was not in a position to hang out and call places/wait several days so I had to leave it at the shop and rent a car to get home.

KurtsZ06

Time to have a very hard conversation with the dealer that sold you the car. As Is condition is one thing, consumer law protects you in situations like this.
If me, I’d have the dealer buy it back or, learn a very potent lesson in tort law.

Unreal

80mph@4000rpm yet never got on it? That makes zero since, as 80mph should be 1700-1800rpm, unless you are downshifting and getting on it.

Dwebby

I left it in 4th and climbed to around 80 and kept it there. I know better than to downshift hard at a healthy clip. Climbing to 4k and maintaining for several minutes is not even a hard run. Thats just driving in the low-mid range of the power band and definitely shouldn't be enough to blow a healthy motor.

KurtsZ06

My point exactly ... you didn’t start with a healthy engine. The fuel injector leaks alone demonstrated that. Dealers are required by law to do safety inspections of the cars they sell. This dealer did the minimum if any at all.

mdopole1

Sorry wasnt trying to be rude. Just thought you might have added a additional zero to that figure on accident or something. Id guess with parts and labor that it would be under 500 for both headgaskets to be replaced. Possibly cheaper.

pjazz

No worries I still think with parts and labor head removal and gasket replacement done right isn't cheap unless you do it yourself. I hope the OP isn't looking at something worse.

MTPZ06

Get out of this car while you can. IMO, when a modified car ends up on a dealer lot (H/C/I), its because the owner most likely had to dump it.

Dwebby