LS1 Overheating.. Bad Tstat?
Thread Starter
Teching In
Joined: Aug 2016
Posts: 18
Likes: 0
From: Toronto
LS1 Overheating.. Bad Tstat? recently replaced my water pump, took it out for a drive no problems, the next day went out for another drive, later that day as i was pulling in the temp gauge started rising and coolant was leaking fast. wasn't coming from the gaskets or weep hole, it looked like it was coming from one of the heater or rad hoses i couldn't tell which but right above them the inside of the hood was sprayed and the area around. i checked the hoses and clamps, there are no issues with them at least large enough for that much coolant to leak so quickly.
Now, once the car gets up to temp it begins to overheat and the leak starts again. it looks like it is coming from the lower rad hose, could it be that my tstat is shot? not opening and the coolant is building up in the hose and spraying out?
Also, i filled the coolant back up, and the dip stick in the reservoir level has not changed at all whether the engine is hot or cold.
any ideas will help, thanks
Now, once the car gets up to temp it begins to overheat and the leak starts again. it looks like it is coming from the lower rad hose, could it be that my tstat is shot? not opening and the coolant is building up in the hose and spraying out?
Also, i filled the coolant back up, and the dip stick in the reservoir level has not changed at all whether the engine is hot or cold.
any ideas will help, thanks
Last edited by DeadlyWS6; Mar 28, 2017 at 12:13 AM.
On The Tree
Joined: Jul 2015
Posts: 100
Likes: 3
From: Toronto
maybe it is the thermostat
If the car is overheating and you have put the new waterpump in properly with all gaskets and tightened down properly, its most likely the tstat being stuck.
If it is stuck the fluid wont be able to travel into the coolant jacks causing it to over flow and maybe start to leak ?
there is a quiet a few ways to check if it is stuck, when the engine gets warm feel the upper n lower hoses if they are cold.
you can also take the thermostat out and put it into boiling water to see if opens up...
I am not 100% its your tsat just giving you a trial and error..
any one else on the forum that my know what it is? correct me if I am wrong
If the car is overheating and you have put the new waterpump in properly with all gaskets and tightened down properly, its most likely the tstat being stuck.
If it is stuck the fluid wont be able to travel into the coolant jacks causing it to over flow and maybe start to leak ?
there is a quiet a few ways to check if it is stuck, when the engine gets warm feel the upper n lower hoses if they are cold.
you can also take the thermostat out and put it into boiling water to see if opens up...
I am not 100% its your tsat just giving you a trial and error..
any one else on the forum that my know what it is? correct me if I am wrong
TECH Addict
Joined: Oct 2016
Posts: 2,513
Likes: 480
From: PDX-OR-USA
Air in the system, a wetting agent will help the air bleed out.
If a hose is leaking did you make sure the clamp is past the lump around where it clamps on?
Torqued bolts correctly? Chased threads? (I always do that on aluminum parts.. Just me... )
If a hose is leaking did you make sure the clamp is past the lump around where it clamps on?
Torqued bolts correctly? Chased threads? (I always do that on aluminum parts.. Just me... )
TECH Addict
Joined: Aug 2005
Posts: 2,305
Likes: 126
From: Monroe,NY
Fill the motor through the top radiator hose. Then connect hose and top off the radiator. Everytime i do it this way i always get all the air out right away. Then once the thermostat opens check level.
I agree sounds like you got air trapped in the system.Jacking the car up in the front might help with getting the air to the top of the radiator. If you have access to a cooling system funnel that goes on the radiator that would help out a lot. Good luck, Kevin
Thread Starter
Teching In
Joined: Aug 2016
Posts: 18
Likes: 0
From: Toronto
Thanks, Sounds good lll get that done, no longer leaks but it does overheat once at temp. There was white smoke and smelled sweet coming from the exhaust but I'm guessing whatever was in the block burned out because it's not happening anymore, thought I had a blown head gasket. I will do a complete drain and bleed of the coolant system and see if that cures the overheating issue. Thanks everyone
Trending Topics
Thread Starter
Teching In
Joined: Aug 2016
Posts: 18
Likes: 0
From: Toronto
After a flush and bleed the car is still overheating! if anyone can think of anything else as to why it would still be overheating please let me know, i really hope it isn't a head gasket.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Sounds like you have a blown head gasket. Pull your plugs until you find the 1 or 2 that look different from the rest. At that point you can also run a compression check if the plugs don't show anything.
TECH Apprentice
Joined: Jul 2008
Posts: 309
Likes: 1
Clean it Pull your radiator out and run a hose through the fins to clean all the gunk out. These cars have been around long enough to get a bunch of crap stuck in the radiator fins.
While the radiator is out clean your condenser as well.
While the radiator is out clean your condenser as well.
^^^ Lousy core thickness and obstructed airflow
are way more likely than a thermostat failure. Though
you might also check that the little bubble-bleed thing
is free moving, and then "burp the baby".
Bad head gasket doesn't need the motor to be hot,
to start puking. Only needs high cylinder pressure.
And even then, coolant ought to come out the
overflow, past the radiator cap, not a hose or at
the block. But sweet white smoke, bad. If it keeps
up.
If the system can't hold pressure it will boil, perhaps
locally below the thermostat crackpoint (heads are
always hotter than coolant)..
are way more likely than a thermostat failure. Though
you might also check that the little bubble-bleed thing
is free moving, and then "burp the baby".
Bad head gasket doesn't need the motor to be hot,
to start puking. Only needs high cylinder pressure.
And even then, coolant ought to come out the
overflow, past the radiator cap, not a hose or at
the block. But sweet white smoke, bad. If it keeps
up.
If the system can't hold pressure it will boil, perhaps
locally below the thermostat crackpoint (heads are
always hotter than coolant)..
Rent a cooling system pressure tester and domestic radiator cap adapter from your local auto parts store
It's basically a hand pump that goes in your radiator. Pump up the tester to 15psi and look for any coolant leaks.
A bad thermostat wouldn't cause a coolant leak. Find the leaks with the tester, fixing the leaks will fix your problems
It's basically a hand pump that goes in your radiator. Pump up the tester to 15psi and look for any coolant leaks.
A bad thermostat wouldn't cause a coolant leak. Find the leaks with the tester, fixing the leaks will fix your problems