C5 / LS1 high coolant temp.
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Joined: Nov 2007
Posts: 60
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From: Florida
C5 / LS1 high coolant temp.
For the past month I’ve noticed that my 2000’ C5 will jump in coolant temp up to 230º (note the red line is 260º) when ever the car is at low speed, traffic jam or stop light? When going over 40mph it will cool down to a more normal 200º (the temp its stayed at for the past 6 years summer or winter). The fan does not seem to kick on as often as it used to but it will work after a while? I am seeing no signs of belt slip on the water pump. I’m sure I’m due for a coolant change.
The temp vs speed deal could mean the +40mph air is pulling heat out of the radiator or the higher RPM is processing more coolant thru the radiator?
Has any one else experienced this issue? Any web links?
Thanks,
SG
The temp vs speed deal could mean the +40mph air is pulling heat out of the radiator or the higher RPM is processing more coolant thru the radiator?
Has any one else experienced this issue? Any web links?
Thanks,
SG
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
As mentioned already, look for debris plugging the air path through the condensor to the radiator. Also turn on the HVAC and verify that the fans are operating.
Pro
Joined: Aug 2010
Posts: 593
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From: San Antonio Texas
I checked mine and was amazed at the amount of junk I pulled out. A handfull of pine needles, a plastic bag, a paper cup, and some sticks were wedged up in there. The Vette is a bottom feeder for air so it is important to check this regularly!!
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Joined: Nov 2007
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From: Florida
There where some leaves and twigs on the radiator, I cleaned them out I would guess 20% blockage from this in total. I also see a foam rubber seal that’s popped out of place when I look up in there so ill need to look at that. The coolant level was on the low side so I added some 50/50 dex cool. The fans do run, I just remember them turning on and off more often, I need to do the A/C fan check. The car has never gotten past the half way mark on the temp gauge before last month from what I can remember it seems like something new.
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Tech Contributor
Joined: Dec 2006
Posts: 10,962
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From: Van Buren Arkansas
Wounded Warrior Escort '11
Its when you notice something different is exactly when you need to pay attention and figure out what's going on rather than ignoring. 10 points for you! Check for leaks, even small ones. Do you smell any coolant? When you first shut it down after a full heat up, check the upper radiator hose and see if it stays pressurized for a short while. Coolant can start leaking from the water pump weep hole and its hard to detect if its only a small amount but indicative of a pending issue coming. Also the surge tank is a pressurized tank and the nipple line from it will crack at the joint of the nipple to the tank. In my case, I could smell coolant but couldn't find it and the system was not staying pressurized. I eventually found a hairline crack at the top left of the radiator.
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Joined: Nov 2007
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From: Florida
When I pulled the car into the garage I noticed a big puddle of coolant on the drive way, then when I opened the hood I noticed that the tank was low again and there was a lot of coolant staining under it. I dug into it more tonight and on the “T” fitting on the bottom of the tank there is some coolant staining on the aft hose. What is the best way to fix this? Hole new hose? Clean up and RTV? O ring? I removed the tank but left the hoses on, every thing I can see on the tank looks fine. Is there some sort of pressure relief or did it just find the weakest point and start draining the tank from there?
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
The tank is plastic obviously and will get brittle over time and with the engine heat. I would suggest just go ahead and replace it. They are not expensive.
Melting Slicks
Joined: Mar 2008
Posts: 2,453
Likes: 347
From: SC
I just had a similar issue. My leak was coming from a hose on the bottom nipple. I replaced the GM hose clamps with worm clamps. Leak problem solved. Apparently, those original clamps can fail, especially if they have been removed and replaced. The tank held pressure, no leaks there.
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Joined: Jun 2007
Posts: 94
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From: PA
I suggest buying a new tank. A previous owner did the worm clamp on the cracked nipple very poorly and when I drove the car home for the first time the nipple broke completely off and lost pressure and coolant. The temp spiked quickly and the DIC dinged and I pulled over right away. We mended it, added coolant back in and made the rest of the 40 miles that way. I'm waiting for a new tank so i don't have to worry about it. So my first ride was interesting in more ways than one. Oh and all I can smell now is coolant. The hood liner is soaked with it. DOH!
