Perplexed - Coolant disappearing
Thread Starter
Racer
Joined: Jan 2003
Posts: 321
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From: Birmingham AL
Perplexed - Coolant disappearing
New Vette owner - 92 LTI - Coupe
I've been diagnosing heater problem now that it's cold here. With your help I changed the t-stat to 160 Deg., flushed the coolant system, refilled the coolant system with 50/50 mix.
I have had a problem with the coolant disappearing. I have to add about a quart every two days. My low coolant light will illuminate telling me it's time to add. I have noticed that my heat does not work very well. While at idle, the air coming out of the vents is cool. While accelerating, the air will warm immediately. I don't understand where the coolant is going. Periodically I can smell coolant. It happens mainly when I stop at a light. I can find no leaks under the hood and the car is parked in the heated basement and there are no signs of leaking coolant on the floor.
Is it normal for the heat to increase under acceleration ??
I was told there was a check valve / orifice in the hose between the water pump and the expansion tank. Mine does not have one. Does it matter ??
Where can this much coolant be going without any evidence of a leak ??
Thanks in advance for any help. This problem has really been a PITA...
Jim
I've been diagnosing heater problem now that it's cold here. With your help I changed the t-stat to 160 Deg., flushed the coolant system, refilled the coolant system with 50/50 mix.
I have had a problem with the coolant disappearing. I have to add about a quart every two days. My low coolant light will illuminate telling me it's time to add. I have noticed that my heat does not work very well. While at idle, the air coming out of the vents is cool. While accelerating, the air will warm immediately. I don't understand where the coolant is going. Periodically I can smell coolant. It happens mainly when I stop at a light. I can find no leaks under the hood and the car is parked in the heated basement and there are no signs of leaking coolant on the floor.
Is it normal for the heat to increase under acceleration ??
I was told there was a check valve / orifice in the hose between the water pump and the expansion tank. Mine does not have one. Does it matter ??
Where can this much coolant be going without any evidence of a leak ??
Thanks in advance for any help. This problem has really been a PITA...
Jim
Burning Brakes
Joined: Jan 2002
Posts: 893
Likes: 0
From: Liberal Kansas
Re: Perplexed - Coolant disappearing (jimswhite92)
I am no expert and have not had this problem with my vette but have had symptoms like yours with my Range Rover. I was loosing coolant and had no external leaks that I could see. Heat would only work under increased RPMs. That was caused by not enough coolant in the system. If you can smell coolant is it coming from your exhaust? My problem was a head gasket. Could be you heater core. Might pull up the carpet and see if its wet under there. I know the lt1 has bleed screws that I know nothing about so you could have some dead space in your system .
Things you might check.
If the coolant smell is coming from your exhaust check your oil for coolant. It will look milky. Have a shop do a cylinder leak down test. I have herd of this but have not seen it in person but some shops can use a sniffer on your cooling system to see if there is any combustion gases present
[Modified by Rob90, 2:14 PM 1/25/2003]
Thread Starter
Racer
Joined: Jan 2003
Posts: 321
Likes: 0
From: Birmingham AL
Re: Perplexed - Coolant disappearing (Rob90)
Checked ... carpet not wet. I feel that if it was the heater core leaking that much I would have a strong odor in the car and the windows would probably fog from the inside.
Thanks for the input. :cry :cry :cry
Thanks for the input. :cry :cry :cry
Thread Starter
Racer
Joined: Jan 2003
Posts: 321
Likes: 0
From: Birmingham AL
Re: Perplexed - Coolant disappearing (SurfnSun)
This is a LT1. I checked the oil and it looks clean. Just had the oil changed. Ran the car for 20 miles. Checked the oil again, looks very clean on the dip stick.
Wow ... you would think I could see leak.
What's more mind boggling is the car sat all night last night in the garage. I checked the oil at 2:30 CST. I also took off the cap to add coolant. When I released the cap safety switch, the system still had pressure in it. You would think it would be void of any pressure if it was leaking.
Thanks for any help..... :crazy: :crazy: Jim
Wow ... you would think I could see leak.
What's more mind boggling is the car sat all night last night in the garage. I checked the oil at 2:30 CST. I also took off the cap to add coolant. When I released the cap safety switch, the system still had pressure in it. You would think it would be void of any pressure if it was leaking.
Thanks for any help..... :crazy: :crazy: Jim
Team Owner
Joined: Aug 1999
Posts: 24,017
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St. Jude Donor '10
Re: Perplexed - Coolant disappearing (jimswhite92)
This is a LT1. I checked the oil and it looks clean. Just had the oil changed. Ran the car for 20 miles. Checked the oil again, looks very clean on the dip stick.
Wow ... you would think I could see leak.
What's more mind boggling is the car sat all night last night in the garage. I checked the oil at 2:30 CST. I also took off the cap to add coolant. When I released the cap safety switch, the system still had pressure in it. You would think it would be void of any pressure if it was leaking.
Thanks for any help..... :crazy: :crazy: Jim
Wow ... you would think I could see leak.
What's more mind boggling is the car sat all night last night in the garage. I checked the oil at 2:30 CST. I also took off the cap to add coolant. When I released the cap safety switch, the system still had pressure in it. You would think it would be void of any pressure if it was leaking.
Thanks for any help..... :crazy: :crazy: Jim
Burning Brakes
Joined: Jan 2002
Posts: 893
Likes: 0
From: Liberal Kansas
Re: Perplexed - Coolant disappearing (SurfnSun)
When you made the statement about still having pressure even though the car sat all not makes me think that it could be head gasket. Like I said before I have not had this problem with the vette but on my RR the head gasket leak was letting the combustion gases pressurize the cooling system. Just a thought. You would think a leak big enough to drop a quart every 2 days would show up in the oil. It could be that the coolant is going into the combustion chamber and becauseits winter you dont notice the extra steam coming off the exhaust and when it gets up to operating temp the cats burn off the coolant before it gets out the exhaust
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Burning Brakes
Joined: Jul 2002
Posts: 1,050
Likes: 59
From: McLean Va
Re: Perplexed - Coolant disappearing (jimswhite92)
Although mine is ZR-1 and not an LT1, when I had a similar coolant loss, it was small crack on the plastic portion of the radiator and seepage at the seam between the plastic portion and the aluminum portion of the radiator. It did not give off visible steam bur rather seeped out. Get a good flash light and check these seams best you can, front and back.
Good luck. :seeya
Good luck. :seeya
Thread Starter
Racer
Joined: Jan 2003
Posts: 321
Likes: 0
From: Birmingham AL
Re: Perplexed - Coolant disappearing (chucks88)
I'm not sure. Is this a possibility ???? What should I look for????
If it is a head gasket, how can I check in advance. Is changing a head gasket a major job for the novice that I am ???? :confused: :confused: :confused:
Thx .. Jim
If it is a head gasket, how can I check in advance. Is changing a head gasket a major job for the novice that I am ???? :confused: :confused: :confused:
Thx .. Jim
Burning Brakes
Joined: Jan 2002
Posts: 893
Likes: 0
From: Liberal Kansas
Re: Perplexed - Coolant disappearing (jimswhite92)
Leak down test on Cylinders, Chucks88 has a good point. In my case I had no coolant on my plugs. Could be a crazy British thing in my case. Also some shops have a maghine that can sniff you coolant system for combustion gases. Check out this link also.
http://forums.corvetteforum.com/zero...=299208&page=1
[Modified by Rob90, 7:38 PM 1/25/2003]
http://forums.corvetteforum.com/zero...=299208&page=1
[Modified by Rob90, 7:38 PM 1/25/2003]
Drifting
Joined: Jan 2002
Posts: 1,663
Likes: 139
From: Vail AZ
Re: Perplexed - Coolant disappearing (jimswhite92)
Jim,
Did it leak BEFORE you changed the thermostat? If not, start there. I had a similar problem many years ago after changing a thermostat. Coolant was seeping up the threads in one of the bolts holding the thermostat housing on. It was enough to lower the coolant level after a day or so, but not enough to drip from the engine. It just leaked out and evaporated off the hot engine. I ended up taking the bolts back out and coating them with Permatex flexible sealant and it never leaked again.
Tom
Did it leak BEFORE you changed the thermostat? If not, start there. I had a similar problem many years ago after changing a thermostat. Coolant was seeping up the threads in one of the bolts holding the thermostat housing on. It was enough to lower the coolant level after a day or so, but not enough to drip from the engine. It just leaked out and evaporated off the hot engine. I ended up taking the bolts back out and coating them with Permatex flexible sealant and it never leaked again.
Tom
Thread Starter
Racer
Joined: Jan 2003
Posts: 321
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From: Birmingham AL
Re: Perplexed - Coolant disappearing (tpiini)
Tom,
That may be a possibility. Although the coolant level has gone down in the past(I've only owned the car for two months) it has never gone down so fast as it is now. I also took off some hoses and flushed out the heater core. I'll check there also.
Daughter came home from college today so I can't work in the basement (she brought her dog.) Don't want to risk spilling any anti-freeze with a dog around. I'll check it out outside tomorrow and let you know.
Another question.... With the low coolant, how come the system is not drawing any coolant from the reservoir???
Thx again ... Jim
That may be a possibility. Although the coolant level has gone down in the past(I've only owned the car for two months) it has never gone down so fast as it is now. I also took off some hoses and flushed out the heater core. I'll check there also.
Daughter came home from college today so I can't work in the basement (she brought her dog.) Don't want to risk spilling any anti-freeze with a dog around. I'll check it out outside tomorrow and let you know.
Another question.... With the low coolant, how come the system is not drawing any coolant from the reservoir???
Thx again ... Jim
Safety Car
Joined: Feb 2002
Posts: 4,212
Likes: 10
From: Sun City West Az
Re: Perplexed - Coolant disappearing (jimswhite92)
Did you bleed the system ( You have 2 bleed screws on the 92) after changing the t-stat?..You can do a couple of things if your so inclined. Drive it to a service station and have them put a pressure tester on the surge tank and apply about 15 psi and start looking for leaks. If you don't find any leaks using the pressure tester, run a compression test on the cylinders.
They should be with in 10% of each other. If you find one that is out of spec, use some shop air, pull that plug , pipe the shop air into the cylinder via an adaptor, rotate the crank to the compression stroke and apply about 60 psi. If you get air bubbles coming out of the surge tank or around the head, you have found your problem..head gasket. It's a PIA but you will sve a bunch of $ and you will know where you stand.
[Modified by ittlfly, 7:32 PM 1/25/2003]
They should be with in 10% of each other. If you find one that is out of spec, use some shop air, pull that plug , pipe the shop air into the cylinder via an adaptor, rotate the crank to the compression stroke and apply about 60 psi. If you get air bubbles coming out of the surge tank or around the head, you have found your problem..head gasket. It's a PIA but you will sve a bunch of $ and you will know where you stand.
[Modified by ittlfly, 7:32 PM 1/25/2003]
Drifting
Joined: Jan 2002
Posts: 1,663
Likes: 139
From: Vail AZ
Re: Perplexed - Coolant disappearing (jimswhite92)
The engine will draw coolant from the reservoir only when it cools down. The vacuum caused by the cooling pulls it in. BUT... if you have a leak somewhere in the system, the vacuum necessary to pull air into the leak will usually be less than the vacuum necessary to pull coolant in from the reservoir. Thus, the vacuum is nullified by the path of least resistance.
Tom
Tom
Racer
Joined: Aug 2002
Posts: 259
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From: Chicago Suburb Illinois
Re: Perplexed - Coolant disappearing (jimswhite92)
Jim it's been a long time since i did this, but in diagnosing combustion in the cooling system i used to disconnect the fan belt off the water pump and run the engine. If combustion is present you will see bubbles in the radiator.
Good luck...... Mike......... :cheers:
Good luck...... Mike......... :cheers:
Team Owner
Joined: Aug 1999
Posts: 24,017
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St. Jude Donor '10
Re: Perplexed - Coolant disappearing (Mike_D)
Jim it's been a long time since i did this, but in diagnosing combustion in the cooling system i used to disconnect the fan belt off the water pump and run the engine. If combustion is present you will see bubbles in the radiator.
Good luck...... Mike......... :cheers:
Good luck...... Mike......... :cheers:
Thread Starter
Racer
Joined: Jan 2003
Posts: 321
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From: Birmingham AL
Re: Perplexed - Coolant disappearing (ittlfly)
I've heard the 92 has two bleed screws. Sinced I do not have any manuals yet (They're on order) I can only locate the one on the neck above the thermostat.
Where is the other bleed screw ????
Thx ... Jim
Where is the other bleed screw ????
Thx ... Jim
Drifting
Joined: Aug 2000
Posts: 1,251
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Re: Perplexed - Coolant disappearing (jimswhite92)
The bleeder screw is just to get an air bubble out of it. An air lock or bubble will not cause the engine to lose fluid.
If your smelling it in the exhaust then you should see alot of white smoke.
My bet is head gasket.
If your smelling it in the exhaust then you should see alot of white smoke.
My bet is head gasket.