Leak
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Senior User
Joined: Sep 2003
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From: Jersey
Leak
I have been losing coolant slowly but can't seem to pinpoint where. At first I saw a little accumulation underneath the thermostat, so I changed the thermostat and gasket, tighted both hoses. Now there is no puddle but the coolant is still disappearing somewhere. There is no other visible leakage. What are some common areas and where should I be looking.
Lead Driver
Joined: Sep 2002
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From: Gateway to the West
You may be dealing with a pressure leak in which case it will only leak when the system is hot and under pressure. If its in the right spot, the coolant that leaks never hits the ground it just hits something hot in the engine compartment and evaporates. Check it before you shut it down after you get home some evening. Hoses are notorious for weakening near their clamps and having this type of leak. Check for wet spots on the radiator as well. Sometimes radiators can get pinhole leaks that will act the same way (only under pressure). If its none of this, give the exhaust a sniff and see if its smelling "sweet". This would be worst case scenario and probably means a head gasket problem allowing coolant into the combustion chamber(s). Good luck, let us know what you discover.
Something I just remembered...Several people here have had a problem with the lower intake coolant crossover passages leaking at the intake-to-cylinder head gaskets. At the front and rear of every 302 & 351 the lower intake has a coolant passage that runs from one cylinder head to the other. Sometimes they leak to the outside of the engine but occasionally they leak internally which lets coolant into an intake port adjacent to the coolant passage.
Something I just remembered...Several people here have had a problem with the lower intake coolant crossover passages leaking at the intake-to-cylinder head gaskets. At the front and rear of every 302 & 351 the lower intake has a coolant passage that runs from one cylinder head to the other. Sometimes they leak to the outside of the engine but occasionally they leak internally which lets coolant into an intake port adjacent to the coolant passage.
Last edited by greystreak92; Oct 21, 2003 at 04:35 PM.
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From: Independence, MO
do you have a recovery tank? make shure it not leaking, if you cant find any leaks anywhere then check your crank case (oil) see if you have coolant in the motor oil, you may want to do a system presure test, do you get any steam from your exhaust? which would be an idication of a bad head gasket, cracked water jacket, you may not leak into the oil instead it may leak in the cylinder and burn it. I'm shure some will jump in with something i've missed but that all i can think of for the moment, oh one other thing do smell coolant in the vehicle?, may be heater core leaking in the pasenger floor board. hope this helps. DW
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Joined: Sep 2003
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From: Roseville
I had this problem last summer in my '90 turned out to be exactly what greystreak said. It was a pressure leak. took it over to my buddy's shop and hooked it up to a pressure system and then pumped it up. sure enough, a one of the little hose was peeing under pressure. if you don't have access to a pressure system to test, I would recommend replacing all the hoses at once so you only have the drain the radiator once, otherwise, chances are, you'll replace what you think it is and then you'll find another one and have to start over again (been there done that). good luck
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From: Jersey
thanks guys...unfortunately I won't be able to check till the weekend
I'm hoping it's a pressure leak...I will change all my hoses and check everything you guys suggested this weekend...hopefully that will solve my problem. But what would the worse case scenario be money wise? There is no smell in the cabin but there is steam coming from the exhaust. It is cold here now though and I haven't had a chance to check if it's continuous. Sniffed it breifly at start up and doesn't seem to be sweet...but what does a sweet exhaust smell like?
Thanks again guys, I'll keep you posted.
Thanks again guys, I'll keep you posted.
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Joined: Oct 2003
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From: Greensburg, PA
I had a small leak also, and found it to be the heater core. I couldn't find the missing fluid, and there was no puddle on the floor of the truck. The reason... The hole in the heater core was just small enough to leak, and then burn off and make some green/white powder that just sat in the bottom of the heater box. It's pretty cheap, and easy to get at to check.
If you decide to check it, make sure that the box seals tight (some new sealant would be a good idea) or you'll have a flood if the new one fails.
If you decide to check it, make sure that the box seals tight (some new sealant would be a good idea) or you'll have a flood if the new one fails.
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Joined: Sep 2002
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From: Gateway to the West
stupato,
Burning coolant is unmistakable. It smells like it would if you were leaking it through the tailpipe. Remember, plain water is a natural by-product of the internal combustion cycle so early morning or "first-run" moisture from the tailpipe doesn't necessarily mean thats the problem.
In the event you are dealing with coolant in a combustion chamber, you will either be dealing with a head gasket and/or a lower intake-to-cylinder head gasket. The dollars to repair depend greatly on how much or how far you are willing to go to repair it yourself. Either is a pricey job for a shop.
Honestly, I'd make certain its not a hose or other pressure leak first. You can hunt down the coolant in a combustion chamber by pulling the spark plugs and checking them. Enough of it in a cylinder and it will foul the plug. Like DW said, change the oil and check for coolant in the oil too. Failed head gaskets can let coolant into the crankcase but not necessarily into the cylinders. Coolant will appear as streaks or globs of brown/grey milky looking crud in the oil. Its heavier and tends to settle into low spots so if its there it should appear in the oil from the pan.
Good luck, let us know what you discover.
Burning coolant is unmistakable. It smells like it would if you were leaking it through the tailpipe. Remember, plain water is a natural by-product of the internal combustion cycle so early morning or "first-run" moisture from the tailpipe doesn't necessarily mean thats the problem.
In the event you are dealing with coolant in a combustion chamber, you will either be dealing with a head gasket and/or a lower intake-to-cylinder head gasket. The dollars to repair depend greatly on how much or how far you are willing to go to repair it yourself. Either is a pricey job for a shop.
Honestly, I'd make certain its not a hose or other pressure leak first. You can hunt down the coolant in a combustion chamber by pulling the spark plugs and checking them. Enough of it in a cylinder and it will foul the plug. Like DW said, change the oil and check for coolant in the oil too. Failed head gaskets can let coolant into the crankcase but not necessarily into the cylinders. Coolant will appear as streaks or globs of brown/grey milky looking crud in the oil. Its heavier and tends to settle into low spots so if its there it should appear in the oil from the pan.
Good luck, let us know what you discover.
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Joined: Mar 2003
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From: Warren, MI
Originally posted by DW2455
do you have a recovery tank? make shure it not leaking, if you cant find any leaks anywhere then check your crank case (oil) see if you have coolant in the motor oil, you may want to do a system presure test, do you get any steam from your exhaust? which would be an idication of a bad head gasket, cracked water jacket, you may not leak into the oil instead it may leak in the cylinder and burn it. I'm shure some will jump in with something i've missed but that all i can think of for the moment, oh one other thing do smell coolant in the vehicle?, may be heater core leaking in the pasenger floor board. hope this helps. DW
do you have a recovery tank? make shure it not leaking, if you cant find any leaks anywhere then check your crank case (oil) see if you have coolant in the motor oil, you may want to do a system presure test, do you get any steam from your exhaust? which would be an idication of a bad head gasket, cracked water jacket, you may not leak into the oil instead it may leak in the cylinder and burn it. I'm shure some will jump in with something i've missed but that all i can think of for the moment, oh one other thing do smell coolant in the vehicle?, may be heater core leaking in the pasenger floor board. hope this helps. DW
If it steams in the winter only is that ok? I have always thought about it like when i breath hot air out of my mouth, its the same with my car right?
Adam
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From: Independence, MO
Originally posted by AYoungblood
Dumb question:
If it steams in the winter only is that ok? I have always thought about it like when i breath hot air out of my mouth, its the same with my car right?
Adam
Dumb question:
If it steams in the winter only is that ok? I have always thought about it like when i breath hot air out of my mouth, its the same with my car right?
Adam
then yup i quess you would think it a dumb question. but either way i guess you said it right, it just hot air coming out of your mouth. DW
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Joined: May 2003
Posts: 28
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From: Ottawa
The other spot to look at is the timing chain cover. Mine developed a pinhole in the inner gasket surface where the casting wasn't perfect. If it's underneath, the coolant runs down the block and evaporates. If it's on top, you will usually see a puddle in the timing chain cover.
