Low Coolant! - PLEASE Help

Dub

Dub

C5 Owner
Regular
2 You're 5
May 15, 2016
416
308
Lloydminster, SK.
VetteCoins
2,146
Car
1999 Magnetic Red C5
Province
SK
OK my car usually runs well under the 220 mark, in pretty much all driving conditions(unless getting on it hard) and last summer I recall the low coolant warning coming on once, and had to add a very small amount of coolant to the reservoir, and never had it happen again! Until Now!
So the wife and I were in Saskatoon this past weekend, specifically Friday, and the outside temp was hovering around the 31-32 degree Celsius mark, and while doing our regular river cruise, we were stuck in bumper to bumper traffic, due to the "Taste of Saskatchewan" festival that was going on, and we were unaware of!
Anyway, while moving at the speed of a physically challenged snail, my temp gauge climbed to the 230 F mark.:eek: In any other vehicle I've owned, this would've caused a small heart attack, but when investigating it on the "all reliable" WWW, this appears to be normal, or at least quite common.
Now when we got back home and let it cool off, I noticed the coolant was below the "COLD - FULL" mark a fair bit. I ended up having to add about a half liter to the reservoir, in order to get it back to full mark, and have been keeping a close eye on it, while driving around town and while its parked, and there are absolutely no leaks under the car!
Is this normal? Do I have a head gasket going possibly? Bad reservoir cap? Or am I just overthinking the whole thing?
Personally I prefer my engine to run as cool as possible, so if there's anything I can do, I'm open to doing whatever it takes to rectify the issue. Thanks in advance for any and all responses/help.
 
Sorry, I should have mentioned that we put on approx. 400-500 kms that day, and thinking about it more, I guess there could still be a leak somewhere, and I likely wouldn't have noticed that little bit of coolant(or steam at that point) releasing onto the ground or anywhere else for that matter.
 
You could try switching to a 160 degree thermostat. I was also told running the air conditioner will make the car run a little cooler. Wouldn't hurt to just change the coolant especially if it hasn't been changed in 5 years or longer.
 
It's doubtful you have a head gasket problem Dub. If the gasket is leaking past, you will both smell it and see white steam out the exhaust. I'm guessing you had the air conditioner on if it was 31-32 degrees. Running the air conditioner increases rotational loading to the engine and adding that to the fact that you were bumper to bumper and probably slow moving as well would have have been enough to drive up the temp. I'm betting if you could have hit the open road, you would have seen the temp drop fast....
 
henkz06 said:
You could try switching to a 160 degree thermostat. I was also told running the air conditioner will make the car run a little cooler. Wouldn't hurt to just change the coolant especially if it hasn't been changed in 5 years or longer.
Click to expand...
Actually I was thinking about changing the stat and see if that changes anything. I did flush the entire system last summer, and yes for some reason the car runs much cooler with the AC on(which really doesn't seem to make much sense to me, I would've thought it would run hotter), I actually leave it on all the time.
 
Black 03 Z06 said:
It is possible that it "puked" a little out. Refill it as you have and keep a close eye on it.

I do not think you have an issue, just got hot and when the coolant expands it has to go somewhere.
Click to expand...

Thanks! It may have puked some out, but like I said it was probably half a liter or less, so if it did release some fluid/steam, I likely wouldn't have noticed that small amount, but I will be keeping an eye on it! I hope it's just nothing, but time will tell.
 
Rruuff Day said:
It's doubtful you have a head gasket problem Dub. If the gasket is leaking past, you will both smell it and see white steam out the exhaust. I'm guessing you had the air conditioner on if it was 31-32 degrees. Running the air conditioner increases rotational loading to the engine and adding that to the fact that you were bumper to bumper and probably slow moving as well would have have been enough to drive up the temp. I'm betting if you could have hit the open road, you would have seen the temp drop fast....
Click to expand...

Thanks, I hope you're right about not having a head gasket issue, but as far as smell and the white exhaust smoke, I did pay close attention to the exhaust, but I'm doubtful that the small amount that I'm losing would be visible in the exhaust, but I maybe wrong? And yes I was certainly utilizing the a/c, but as henkz06 mentioned, these cars do run cooler with the a/c on, and when I turn it off, the temp really climbs quick.
I guess what I'm most concerned about is the 230-240 range that I was hitting that day, it kinda freaked me out? This is my first Vette, but if any of my many Mustangs that I've owned over the years, hit those kind of temps, I would have had it ripped apart by now. Is that not too high for these LS engines, or are they made to handle hi temps?
Sorry for all the questions.
 
Appears you and henkz are correct about turning the AC on to run cooler Dub... seems it starts the AC fan which helps cool.... From what I know, which isn't a lot, my next stab would be to have the rad and system flushed. Not sure how many km are on your C5 but they do tend to build up some gunk in the rad after a while. If nothing appears to be wrong and you still want to run cooler, there are several after market DIY fan controllers available. One being the Coolit from Sac City Corvettes.
 
Hi Dub. Head gasket problems don't always make smoke in the exhaust, sometime compression can leak in the cooling system because of a higher pressure in the combustion chamber than the pressure in the cooling system. When you run the a/c, your electric fan run almost all the time so it also cool you engine better. I never fixed much c5 but very often, dirt and road debris get stuck on the front of the condensor, I often have to remove the shroud and electric fan on cars and trucks to clean the radiator with a water hose and when possible move the radiator away and also clean the condensor. Make sure you spray the water from the engine bay in direction of the front bumper,(opposite way it came in), you will be amaze the amount of dirt you haved collect over the time.

Keep posting the result, good luck
Stephane
 
Rruuff Day said:
Appears you and henkz are correct about turning the AC on to run cooler Dub... seems it starts the AC fan which helps cool.... From what I know, which isn't a lot, my next stab would be to have the rad and system flushed. Not sure how many km are on your C5 but they do tend to build up some gunk in the rad after a while. If nothing appears to be wrong and you still want to run cooler, there are several after market DIY fan controllers available. One being the Coolit from Sac City Corvettes.
Click to expand...
Thanks, I appreciate all the input. I did just flush the system last year, but for no real reason, other than I felt it was time as the car has 120k on it now.
 
theboss said:
Hi Dub. Head gasket problems don't always make smoke in the exhaust, sometime compression can leak in the cooling system because of a higher pressure in the combustion chamber than the pressure in the cooling system. When you run the a/c, your electric fan run almost all the time so it also cool you engine better. I never fixed much c5 but very often, dirt and road debris get stuck on the front of the condensor, I often have to remove the shroud and electric fan on cars and trucks to clean the radiator with a water hose and when possible move the radiator away and also clean the condensor. Make sure you spray the water from the engine bay in direction of the front bumper,(opposite way it came in), you will be amaze the amount of dirt you haved collect over the time.

Keep posting the result, good luck
Stephane
Click to expand...

Thanks, and as for removing the entire rad.....If I do that, the same one will not be going back in. I will upgrade the rad and fans, if I'm going to go that far into it.
I'll keep you all posted.
 
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Dub said:
OK my car usually runs well under the 220 mark, in pretty much all driving conditions(unless getting on it hard) and last summer I recall the low coolant warning coming on once, and had to add a very small amount of coolant to the reservoir, and never had it happen again! Until Now!
So the wife and I were in Saskatoon this past weekend, specifically Friday, and the outside temp was hovering around the 31-32 degree Celsius mark, and while doing our regular river cruise, we were stuck in bumper to bumper traffic, due to the "Taste of Saskatchewan" festival that was going on, and we were unaware of!
Anyway, while moving at the speed of a physically challenged snail, my temp gauge climbed to the 230 F mark.:eek: In any other vehicle I've owned, this would've caused a small heart attack, but when investigating it on the "all reliable" WWW, this appears to be normal, or at least quite common.
Now when we got back home and let it cool off, I noticed the coolant was below the "COLD - FULL" mark a fair bit. I ended up having to add about a half liter to the reservoir, in order to get it back to full mark, and have been keeping a close eye on it, while driving around town and while its parked, and there are absolutely no leaks under the car!
Is this normal? Do I have a head gasket going possibly? Bad reservoir cap? Or am I just overthinking the whole thing?
Personally I prefer my engine to run as cool as possible, so if there's anything I can do, I'm open to doing whatever it takes to rectify the issue. Thanks in advance for any and all responses/help.
Click to expand...


On my C5 I was stopped on a fairly steep grade and the "low coolant light" came on. I stopped to check the fluid and everything was OK and the light was off. So when I got home I started looking around and checking things and the washer fluid was LOW. After topping it up I never had the warning come on again. Maybe someone knows if the two warning systems are connected???
Maybe it's worth a look at your windshield washer fluid level - can't hurt???
 
dkw said:
On my C5 I was stopped on a fairly steep grade and the "low coolant light" came on. I stopped to check the fluid and everything was OK and the light was off. So when I got home I started looking around and checking things and the washer fluid was LOW. After topping it up I never had the warning come on again. Maybe someone knows if the two warning systems are connected???
Maybe it's worth a look at your windshield washer fluid level - can't hurt???
Click to expand...
No I don't believe it's related, at least not in my case. I'm actually loosing coolant, and having to add, so it's going somewhere. Thanks for the response though.
 
So I have decided to start with easiest/cheapest parts that may be causing the hi temp issues, and work my way up. Yes I do realize that I may replacing parts that aren't in need of replacement yet, until I do find the culprit and I'm ok with that. These parts will likely need to be replaced at some point anyhow.
So this "was" my plan:
1) Inspect for leaks, inspect fan functionality and Properly clean rad, without removing. (Done)
2) Start with a fresh flush of the system, and add correct mixture. (Done)
3) Replace reservoir cap. (Done)
4) Replace T-stat.
5) Replace water pump assembly.
6) Upgrade rad and fans.
7) replace head gaskets (and heads while I'm at it)

As you can see, I have "Done" behind the first three items, and it seemed that the issue was better once the reservoir cap was changed, but now I have a visible small leak, which appears to be coming from the water pump. I've ordered the water pump assembly, and T-stat but if anybody has any good tips or vids on how to remove and replace, that would be great! I do have the three '99 service manuals, and I'm sure I'll manage, but any help that cuts down time, or cuss words is appreciated.
 
So the water pump, was NOT the issue. Looks like the heads coming off. Unfortunately, or fortunately, depending how you look at it, I am considering parking the "Mistress" for a year or two, depending on how long it takes, and how much money it takes, to complete the project, that I was hoping not to start for a couple of years yet, but find myself with this problem/opportunity!
I will be going to a turbo set up, not sure about single or twin yet, but I have a lot of information that I've retrieved, and have much more to find yet. The end goal will be to have street friendly, 700-800hp C5. Obviously the engine is just one part of the car that will need some upgrades, so like I mentioned, this may take a couple of years, depending on available funds. As upset as I am about possibly parking the car, and not being able to drive it for a couple years, I'm also cautiously excited to get this started. I am going to think about this for a week or two, and make my final decision but the wife and I had a lot of plans with the car this summer that will have to be cancelled, or we will be doing it in the Mercedes:mask:
 
Hey Dub... Sorry to hear that your car will be laid up for a bit but sounds like there is a definite speed of light at the end of the tunnel...
 
Sorry to hear Dub! Sounds like you're in the same boat I'm in at the moment. I can't for the life of me figure out why mine keeps overheating. Rad is clean, I'm NOT losing any coolant, thermostat seems to be opening, fans are working, and yet temps are climbing into the 250 range even while driving at highway speeds. I'm going to to a hydrocarbon test to see if combustion gasses are getting into the coolant. At this point, my guess is yes. :Banghead:
 
Dub sorry to hear of your problems, frustrating for sure. However the project sounds like a very interesting follow along story and I look forward to what you are going to do with it.

N20Vette and Dub is there any way of hooking up a mechanical gauge to see if the temperatures you are seeing are real? Has there been any history of inaccurate readings from electronic gauges?

Best of luck to both of you.
 
Hey Dub.
My car always seemed to run warm - 220 and I could keep the temps down ok by running the a/c.
First thing to always check on a C5 is that there is not a bag or debris blocking the radiator as our cars are bottom breathers and have a habit of picking up crap off the streets.
Mine was fine and it turned out that my coolant tank (surge tank) had a small crack in the nipple where the rubber tube attaches to. It was a small leak. I never saw coolant on the ground or leaking down the side of the tank.
However, I knew it was cracked due to the coolant getting darker and I could see just a bit of dried residue on the outside.
I replaced the tank and had the fans tuned to come on at 180 for stage 1 and 200 for stage 2. It's been great ever since.
Long story long, do you have any small cracks or pin holes in the system? Is the coolant still super clean or is it a bit brown like oxygen is getting in it?
Lastly, as another person interesting in getting twin turbos for my car, I'm interested to hear what other mods you are considering (may have to start a new thread). But my thoughts were for starters, new clutch, tunnel plate, DTE brace, and trans brace. Then down the line if needed, motor mounts, new bushings in the torque tube, hardened half shaft in the diff, and rebuilt transmission.
What have you thought of? My goal would be 500 rwhp so not quite as high as your 7-8 hundred.
 
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