What is leaking here?
Thread Starter
Burning Brakes
Joined: Dec 2004
Posts: 918
Likes: 5
From: Gainesville FL
What is leaking here?
I've had a nagging coolant leak on my L98 that doesn't allow the excess coolant to be pulled up from the overflow tank as the motor cools. I expected this to be a simple fix like all the others I've done on my other cars. I put a pressure tester on the car and left it overnight. I found liquid on the garage floor just forward of the oil filter. Should be easy now, right? What was weird was that the color was less green than the coolant in the car, like it had been diluted by about half. The liquid on the floor also felt pretty slippery. Two questions:
1. What else besides coolant could leak from a motor when the cooling system is pressurized to 16 psi with a pressure tester? Or is there some other reason that the coolant that leaked out would look different than what's in the radiator?
2. Assuming that the liquid on the floor was coolant, where should I look for the leak, given its location on the floor (about 6" in front of the oil filter)?
1. What else besides coolant could leak from a motor when the cooling system is pressurized to 16 psi with a pressure tester? Or is there some other reason that the coolant that leaked out would look different than what's in the radiator?
2. Assuming that the liquid on the floor was coolant, where should I look for the leak, given its location on the floor (about 6" in front of the oil filter)?
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
1. Perhaps the coolant reacted with the concrete.
2. What year Vette? Do you have an oil cooler? Have you checked on the block below the VCs? Have you checked below the knock sensor & the temp sensor on the lower RH side of the block?
2. What year Vette? Do you have an oil cooler? Have you checked on the block below the VCs? Have you checked below the knock sensor & the temp sensor on the lower RH side of the block?
Safety Car
Joined: Oct 2007
Posts: 3,816
Likes: 0
From: :45 minutes from everywhere / E-I-E-I-O
I've heard of several leaks on L98 at intake near driver's side rear cylinder (#7?). I had one there too. Just a few drops, not always either. It was so small leak, I found it only when I pulled my intake for gasket swap/cleanin'...
Mine ran SO much stronger after did it too. And the vacuum leak went away too, which I NEVER did find.
Mine ran SO much stronger after did it too. And the vacuum leak went away too, which I NEVER did find.
Safety Car
Joined: Jan 2004
Posts: 3,783
Likes: 15
From: Northern California
Look for a leak on top of the front intake manifold bolts also, the waterpump could leak and drip back towards the oil filter area.
Last edited by GKK; Jul 27, 2008 at 02:34 AM.
Thread Starter
Burning Brakes
Joined: Dec 2004
Posts: 918
Likes: 5
From: Gainesville FL
Thanks for the advice, guys. I have to clean out the garage a bit before I can put it up on jack stands and re-run the pressure test to look underneath. I should have mentioned that the car is an 89.
I was thinking about the intake manifold as well. I'm really hoping that it's not the head gaskets, but I'll deal with whatever it is.
I was thinking about the intake manifold as well. I'm really hoping that it's not the head gaskets, but I'll deal with whatever it is.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
When I was searching out a mysterious oil leak I found that a VERY strong (zirconium I think) light and mirror were very useful for getting a view of hard to reach areas.
If an intake leak you should be able to see/feel where it's leaking.
BTW, have you checked the tube to the overflow tank and the tank for blockage?
If an intake leak you should be able to see/feel where it's leaking.
BTW, have you checked the tube to the overflow tank and the tank for blockage?
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
coolant
there's only five reasons why the coolant will not suck back into the tank.
1. a hose / gasket leak (you will be able to see that one clearly)
2. the cap is bad on the radiator, and the check valve is stuck closed.
3. the hose from the tank to the radiator has a crack or split in it, or the clamps are loose.
4. there is an obstruction in the hose from the radiator to the tank
5. the tube inside the tank has cracked and won't allow the radiator to suck anything but air.
check em out, the most likely ones are the radiator cap and the hose. most likely, it's the 20 year old hose.
1. a hose / gasket leak (you will be able to see that one clearly)
2. the cap is bad on the radiator, and the check valve is stuck closed.
3. the hose from the tank to the radiator has a crack or split in it, or the clamps are loose.
4. there is an obstruction in the hose from the radiator to the tank
5. the tube inside the tank has cracked and won't allow the radiator to suck anything but air.
check em out, the most likely ones are the radiator cap and the hose. most likely, it's the 20 year old hose.
Thread Starter
Burning Brakes
Joined: Dec 2004
Posts: 918
Likes: 5
From: Gainesville FL
Update on the leak. I tried for a month to find it on my own without success. I took it to a very good shop this morning and got the call a few hours later that it's a head gasket leak, just above the freeze plug at the back of the driver's side cylinder head. It had to get hot to leak, and then the coolant would evaporate, but you could see the white streaks where it had been coming out. Guess who's getting new head gaskets. At least that answered my wife's question, "What are we going to do with our economic stimulus check?" 
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
