Car started overheating
Thread Starter
12 Second Club
Joined: Aug 2005
Posts: 62
Likes: 0
From: Tucson AZ.
Car started overheating I have a 99 Z28. I noticed last night when I came home the fan was still running when I shut it of. I've driven it at 90+ degress a couple days ago with no problems. Then tonight the gauge went right between the mark after 210 and 260 on they home. I noticed that the drivers side fan isn't on. What do I need to check?
On The Tree
Joined: Aug 2002
Posts: 150
Likes: 0
From: Vacaville, CA
cooling. I had the exact problem, and from what I have read. I would definitely go with the thermostat first. You will hear all sorts of things about 'air in the cooling system', and such. But I have come to the conclusion that the t-stat is definitely the most likely culprit. As for the lower degree t-stat. I dont see the big advantage. LS-1's like it hot and if you cool it off too much then your defeating the purpose. 180 degrees vs the stock 195 degrees might be a good idea. You can also have your car tuned to turn the fans on earlier than normal too. 2 cents.
How hot is yours getting? Do you get an idiot light? How's your temp above 40mph?
I have mixed feelings
about the lower temp stats. I replaced mine with a 180° one because I figured cooler is better. It regulates at 180° very nicely at 40+ MPH. In stop and go it climbs to 220-230°. I think whats happening is that the coolant does not have enough time to cool off in the radiator before it goes back into the engine because the flow is too high and the fans aren't powerful enough to simulate 40+mph air. I figure if I replace the stat with 195°, the coolant should spend more time in the radiator and maybe be at a more regulated temperature. Any body else have any thoughts on this?
It can't be good to temp cycle the engine like that.
I have mixed feelings
about the lower temp stats. I replaced mine with a 180° one because I figured cooler is better. It regulates at 180° very nicely at 40+ MPH. In stop and go it climbs to 220-230°. I think whats happening is that the coolant does not have enough time to cool off in the radiator before it goes back into the engine because the flow is too high and the fans aren't powerful enough to simulate 40+mph air. I figure if I replace the stat with 195°, the coolant should spend more time in the radiator and maybe be at a more regulated temperature. Any body else have any thoughts on this? It can't be good to temp cycle the engine like that.
Thread Starter
12 Second Club
Joined: Aug 2005
Posts: 62
Likes: 0
From: Tucson AZ.
The gauge was reading about 250 my guess when I shut it off. It just got hot two days ago. coolant level is good and both fans work. The only thing I could figure that could go bad that fast was the t-stat.
I would go ahead and get a new thermostat or at least pull yours out and check it. Your car is doing the same thing mine was doing awhile back. My problem was a sticky thermostat. From what I have heard and from personal experience, the water pumps on these cars hold up pretty well so I can't imagine that being the problem. You said the fans work so that's good, but it is six years old so it may need a radiator flush. I've had a few friends need to replace thermostats that went bad prematurely on these just like I had to, so I wouldn't count that idea out. Good luck.
Trending Topics
My 99 M6 Vert WS6 just started overheating about a week ago. Fans and coolant level checked out fine. I noticed one day that the temperature gauge was erratic and that I could significantly reduce the engine temperature by turning the heater on full. I assume (dangerously) that the coolant going through the heater does NOT have to go through the thermostat and hence I was using the heater as a secondary radiator. I bought a new stock thermostat at O'Reillys for $19.99 along with a new serpentine belt and installed them both. A close examination of the old thermostat did not indicate any problems and both it and the coolant were remarkably clean. I was not confident that I had found the problem, but when I took the car out into 100+ degree heat, the temp gauge stayed exactly where it had been before the problem started. Needle straight up (about 210 degrees I think). I was one happy camper! 
Tom
Tom
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
Mine overheated on the way home from picking it up and when i turn the car off now i can hear the coolant boiling (just now i did and the temp gauge was right at 210). I am changing the thermostat later and having the cooling system flushed. Have any of you had this problem (hearing it boiling but it not boiling out)? It had a little coming out when i parked it now but not even enough to drop onto the ground (out of the resevoir fill).
Any help would be appreciated.
William
Any help would be appreciated.
William
When was the last time you checked your coolant for level and mix?
If the temp gauge is accurate, it sounds like you don't have a 50/50 mix of coolant and water. You probably have a lot more water than coolant. Or, you could have air leaking into your system. If that happens, your coolant pressure drops along with the boiling point.
What do you mean when you say that you overheated and your temperature gauge is right at 210°? Do you mean that it overheated one time and now the water boils at 210°?
Water boils at 212°, so if you have 100% water, it may be just starting to boil and the reason why its not totally boiling over.
If the temp gauge is accurate, it sounds like you don't have a 50/50 mix of coolant and water. You probably have a lot more water than coolant. Or, you could have air leaking into your system. If that happens, your coolant pressure drops along with the boiling point.
What do you mean when you say that you overheated and your temperature gauge is right at 210°? Do you mean that it overheated one time and now the water boils at 210°?
Water boils at 212°, so if you have 100% water, it may be just starting to boil and the reason why its not totally boiling over.
I know what water boils at. I'm sure the mixture isn't exactly 50/50, but i'm getting the system flushed today. I was just saying, as soon as my temp gauge moves at all i need to pull over. It sits at 210 like i've heard everyone's does, but when it climbs even a hair above it just doesn't stop climbing so i just pull over before it gets above the line between 210 and 260. Then when i stop (temp gauge reading maybe 225-230) i hear the water boiling. Hopefully the 180 thermostat and new coolant solve the problem.
Its good that your flushing and refilling with new stuff if its boiling. The properties of the fluid that is currently in there has probably broken down from excessive heat and you probably have developed some air in your system from the overheating incident. If you are doing it yourself, make sure that you bleed the air out of the system or you will have the same problem. Good luck!
I'm taking it to a friends oil change place and getting the oil changed and the cooling system flush. Luckily i got a flat yesterday and damaged the tire so i'm getting a tire on there for now (cheapo matched set on back) then later i'll be getting 17x11's and maybe 315's on it...We'll see. I'll post up if the cooling problem persists.
William
William
Coolant is brand new. I think it's fixed now. I changed cap, thermostat (180), coolant flush, and it's working fine. It dropped a little fluid on the drive back to C.S. but i think it was a little overfull.
William
William
TECH Resident
Joined: Mar 2003
Posts: 754
Likes: 0
From: Texas...that says it all
Just a thought but you might want to get a pressure test done if starts to get hot, maybe it's the intake gasket..that's what happened to mine and thanks to someone here I got that taken care of...
mines been running the past few days really well (just under 210 is the hottest it sees) and that's letting it idle for 30 minutes or more in 100 degree temps with the a/c blasting.
I think it's fine now (knock on wood)
William
I think it's fine now (knock on wood)
William
