Coolant leak?
Thread Starter
Melting Slicks
Joined: Jan 2010
Posts: 2,024
Likes: 4
From: Austin TX
Coolant leak?
I've been getting a Low Coolant light for a while now on my 88 coupe, and in spite of my attempts to fill my radiator, it doesn't seem to want to go away. I think by now I've put about 2 gallons in, and it still reads low. I haven't found any evidence of a leak under the car, so I'm thinking it's possible it's leaking into the engine. What would be some signs to look for as evidence of this?
Drifting
Joined: Jun 2010
Posts: 1,853
Likes: 8
From: Westerly RI
If you have put two gallons into the cooling system, and haven't found a leak, you should suspect a substantial head gasket failure, or a cracked head. You didn't say how over how many miles the 2 gallons have been added, but that is a lot of coolant. A symptom is white smoke from the exhaust after the engine is warmed up. You could do a compression test. You may be able to smell exhaust in the coolant. There are chemical test kits that go in the cooling system to check for combustion gases. The only places the coolant can go are on the ground or out the tailpipe.
Thread Starter
Melting Slicks
Joined: Jan 2010
Posts: 2,024
Likes: 4
From: Austin TX
So the smokescreen would be noticeable out the rear hatch? I'm not sure how long the coolant has been low. I've been getting the light off and on for a few months and have been periodically trying to understand how the system works and fill it. I've only recently been aggressively filling it with water to give me some extra time, so I can do a full system flush like I've been meaning to do.
Drifting
Joined: Dec 2004
Posts: 1,313
Likes: 5
From: Middle Tennessee
Wow! That's a lot of coolant to pump through your combustion chambers! Hope it hasn't done too much damage. If there hasn't been any anti-freeze puddles under the car, then a head gasket or cracked head is just about the only other culprits, that is unless you have a pin-hole leak in one of your radiator hoses that only leaks under pressure. Pray for the radiator hose leak as it is a lot less expensive to correct. I'll cross my fingers for you!
Drifting
Joined: Aug 2006
Posts: 1,624
Likes: 2
From: Canandaigua New York
You need to do a pressure test on your cooling system.
If there is a leak, that will find it.
Also check your radiator cap to see if it's weak.
A good radiator shop can check both for you.
If there is a leak, that will find it.
Also check your radiator cap to see if it's weak.
A good radiator shop can check both for you.
Thread Starter
Melting Slicks
Joined: Jan 2010
Posts: 2,024
Likes: 4
From: Austin TX
Wow! That's a lot of coolant to pump through your combustion chambers! Hope it hasn't done too much damage. If there hasn't been any anti-freeze puddles under the car, then a head gasket or cracked head is just about the only other culprits, that is unless you have a pin-hole leak in one of your radiator hoses that only leaks under pressure. Pray for the radiator hose leak as it is a lot less expensive to correct. I'll cross my fingers for you!
Any tips on a good, proper way to fill the system? Like, car jacked up on one side, hot, cold, running?
The coolant at the top also has a bubbly brownish look to it.
Last edited by Azriel; Mar 10, 2011 at 11:36 PM.
Drifting
Joined: Jun 2010
Posts: 1,853
Likes: 8
From: Westerly RI
I've noticed on one of the hoses what looks like condensation. That could very well be it! I haven't noticed any sort of pressure any time I've opened the system. I'll look into a new cap and a new hose.
Any tips on a good, proper way to fill the system? Like, car jacked up on one side, hot, cold, running?
The coolant at the top also has a bubbly brownish look to it.
Any tips on a good, proper way to fill the system? Like, car jacked up on one side, hot, cold, running?
The coolant at the top also has a bubbly brownish look to it.
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Team Owner
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
The coolant at the top also has a bubbly brownish look to it.
You can rent a pressure tester at AutoZone (no charge) and it will also test the cap's ability to hold pressure. If it won't hold pressure, get a cap with the specific pressure rating the car needs. Think it's a 15 lb cap so don't get one with a pressure range;
You have to find the leak before it gets bigger or does damage.
To fill the cooling system, run the engine without the pressure cap on. Then increase the idle to around 1100-1200 RPM. This should cause a drop in the coolant level in the radiator. Continue to fill until the coolant is right at the base of the filler neck and stays there. Replace the cap and let the engine for a few minutes, keeping an eye on the coolant temp. Make sure the overflow bottle has coolant in it and at the "HOT" level.
