Cooling question. Help please
Thread Starter
8th Gear
Joined: Feb 2017
Posts: 8
Likes: 0
From: Aiken SC
Cooling question. Help please
1998 6 speed Stock except Borla Exhaust.
I have searched and read until I am completely confused.
I bought my C5 in febuary of this year. Until now the car has driven like a champ. I haven't hit anything or even driven harder than the occasional spirited driving.
I started the car the other day and it said low coolant. I have never noticed any leaking or puddles. I ended up adding almost a gallon of coolant?
I went for a short drive and when I stopped I noticed coolant dripping from my Right side behind the tire so I went straight home and parked to let the car idle and try to find the leak. It did not overheat.
I noticed the coolant was leaking from the reservoir cap so I bought a new one. I went for a nice long spirited drive after replacing the cap and the temp gauge never went above halfway.
UNTIL I got to my neighborhood and started driving slow.
THEN the temp gauge started rising so I immediately parked. I didn't let it overheat.
I popped the hood and coolant was POURING from the new cap and it was boiling.
I let the car cool off and cranked and let it idle until it did the exact same thing. I don't understand why. The fans are coming on. It seems like it was fine until I am stopped.
Has anyone had this problem? or does anyone know what could cause this?
Thanks
I have searched and read until I am completely confused.
I bought my C5 in febuary of this year. Until now the car has driven like a champ. I haven't hit anything or even driven harder than the occasional spirited driving.
I started the car the other day and it said low coolant. I have never noticed any leaking or puddles. I ended up adding almost a gallon of coolant?
I went for a short drive and when I stopped I noticed coolant dripping from my Right side behind the tire so I went straight home and parked to let the car idle and try to find the leak. It did not overheat.
I noticed the coolant was leaking from the reservoir cap so I bought a new one. I went for a nice long spirited drive after replacing the cap and the temp gauge never went above halfway.
UNTIL I got to my neighborhood and started driving slow.
THEN the temp gauge started rising so I immediately parked. I didn't let it overheat.
I popped the hood and coolant was POURING from the new cap and it was boiling.
I let the car cool off and cranked and let it idle until it did the exact same thing. I don't understand why. The fans are coming on. It seems like it was fine until I am stopped.
Has anyone had this problem? or does anyone know what could cause this?
Thanks
Last edited by Jerimy; Sep 29, 2017 at 08:41 PM.
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sounds like you probably have an air pocket somewhere in the system... what I always do is leave the coolant reservoir cap off and fill it to the proper level then start the car and just let it idle... you can massage the radiator hoses as it warms up to help burp out any air that may be trapped inside of them and just let it continue to run until your fans cycle on and off a few times, add coolant to the reservoir if needed during the process... once that is done replace the cap, drive it around for a little bit, then bring it home and let it cool off and after it's completely cooled off you can top off the reservoir if needed... I don't follow the gospel in the fsm but this method has always worked great for me
Thread Starter
8th Gear
Joined: Feb 2017
Posts: 8
Likes: 0
From: Aiken SC
sounds like you probably have an air pocket somewhere in the system... what I always do is leave the coolant reservoir cap off and fill it to the proper level then start the car and just let it idle... you can massage the radiator hoses as it warms up to help burp out any air that may be trapped inside of them and just let it continue to run until your fans cycle on and off a few times, add coolant to the reservoir if needed during the process... once that is done replace the cap, drive it around for a little bit, then bring it home and let it cool off and after it's completely cooled off you can top off the reservoir if needed... I don't follow the gospel in the fsm but this method has always worked great for me
After that is when I took it for the drive and it heated and overflowed when I parked in the garage.
I bought a new thermostat and plan on installing it this weekend and I'll try the process that you described again when I do.
Is there anything else that could cause a buildup of pressure enough to boil and make it push through the cap?
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2020 Corvette of the Year Finalist (performance mods)
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how long did you let it sit and run at idle with the cap off?... some air pockets are stubborn and I usually let it run for a good 20-30 mins before I call it good
Thread Starter
8th Gear
Joined: Feb 2017
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From: Aiken SC
I tried it again after the car cooled down with the cap off just like you said and it started boiling, then coolant eventually blew out all over the place.
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2020 Corvette of the Year Finalist (performance mods)
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is one of the hoses considerably cooler than the other when the coolant boils?... it's possible the thermostat is stuck like you suspected
Last edited by StingrayRebel; Sep 29, 2017 at 11:52 PM.
Racer
Joined: May 2005
Posts: 283
Likes: 16
Pull the Thermostat and test it, or just replace it, this is a <$20 fix if you do it yourself.
You may also want to look up the burping procedures and consider pulling the cross over tube as explained in the service manual and in several posts.
Good luck. Lets get that car back on the road
Melting Slicks
Joined: Feb 2014
Posts: 2,725
Likes: 149
From: chicago area IL.
when we swapped my sons pickup over to LS base engine burping the coolant system was a pain seriously! we jacked up the truck high in the front to vent the crossover tube until coolant was coming out still did do it, massaged the hoses still nothing no flow or any thing i got so aggravated i sucked on the top radiator hose until it started to flow that was the only way i was able to get the air out of the system
btw coolant taste horrable
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Le Mans Master
Joined: May 2006
Posts: 5,747
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From: Hillsboro Oregon
Google is your friend sometimes.
The burping process is pretty easy and well documented
https://www.google.com/search?q=burp...hrome&ie=UTF-8
The burping process is pretty easy and well documented
https://www.google.com/search?q=burp...hrome&ie=UTF-8
Thread Starter
8th Gear
Joined: Feb 2017
Posts: 8
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From: Aiken SC
OK so I installed the new thermostat today.
I tried the crossover tube process but It never ran out.
So I did the burping procedure as explained..
Seems as if it was the thermostat that was causing the problem. I'm assuming that is what it was considering I burped the system before installing the new thermostat and still had the same problems.
I drove around a LOT today after installing the thermostat, and burping. Open road and around town at slower speeds.
I even hit a long wait drive through and also let the car sit and idle in the garage afterwards. No overflow or boiling.
When sitting temps reached higher, temps ran around 210-220 (approximate) and cruising temps were between 190- 196 (approximate).
** For anyone else with the same problems I would recommend a new thermostat and reservoir cap and proper burping process first.
Note- My temp ranges are approximate.
Thank you all for the advice.
Ill update if anything changes.
I tried the crossover tube process but It never ran out.
So I did the burping procedure as explained..
Seems as if it was the thermostat that was causing the problem. I'm assuming that is what it was considering I burped the system before installing the new thermostat and still had the same problems.
I drove around a LOT today after installing the thermostat, and burping. Open road and around town at slower speeds.
I even hit a long wait drive through and also let the car sit and idle in the garage afterwards. No overflow or boiling.
When sitting temps reached higher, temps ran around 210-220 (approximate) and cruising temps were between 190- 196 (approximate).
** For anyone else with the same problems I would recommend a new thermostat and reservoir cap and proper burping process first.
Note- My temp ranges are approximate.
Thank you all for the advice.
Ill update if anything changes.
Last edited by Jerimy; Oct 1, 2017 at 10:03 PM. Reason: additional info
Le Mans Master
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From: Ft. Lauderdale Fl
Tech Contributor
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From: Charlotte, NC (formerly Endicott, NY)
When a C5 is overheating it also is a good idea to make sure the cooling air flow isn't obstructed by debris stuck in the AC Condenser. It starts lodging in the Condenser at the top and works it's way down from there.
Another thing to check are the foam insulators between the AC Condenser and the radiator shroud. They tend to deteriorate quickly and blow out into the engine compartment beside the condenser. You can check to see if they are blown out by opening the hood and looking at the forward section of the engine compartment next to where the Condenser is located. If you see some black stringy things sticking into that area the seals are more than likely blown out. When they are blown out that permits air coming in from the bottom of the car to flow into the engine compartment without going through the Condenser or the Radiator.
Bill
Another thing to check are the foam insulators between the AC Condenser and the radiator shroud. They tend to deteriorate quickly and blow out into the engine compartment beside the condenser. You can check to see if they are blown out by opening the hood and looking at the forward section of the engine compartment next to where the Condenser is located. If you see some black stringy things sticking into that area the seals are more than likely blown out. When they are blown out that permits air coming in from the bottom of the car to flow into the engine compartment without going through the Condenser or the Radiator.
Bill