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Coolant Leak by randy86
Started on: 02-11-2020 02:35 PM
Replies: 14 (249 views)
Last post by: theogre on 03-19-2020 03:19 PM
randy86
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Report this Post02-11-2020 02:35 PM Click Here to See the Profile for randy86Click Here to Email randy86Send a Private Message to randy86Edit/Delete MessageReply w/QuoteDirect Link to This Post
I have a slow leak somewhere, I have to top off about once a week. Takes about a quart of coolant, but I cannot find the leak. I can smell coolant sometimes under hard acceleration and sometimes while idling for a while at a light. I have looked everywhere and cannot find a leak, the passenger floorboard is dry, no coolant on the ground.
Only think I can think of is a blown head gasket, but there is no smoke from the exhaust and the leak is not constant, meaning I can drive it for a day and coolant level stays the same.

Anyone have an idea?
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Gall757
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Report this Post02-11-2020 07:02 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
Yes!

This happens more often than you would expect. There is probably a puncture in a hose that only leaks when the system is up to pressure....so you are probably driving. Then sometimes the leak squirts coolant directly at something hot like an exhaust pipe...so there is no evidence. Pretty clever. Try laying out newspaper where you are going to park the car and put it on there nice and hot.
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theogre
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Report this Post02-11-2020 07:06 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
What Engine?

Look/feel the carpet in front of p-side.
Heater cores can leak then dump on floor. Plus you often smell coolant too when true.

That much coolant lose carpet should very wet and likely will need to remove seat etc to clean up.

Rad Cap or Tube for rad overflow can leak coolant when hot and/or suck air cooling off over night.

Iffy WP seal can leak and many cars is not easy to see when small leak.
Feel/look at WP Weep hole. Use mirrors if needed. Coolant even dry should show a clean(er) path when coolant washes the engine.

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randy86
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Report this Post02-11-2020 08:04 PM Click Here to See the Profile for randy86Click Here to Email randy86Send a Private Message to randy86Edit/Delete MessageReply w/QuoteDirect Link to This Post
It is a 2.8 and the carpet is dry. I will try both your suggestions and see what happens.

Thanks
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theogre
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Report this Post02-12-2020 03:16 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
Iffy hoses at clamps can leak under pressure too or when have bad engine/trans mounts the engine can pull on any clamp joints.
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DavidM
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Report this Post02-13-2020 12:12 AM Click Here to See the Profile for DavidMClick Here to visit DavidM's HomePageClick Here to Email DavidMSend a Private Message to DavidMEdit/Delete MessageReply w/QuoteDirect Link to This Post
I have a radiator pressure tester. Looks like a small bicycle pump and dozens of radiator cap fittings. Lets you put the 12lbs into the cooling system even when it is cold.
Much less dangerous way to find a leak that only occurs under pressure. I have seen it where a cylinder head leaked coolant into a cylinder ONLY when under the pressure of highway speed. The amount was so small there was no smoke. There was also a van I worked on where the head gasket again only leaked at highway load and displaced the coolant - We used a test kit that had colour changing liquid to find exhaust gases are in the coolant. Hope yours is just a pipe somewhere.
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AsaBergman
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Report this Post02-13-2020 10:33 AM Click Here to See the Profile for AsaBergmanClick Here to Email AsaBergmanSend a Private Message to AsaBergmanEdit/Delete MessageReply w/QuoteDirect Link to This Post
I had a mystery coolant leak that couldn't be pinned down as there was no coolant on the floor or car. I was losing coolant as vapor via the front radiator hoses and possibly a bad radiator tank. The only reason I found it was I pulled over one night on a test drive to check stuff and saw the vapor due to the headlights, it wasn't visible during the day. Replaced the coolant hoses and the radiator and I'm no longer losing coolant.
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randy86
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Report this Post03-11-2020 01:34 PM Click Here to See the Profile for randy86Click Here to Email randy86Send a Private Message to randy86Edit/Delete MessageReply w/QuoteDirect Link to This Post
Now I am really befuddled, car stopped leaking about 5 days after it started. I have not done anything, though I have not used the heater. So I think it is the heater core.

Thanks for all the help!

Randy
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Patrick
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Report this Post03-11-2020 02:34 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by randy86:

...though I have not used the heater. So I think it is the heater core.


How do you figure not using the heater is responsible for stopping the coolant leak? (...unless you've disconnected the coolant hoses and bypassed the heater core.)

[This message has been edited by Patrick (edited 03-11-2020).]

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randy86
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Report this Post03-11-2020 06:33 PM Click Here to See the Profile for randy86Click Here to Email randy86Send a Private Message to randy86Edit/Delete MessageReply w/QuoteDirect Link to This Post
Doesn't the Fiero have a valve to shutoff the coolant when the heater switch is set to cool.
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Patrick
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Report this Post03-11-2020 06:46 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by randy86:

Doesn't the Fiero have a valve to shutoff the coolant when the heater switch is set to cool.


Where'd you get that idea?

See a valve anywhere?

Non A/C heater core on the left..................... A/C heater core on the right.

[This message has been edited by Patrick (edited 03-11-2020).]

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randy86
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Report this Post03-19-2020 12:37 PM Click Here to See the Profile for randy86Click Here to Email randy86Send a Private Message to randy86Edit/Delete MessageReply w/QuoteDirect Link to This Post
Most cars have a switch to bypass flow to the heater when not needed and it is NOT on the heater core (geez) and I expected the fiero to have one too.
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fierosound
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Report this Post03-19-2020 12:44 PM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by randy86:

Most cars have a switch to bypass flow to the heater when not needed and it is NOT on the heater core (geez) and I expected the fiero to have one too.


Nope. Coolant runs through the heater core all the time.
The heater controls only direct air through the heater core, or around it.

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Patrick
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Report this Post03-19-2020 12:59 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by randy86:

Most cars have a switch to bypass flow to the heater when not needed and it is NOT on the heater core (geez) and I expected the fiero to have one too.


But... if you looked "everywhere", you would've seen the "switch" (if it existed). Not trying to give you a bad time, but you can't make any assumptions.

 
quote
Originally posted by randy86:

I have looked everywhere and cannot find a leak...

[This message has been edited by Patrick (edited 03-19-2020).]

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theogre
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Report this Post03-19-2020 03:19 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by randy86: corrections
Most cars have a switch valve to bypass flow to the heater when not needed and it is NOT on the heater core (geez) and I expected the fiero to have one too.
Some cars have heater bypass valves. Fiero and Most vehicles Never had this. Some cars Need the heater core hot even to run AC w/o evaporator freezing etc.

Even with a bypass valve the bad heater core will still leak coolant because often the core is still under pressure. Very common a valve Diverting Flow is Not = core sees No Pressure. Making a bypass killing Pressure to the core when bad would cost more to make.

The only way to bypass on most vehicles w/ bad core is remove both hoses and use tube to connect the ends.
Example:

This keeps both ends same size as heater core. Solder blobs keeps hoses on even if clamps get a bit loose and to make just get less heat and flux to prevent flow.
I made it 20+ years ago and posted before but can't find old img so just cleaned it for today pic to show easier.

Can use anything in a hurry but hose barbs etc have their own problems.
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