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Discussion Starter · #1 ·
On the way to work, notice the shitty stock gauge is higher than normal which I know to be a bad sign. Open up torque pro and it says 240. Sit for a little bit then start going again and it goes down to about 208 then back up to almost 230. Pull over again and let it sit for a bit and check under the hood. Coolant is boiling, not low or anything. Go a little further and it's cycling between 210 and 230, and finally starts going above that and I say eff it and stop with this shit. Is that enough info to point me in a direction or do I just need to tow it to the shop and start diagnosing?
 

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Did you do any work on it recently, got bubbles of air in the system?
 

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Discussion Starter · #3 ·
No nothing engine related for a quite a while
 

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If it was me id do it and the water pump. Weird that it cycled like that.

Ive always correlated if temps go down while moving but up while stopped then its the water pump

Are your fans turning on?
 

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Discussion Starter · #5 ·
Well it was going up at highway speeds. On a related note, at what temp should I start getting depressed because I may have cracked a head or something?
 

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Well it was going up at highway speeds. On a related note, at what temp should I start getting depressed because I may have cracked a head or something?
Idk id lean water pump. If its not moving the water then its not getting cooled through the radiator. Id do both still.
 

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Discussion Starter · #7 ·
I did notice the upper rad hose wasn't pressurized like I expected it to be.
 

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Do your basic troubleshooting. Check for air in the system. Check to make sure you got full levels of coolant. Check the oil for the forbidden milkshake. Make sure the fans are working. If you aren't comfortable doing all that, take it to a shop for an inspection.
 

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Thermostat could be sticking. You can put that in a pot of water and start to boil it and see if it opens when it hits 180-190 degrees.
 

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Thermostat could be sticking. You can put that in a pot of water and start to boil it and see if it opens when it hits 180-190 degrees.
Itd be just as easy to put a new one at that point. Guess itd confirm which issue but i wouldnt put it back in
 

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Well it was going up at highway speeds. On a related note, at what temp should I start getting depressed because I may have cracked a head or something?
Personally, I doubt you hurt anything reaching the temps you hit.

In addition to all the comments above I'll add a few. Since you said you were on the highway I would also check for obstructions on the front of the condenser and radiator to ensure adequate air flow.

Another idea; When the car is cold, take off the radiator cap (not overflow) start the car, turn the heat temp to full hot and let the heater run. Leave the car idle and let it get hot enough to open the thermostat. Observe the inside of the radiator and you should see coolant moving through the core. This may tell you if the thermostat and water pump are working. You should see coolant move and stop a few times. It helps to have an ODB scanner in your hand and monitor the coolant temp. In my car the coolant will flow when the gauge reads about 204 and stop about 191. If you have good flow it is possible the radiator is the problem. This will also purge any air out of the system.

How many miles are on the car? Has the coolant ever been changed? Has any maintenance been done to the cooling system that you are aware of?
 

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Discussion Starter · #12 ·
Do your basic troubleshooting. Check for air in the system. Check to make sure you got full levels of coolant. Check the oil for the forbidden milkshake. Make sure the fans are working. If you aren't comfortable doing all that, take it to a shop for an inspection.
I am, just wanted to ask in case I didn't think of everything. I did a cursory search on here real quick but I was a little freaked out being on the side of the road.

Thermostat could be sticking. You can put that in a pot of water and start to boil it and see if it opens when it hits 180-190 degrees.
Itd be just as easy to put a new one at that point. Guess itd confirm which issue but i wouldnt put it back in
I had already planned on doing just that as a test, should be pretty quick and easy.

Personally, I doubt you hurt anything reaching the temps you hit.

In addition to all the comments above I'll add a few. Since you said you were on the highway I would also check for obstructions on the front of the condenser and radiator to ensure adequate air flow.

Another idea; When the car is cold, take off the radiator cap (not overflow) start the car, turn the heat temp to full hot and let the heater run. Leave the car idle and let it get hot enough to open the thermostat. Observe the inside of the radiator and you should see coolant moving through the core. This may tell you if the thermostat and water pump are working. You should see coolant move and stop a few times. It helps to have an ODB scanner in your hand and monitor the coolant temp. In my car the coolant will flow when the gauge reads about 204 and stop about 191. If you have good flow it is possible the radiator is the problem. This will also purge any air out of the system.

How many miles are on the car? Has the coolant ever been changed? Has any maintenance been done to the cooling system that you are aware of?
Just turned over 83k, it has green coolant in it from the previous owner. I'd planned on changing it with prestone all vehicles whatever it's called this spring but never got around to it. Looks like it's forcing the issue..
 

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In my other car I’ve drilled small holes in the stat to get water or air moving should you get an air pocket. In some cars it’ll take longer to warm up so if you do, drill small hole(s).

I’ve had a goat get hot enough to lose power and turn off. Coolant spewed out from The rad during a drive and ran bone dry.

I recall GM set high fan on temps on the C5 and 3rd gen Camaro, something like 230 or so, so you “should” be ok.
 

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I recall GM set high fan on temps on the C5 and 3rd gen Camaro, something like 230 or so, so you “should” be ok.
yeah, i would agree. i forget what the stock fan settings are, but 230 doesn't seem high. if you didn't get an overheat warning on the DIC you should be good. Crap, there have been plenty of times that's gone off and i've been fine, just needed to shut the engine down right away. LS engines can take a bit of punishment. Not that I would push it on purpose or anything, lol.

it could be as simple as the radiator cap not holding pressure and letting the coolant boil.
 

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Discussion Starter · #15 ·
Say my troubleshooting leads to a bad water pump, what's the forum's 2021 consensus on which one get? Any old auto parts store/rock auto pump that works? Go with the ac delco? Is there anything to this post from jontall?
 

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Say my troubleshooting leads to a bad water pump, what's the forum's 2021 consensus on which one get? Any old auto parts store/rock auto pump that works? Go with the ac delco? Is there anything to this post from jontall?
In another thread, I asked about a mystery AF smell and hidden places it could leak. A few people said water pump, and I doubted it, because I had already replaced it. I've noticed I have hints of white crusty stuff on the WP pulley (check it every time I stop now) so it is very likely a WP leak that's tiny and slinging a little coolant.

I looked up my receipt and it was replaced in 2013 with an AC Delco. It lasted maybe 35k miles. Tonight, I ordered a Gates water pump, T-Stat and cap from Rockauto.

I used to sell Gates and Airtex back in the day, and would gladly use either one without hesitation. After having a AC Delco 'new' compressor on my truck crap out early, and this WP, I'm going to go with something I have a more solid feeling about.

Good luck..
 

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Discussion Starter · #18 ·
I went to the shop a little early to check the coolant level as it warms up and remove the tstat for testing. The coolant level didn't budge at all all the way up to 210°. Even if the tstat was stuck shut I would have thought it would do something. And combine that with the upper rad hose not getting pressurized yesterday and I'm solidly leaning water pump too. Still torn between the 200$ acdelco and a cemetery Gates.
 

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I went to the shop a little early to check the coolant level as it warms up and remove the tstat for testing. The coolant level didn't budge at all all the way up to 210°. Even if the tstat was stuck shut I would have thought it would do something. And combine that with the upper rad hose not getting pressurized yesterday and I'm solidly leaning water pump too. Still torn between the 200$ acdelco and a cemetery Gates.
Sounds like you are right with the water pump. It is possible the thermostat is stuck closed. Since you are opening the system up to swap the pump, I would recommend doing the thermostat as well. As for what pump, I’d use the gates.

You could pull the thermostat and put it in boiling water to see if it opens. I am one of these people who like to know what broke. 😎
 

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Remember that AC Delco use to have two levels of product. AC Delco Professional was the Parts Store Special options and the AC Delco Original Equipment or something was the actual factory surplus quality part.

They rebranded AC Delco parts and now "GM Genuine" is the actual OEM level part. If the GM Genuine is actually made at a GM in-house facility, and not a 3rd party supplier, you won't find a Gates or Dayco, or whatever that is the same thing in a different box.

That doesn't mean you won't find a quality private brand, just know that "AC Delco" doesn't mean you're done making a selection.
 
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