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C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
I started losing coolant out of the reservoir I noticed a few days ago. I filled the system back up and drove about 60-70 miles over a couple of days and the reservoir is almost empty again. I pulled the dipstick and the oil looks normal but the cap looks bad. The coolant reservoir dosent appear to have oil in it.
About a month ago there was a small puddle of dexcool on the garage floor about where the middle/passenger side of front engine area, i looked for a leak but found nothing, and I havent seen any puddle since that day.
Sometimes i can smell coolant burning especially if the car gets over 200f I cant tell if its from the engine bay or the exhaust, Im running catless so the normal exhaust smell is strong.
Whats else can I check to verify Its a headgasket?
Car is on the stock cam and I replaced the heads last may with AHP no milling and arp bolts. It runs very strong and idles fine. Just rolled over 30k.
Most likely it is in fact a blown headgasket. You can do a very quick and simple leak down test and coolant pressure test and this will help identify it. These testers are cheap (less than $50) and can be purchased on Amazon or Harborfreight or Autozone. Pressurize the coolant system and see if it holds pressure. You can also use something called a "block tester", which is a quick and cheap chemical test kit. It basically can determine whether combustion gases are present in the cooling system — a good sign of a head gasket failure
Headgasket. My heads are coming off as we speak and going back to stock LS7 HG's. I had Cometic's and under my valvecovers look like milkshake from coolant and oil mixing. Hopefully I have time to pull heads over the next couple of days to see the gaskets and the mating surfaces.
Also, did you clean the deck of the block well? I assume the heads were new looking when AHP sent them back to you so you should be ok there.
Yes cleaned the block off very well. I used the new headgaskets ahp send and didnt reuse any hardware. I torqued everything to spec, I work on boeing 737s and cfm turbines so Im very familiar with torque sequences and instructions.
Ill look into getting a pressure tester. If I gotta pull the heads again Im putting a cam in it.
Works good, seals up nice, is accurate and is cheap. Once connected and pressurized, if the pressure drops (sitting with car off) and you don't see an obvious coolant leak then it is probably the head gasket. You can also test it by turning the car on with the tester hooked up (no pressure on it initially). If there is an immediate and rapid build up in pressure then that also suggest head gasket.
I would NOT pull it apart until I found the source of the antifreeze on the floor. I would pull and inspect the spark plugs and inspect the tops of the pistons with a scope while the plugs are out. Check the water pump. Check all your hoses and connections. You should really confirm where it's going before you pull it apart. Would really suck to pull it apart and find nothing wrong.
On a properly put together setup, it is actually pretty hard to blow a HG in my experience. Much easier to crack the block. So make sure you very very closely inspect the cylinder walls/block. I've seen it too many times when people think it is a HG, swap HGs, and still have same issue, to only find later a crack in a liner. Had a friend that would lose coolant and have same symptoms as you only when car was warm. When it was cold the crack would actually seal up and it would open up when warm. Was very hard to see the crack.
I hope so to, but on these cars detonation typically takes out block/liner before HG. Only way I've seen a HG fail on a <850rwhp car is improper installation like not cleaning enough, rough surface finish, etc.
After using a pressure tester i found the leak. This t_fitting and it drips right onto the cooler right below it. I guess it seals up when hot because everytime id check it, it was bone dry.
Still dosent explain the milky oil cap.
So friggin relieved. Thanks for all your help guys.
Is the engine missing?
What do the spark plugs look like?
Does the car blow white smoke out the exhaust?
Have you run a compression test and if so, what were the results?
Have you checked the cap on the reservoir to see if it's functioning properly?
As someone else said, I would not tear that engine down unless 1) a compression test shows a low cylinder, 2) coolant test for combustion gases shows positive and/or 4) you do not find the source of the leak which left coolant on the ground.
02-27-2019, 05:32 PM
I think I have a blown headgasket.
