esch

Hi, So I think I may have a head gasket leak, but it's not obvious. Looking for some opinions.

Info:

- '01 C5, I'm the original owner. Daily driver.
- 122K on the car.
- Back at ~40K we yanked the motor, built it up with mostly GM performance parts and bolted on a Procharger.
- The heads (of course) were pulled and worked up at that time.
- Just recently I have been seeing fluid on the Garage floor. Dripping down directly below the starter. About a 10" puddle each time. Its been seen about 10 times now.
- Oddly I don't see a puddle everyday, more like every 5th day. It is entirely possible only on very warm days. Every day it goes with me to work, 30 min drive.
- Oil looks perfect, no signs of water in the oil, but it has not been tested.
- Looking at the head it "seems" like the seam around the bottom of the head, around the lower part of the head gasket is wet, but I can't say for sure.
- NO indication that coolant is making it into the cylinders. No white smoke / steam and I've only had to add coolant one time, consistent with the amount lost on the floor.


Now what makes me pause is that there is clearly fluid near FRONT corner of the head at the head gasket (remember the leak seems to drip at the rear of the motor). Of course this could be just wind effect. Or perhaps its unrelated from a wet motor due to rain.

Questions:

A) is there anything at the rear of the motor that could leak coolant that I might not be able to see easily? The heater tubes do NOT seem to be the issue (though I can't absolutely say that yet). Is there a valve or a seal or a ??? that might be the cause of the leak?

B) I have changed my fair share of head gaskets before but never on the LS1. I tend to leave what's not broke alone but would anyone suggest that if I end up doing one head gasket to go ahead and do both?

C) If there is truly no water in the oil am I OK to drive this car? or is there a pretty high risk that its just a matter of time and that soon the oil will get water in it?

D) Assuming I will be taking the head(s) off, is there any other task I should plan to tackle whlie I'm in there? The engine seems perfect other than this issue.


My next move is to do a pressure test on the cooling system to see if I can find that leak point. It just seems like a weird leak.

OK, that's a long enough post. Any thoughts kids?

zachaeous

There are fitting on the back of each head that have a metal with rubber seal in it on my 2001. They look like the front crossover tube on the front of the heads. It is possible that one on the passenger side is leaking and running down.





there are fitting on the front and back of the heads regardless if they have a line between them.

Hope this is clear. Good luck with your repair

esch

Thanks - I just went out to look. I can see the top of those fittings, but being able to see well enough to tell if there is a leak there is gonna be tough. I may need to break out the bore scope.

I will update this this thread as I find out more.

esch

OK, So I ran a pressure test today. Losing about 1 PSI/min. That in itself is not conclusive but it would have been better if I didn't lose any PSIs.

I ran a bore scope around the head gasket seem. Leak is nearly impossible to detect a location but I can say that the pressure resulted in about 1 drip hitting the ground per min. But telling exactly where it is coming from is not gonna happen, at least not without throwing dye in the system and I still don't really think that will help.

The thing is that I cannot see the back of the engine block really at all, even with the scope. But its what I can see that leaves me to conclude its the head gasket because I can see the fitting on the top of the head, it looks dry. And I can see the heater core tubes pretty well and they look dry.

What has me second guessing still is that the head gasket seems wet all along the bottom edge of the head, from front to back, yet it is only dripping from the back of the motor.

I think I'm screwed. I think I need to pull the head.


So back to my original questions above. Do I pull both heads? Do I drive it?

zachaeous

I would try a good brand of stop leak and run the car. I managed a fleet of over 200 vehicles for over thirty years and this included a lot of different types of vehicles. We had great success with coolant leaks that were not entering the combustion chambers. If you are positive that you are not getting coolant into any cylinders I would give the above a try. This is just IMHO but I think it would be worth a try. Good luck with whatever you choose to do.

BigGun

I would want to be SURE it was a head gasket before a major job like pulling the heads. If it is not overheating I would just drive it. The leak will probably get worse and be easier to locate.

k24556

Here is a suggestion: get some water soluble flourescing dye Like Sherwin Aqua chek wb-100, and buy a cheap LED blacklight flashlight on fleabay. The company I worked for before I retired bought this dye in 5 gallon containers and it was cheap. Maybe you could beg a small sample or ask where to get a small quantity from the source below. A little goes a long way.

Then, pour some in the coolant system and use the blacklight flashlight to source the leak. I bought one of the little LED blacklight flashlights on fleabay for $4 shipped for tracing leaks in the AC system. worked great.

http://www.bergeng.com/Sherwin-AQUA-...-100-prod.html

runner140*

That was my first thought. Pressure test first.

BigGun

He did. See post #4.

tbrowne

Pull the intake manifold. It's not difficult and you'll be able to see much more than with it in place. Unlike the older small blocks, there is no coolant connected to the LS intake, so no worries there.

ascastil

Block test?

renegade123

Check your water pump/gaskets,..water like oil travels , playing mind games when trying to figure out where the actual leak is....easy enough to do rather quickly..If not then most likely a hose leaking I would think....Any "sizzling " sounds like water hitting hot metal ??

Turbo-Geist

I had something similar happen. 800 rwhp stock LS1 twin turbo with factory original gaskets and torque to yield head bolts. It had around 86,000 miles on the engine.

For about 3 months I would notice a very small quarter sized puddle of coolant on the garage floor after a weekend of racing. It was on the driver's side and eventually started being visible on the motor mount and cradle. The car still ran very strong and no coolant was mixing with the oil.

I took it out for a race one night and the engine failed at around 160 mph.

https://www.corvetteforum.com/forums...th-a-bang.html

esch

Pulled the heads. What we found was pretty much criminal.

Sure enough pulling the heads told the story:

Now, I did not do this job myself. I can, but better leaving this car to someone who does this all day long. So I take it in, they pull the heads and the machine work that had previously been done on the heads was the worst surfacing I have ever seen. Looked like it had be done with a hand grinder (I'm not mentioning who did that work! - they are no longer in business). - I am surprised the heads weren't leaking right from the start after that build. The good news was that there was no water in the oil.

The heads have been newly machined, with new springs and the motor is finally back together.

I should have the car back soon. Looking forward to some summer driving.


(sigh)