Coolant loss
Thread Starter
Pro
Joined: Mar 2006
Posts: 700
Likes: 2
From: Spring Hill Florida
Coolant loss
About once a week I have to add coolant. Today I rented a pressure tester, pumped it up to the required lbs. and it held. There is no water in the oil so I guess that means it's getting into the engine somewhere? My question is before I tear it down, would a stop-leak in the raditor work? If it's a gasket would that seal it? I know I'm just woofing myself but it's worth a try? 
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
It could be the early stages of a blown head gasket. Suggest you pull plugs #7 and #8. These are the cylinders with a higher gasket failure rate than others. If one looks very clean compared to the other....chances are it is the head gasket. It will get worse over time if it is.
Burning Brakes
Joined: Oct 2001
Posts: 911
Likes: 5
From: TN
recovery tank
Where are you adding the coolant, the recovery tank because it is low or removing the radiator cap to check coolant?
A normal system will discharge coolant from a full engine/radiator into the recovery tank during substained driving and with overnight cooling and not being driven the coolant will be pulled back into the radiator.
A normal system will discharge coolant from a full engine/radiator into the recovery tank during substained driving and with overnight cooling and not being driven the coolant will be pulled back into the radiator.
Safety Car
Joined: Aug 2013
Posts: 4,427
Likes: 603
From: Minneapolis Mn
Coolant loss
First thing I'd do is put some paper under the car after it's been driven and see if anything gets wet over night. After sticking the paper under it, while it's still running, lift the hood and look for any wisps, though I doubt any with the little you're losing.
Another area some have had issues with is the heater core. Check around it for wetness. Maybe run the defroster and see if anything shows up on the windshield.
Unless it's new, I would change the radiator cap anyway. I had one that would hold pressure but wouldn't hold the seal to suck the coolant back from the reservoir as it cooled.
Another area some have had issues with is the heater core. Check around it for wetness. Maybe run the defroster and see if anything shows up on the windshield.
Unless it's new, I would change the radiator cap anyway. I had one that would hold pressure but wouldn't hold the seal to suck the coolant back from the reservoir as it cooled.
Intermediate
Joined: Jun 2006
Posts: 29
Likes: 0
From: Pahrump NV
I had a similar problem with an '85. I bought it from a fellow who complained that it overheated around town. When I got it home I checked the radiator, and it was empty, so I filled it. Car ran fine. I checked the level in the radiator after a while (Days) and the coolant was a little low. I figured I hadn't gotten it full the first time and so I topped it off. A couple of weeks later and it was down a little, so I started checking things, to no avail.
Then one day I noticed a thin trickle of coolant at the rear of the block on the pass side. I called a friend who was "the man' at the largest Chevy dealer in LV. He said they all do that, Alum head, steel block. I asked how much to fix, he said "$30 for gaskets, $1000 or more for labor, cuz you have to take the whole top of the engine off". He talked me into doing it, and it was a bitch. But I got'er done, and all was forgiven.
The other problems I had with the coolant in this car was 1) replaced thermostat witha 180 Robertshaw, and 2) pitched the radiator cap in the bushes and bought the correct one from GM. 25,000 miles later and no problem.
I don't know if any of this will help,but it's the simple things that can hurt you!
Then one day I noticed a thin trickle of coolant at the rear of the block on the pass side. I called a friend who was "the man' at the largest Chevy dealer in LV. He said they all do that, Alum head, steel block. I asked how much to fix, he said "$30 for gaskets, $1000 or more for labor, cuz you have to take the whole top of the engine off". He talked me into doing it, and it was a bitch. But I got'er done, and all was forgiven.
The other problems I had with the coolant in this car was 1) replaced thermostat witha 180 Robertshaw, and 2) pitched the radiator cap in the bushes and bought the correct one from GM. 25,000 miles later and no problem.
I don't know if any of this will help,but it's the simple things that can hurt you!
Thread Starter
Pro
Joined: Mar 2006
Posts: 700
Likes: 2
From: Spring Hill Florida
Thanks for all the suggestions. I had a hydro lock a few years back and after pulling the plugs saw liquid run out of one of the plugs. Sure enough it was a blown head gasket. And you are right it was over $1,200 to fix it. I've replaced the cap, pulled the overflo tank and cleaned it. The tank stays full but I still need to fill into the raditor; so why doesn't it pull from the overflo tank? Maybe the new cap is bad? I'm going to pull the plugs and take a look. Again, thanks...
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
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
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Drifting
Joined: Feb 2008
Posts: 1,537
Likes: 177
From: NE Ohio
2024 C4 of the Year Finalist - Unmodified
Thanks for all the suggestions. I had a hydro lock a few years back and after pulling the plugs saw liquid run out of one of the plugs. Sure enough it was a blown head gasket. And you are right it was over $1,200 to fix it. I've replaced the cap, pulled the overflo tank and cleaned it. The tank stays full but I still need to fill into the raditor; so why doesn't it pull from the overflo tank? Maybe the new cap is bad? I'm going to pull the plugs and take a look. Again, thanks...
Me too and it was the cap! Make sure you get a good cap and not a cheap one!
Melting Slicks
Joined: Jan 2009
Posts: 3,181
Likes: 286
From: Puyallup Washington
I would not use one unless there was no other choice. I have used them on cheap cars that it was not worth replacing the radiator and they worked.
If your radiator is losing water but the overflow stays full you may want to check the line between the radiator and the overflow as they sometimes get plugged with junk and there is no water movement through the line. Check the radiator cap. Check around the radiator cap for cracks in the radiator.
If your radiator is losing water but the overflow stays full you may want to check the line between the radiator and the overflow as they sometimes get plugged with junk and there is no water movement through the line. Check the radiator cap. Check around the radiator cap for cracks in the radiator.
Burning Brakes
Joined: Oct 2001
Posts: 911
Likes: 5
From: TN
1985 Corvette
I had a similar problem with an '85. I bought it from a fellow who complained that it overheated around town. When I got it home I checked the radiator, and it was empty, so I filled it. Car ran fine. I checked the level in the radiator after a while (Days) and the coolant was a little low. I figured I hadn't gotten it full the first time and so I topped it off. A couple of weeks later and it was down a little, so I started checking things, to no avail.
Then one day I noticed a thin trickle of coolant at the rear of the block on the pass side. I called a friend who was "the man' at the largest Chevy dealer in LV. He said they all do that, Alum head, steel block. I asked how much to fix, he said "$30 for gaskets, $1000 or more for labor, cuz you have to take the whole top of the engine off". He talked me into doing it, and it was a bitch. But I got'er done, and all was forgiven.
The other problems I had with the coolant in this car was 1) replaced thermostat witha 180 Robertshaw, and 2) pitched the radiator cap in the bushes and bought the correct one from GM. 25,000 miles later and no problem.
I don't know if any of this will help,but it's the simple things that can hurt you!
Then one day I noticed a thin trickle of coolant at the rear of the block on the pass side. I called a friend who was "the man' at the largest Chevy dealer in LV. He said they all do that, Alum head, steel block. I asked how much to fix, he said "$30 for gaskets, $1000 or more for labor, cuz you have to take the whole top of the engine off". He talked me into doing it, and it was a bitch. But I got'er done, and all was forgiven.
The other problems I had with the coolant in this car was 1) replaced thermostat witha 180 Robertshaw, and 2) pitched the radiator cap in the bushes and bought the correct one from GM. 25,000 miles later and no problem.
I don't know if any of this will help,but it's the simple things that can hurt you!