98c5/a4 overheating
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Joined: Dec 2013
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From: Atlanta Ga.
Now I also noticed while it was boiling in the overflow tank that there was a tiny hissing sound coming from where the small black hose goes into it. I removed the hose and there is a tiny pin hole leak in the stem!! should i be worried about that now? doesnt do anything until it over heats right?
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From: Atlanta Ga.
Thread Starter
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Joined: Dec 2013
Posts: 78
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From: Atlanta Ga.
Yes you should be VERY concerned about a pin hole leak in the nipples of the surge tank that the hoses attach to.
Part of the design of the system is for pressure to be built when the coolant temp gets above 212 degrees. The coolant boil point of a 50/50 mix is around 220 degrees. But for every pound of pressure in the system the boil point is raised 3 degrees. So with a 15 lb cap on the system the coolant boil point becomes 265 degrees for a 50/50 mix. Boil point is an important issue. Once the coolant begins to boil the coolant does NOT remain in contact with the metal that it is trying to cool so the metal temp increases and the coolant boils faster resulting in even less contact with the metal so it gets even hotter..... SPIRAL effect....
You need to replace the surge tank if it is leaking and pressure is not being built up after 212 degrees. Replace, because the surge tank is a plastic material that cannot be resealed for more than a short period of time. Surge tank is available on Amazon for about $65 last time I checked. You need the tank built for 97 and 98 cars since it has a sensor for low coolant in the bottom of the tank. An electrical connector to which a wire is attached.
Again this is probably NOT going to correct the issue with the fans not coming on correctly but it will get the engine temperature down. As I said in my PM to you the engine was running too hot and this is why.
You WILL need to reburp the system once you replace the surge tank. Start with a cold engine and have it running while you loosen the bolt to allow air out of the system. BOTH SIDES!!! I would ALSO invest in a new pressure cap for the system. Probably about $15. The new cap will be for 18lbs and not the 15 that is most likely on the system now. GM went to 18lb caps for the C6 and stopped making the 15lb cap.
I will look up the part on Amazon and PM you a link.
Part of the design of the system is for pressure to be built when the coolant temp gets above 212 degrees. The coolant boil point of a 50/50 mix is around 220 degrees. But for every pound of pressure in the system the boil point is raised 3 degrees. So with a 15 lb cap on the system the coolant boil point becomes 265 degrees for a 50/50 mix. Boil point is an important issue. Once the coolant begins to boil the coolant does NOT remain in contact with the metal that it is trying to cool so the metal temp increases and the coolant boils faster resulting in even less contact with the metal so it gets even hotter..... SPIRAL effect....
You need to replace the surge tank if it is leaking and pressure is not being built up after 212 degrees. Replace, because the surge tank is a plastic material that cannot be resealed for more than a short period of time. Surge tank is available on Amazon for about $65 last time I checked. You need the tank built for 97 and 98 cars since it has a sensor for low coolant in the bottom of the tank. An electrical connector to which a wire is attached.
Again this is probably NOT going to correct the issue with the fans not coming on correctly but it will get the engine temperature down. As I said in my PM to you the engine was running too hot and this is why.
You WILL need to reburp the system once you replace the surge tank. Start with a cold engine and have it running while you loosen the bolt to allow air out of the system. BOTH SIDES!!! I would ALSO invest in a new pressure cap for the system. Probably about $15. The new cap will be for 18lbs and not the 15 that is most likely on the system now. GM went to 18lb caps for the C6 and stopped making the 15lb cap.
I will look up the part on Amazon and PM you a link.
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Joined: Dec 2013
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From: Atlanta Ga.
Yes you should be VERY concerned about a pin hole leak in the nipples of the surge tank that the hoses attach to.
Part of the design of the system is for pressure to be built when the coolant temp gets above 212 degrees. The coolant boil point of a 50/50 mix is around 220 degrees. But for every pound of pressure in the system the boil point is raised 3 degrees. So with a 15 lb cap on the system the coolant boil point becomes 265 degrees for a 50/50 mix. Boil point is an important issue. Once the coolant begins to boil the coolant does NOT remain in contact with the metal that it is trying to cool so the metal temp increases and the coolant boils faster resulting in even less contact with the metal so it gets even hotter..... SPIRAL effect....
You need to replace the surge tank if it is leaking and pressure is not being built up after 212 degrees. Replace, because the surge tank is a plastic material that cannot be resealed for more than a short period of time. Surge tank is available on Amazon for about $65 last time I checked. You need the tank built for 97 and 98 cars since it has a sensor for low coolant in the bottom of the tank. An electrical connector to which a wire is attached.
Again this is probably NOT going to correct the issue with the fans not coming on correctly but it will get the engine temperature down. As I said in my PM to you the engine was running too hot and this is why.
You WILL need to reburp the system once you replace the surge tank. Start with a cold engine and have it running while you loosen the bolt to allow air out of the system. BOTH SIDES!!! I would ALSO invest in a new pressure cap for the system. Probably about $15. The new cap will be for 18lbs and not the 15 that is most likely on the system now. GM went to 18lb caps for the C6 and stopped making the 15lb cap.
I will look up the part on Amazon and PM you a link.
Part of the design of the system is for pressure to be built when the coolant temp gets above 212 degrees. The coolant boil point of a 50/50 mix is around 220 degrees. But for every pound of pressure in the system the boil point is raised 3 degrees. So with a 15 lb cap on the system the coolant boil point becomes 265 degrees for a 50/50 mix. Boil point is an important issue. Once the coolant begins to boil the coolant does NOT remain in contact with the metal that it is trying to cool so the metal temp increases and the coolant boils faster resulting in even less contact with the metal so it gets even hotter..... SPIRAL effect....
You need to replace the surge tank if it is leaking and pressure is not being built up after 212 degrees. Replace, because the surge tank is a plastic material that cannot be resealed for more than a short period of time. Surge tank is available on Amazon for about $65 last time I checked. You need the tank built for 97 and 98 cars since it has a sensor for low coolant in the bottom of the tank. An electrical connector to which a wire is attached.
Again this is probably NOT going to correct the issue with the fans not coming on correctly but it will get the engine temperature down. As I said in my PM to you the engine was running too hot and this is why.
You WILL need to reburp the system once you replace the surge tank. Start with a cold engine and have it running while you loosen the bolt to allow air out of the system. BOTH SIDES!!! I would ALSO invest in a new pressure cap for the system. Probably about $15. The new cap will be for 18lbs and not the 15 that is most likely on the system now. GM went to 18lb caps for the C6 and stopped making the 15lb cap.
I will look up the part on Amazon and PM you a link.
Intermediate
Joined: Jun 2014
Posts: 29
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From: Londonderry NH
I may have missed it but did you check that the radiator and AC condenser are not clogged? sometimes it is easy to miss the simple stuff. Not that completely cleaning these is simple or easy.
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Thread Starter
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Joined: Dec 2013
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From: Atlanta Ga.
Well!!!! Back in the same boat again! The fan is not coming on again.. I'm wondering if the same relay they replaced has went bad again?? I switched relays out with the ignition relay and all seem to work. I did that last time though and Vengeance put a new relay in and it worked. this has been a huge PIA!
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From: Atlanta Ga.
Step 15 - When installing the new relay be sure the orientation is correct or the relay will not work.
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Joined: Dec 2013
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From: Atlanta Ga.
So the relay still remains a mystery!! So I just straight wired my fan to a toggle switch on the inside of the car! now I can turn it on when I need it! Works great! But it did not solve the problem! On my way to work this morning and in traffic it jumped up to 220 then 230 then 240..etc.. Pulled over and waited! Maybe its the new thermostat I just put in that's bad/sticking? No leaks or sounds from water pump. heater works great. This has been a nightmare. So I figure maybe changing the T-stat again or replacing the radiator! any more ideas??
thx..
thx..
Le Mans Master
Joined: Feb 2012
Posts: 6,644
Likes: 479
From: OK
So the relay still remains a mystery!! So I just straight wired my fan to a toggle switch on the inside of the car! now I can turn it on when I need it! Works great! But it did not solve the problem! On my way to work this morning and in traffic it jumped up to 220 then 230 then 240..etc.. Pulled over and waited! Maybe its the new thermostat I just put in that's bad/sticking? No leaks or sounds from water pump. heater works great. This has been a nightmare. So I figure maybe changing the T-stat again or replacing the radiator! any more ideas??
thx..
thx..
It seems like this happens a LOT whenever someone opens up the system...
https://www.corvetteforum.com/forums...erheating.html
Pro
Joined: Apr 2013
Posts: 502
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From: Huntsville, AL Relaxed!
I agree.....
I have done a LOT of work to my engine, and have never had an overheating issue. I'm not sure if I've just been lucky, or what....but every time I've filled the cooling system I've followed the same procedure: The front end is lifted high on jack stands. Leave the top radiator hose disconnected at the radiator, I leave it resting on the lip of the radiator inlet, AND the steam vent hose disconnected (the steam vent hose is disconnected under the throttle body) then I slowly fill the system at the expansion tank until coolant starts to come out of the radiator hose. I then install the radiator hose, and continue to SLOWLY fill the expansion tank....soon coolant will start to flow from the steam vent hose....let it flow until you see a steady stream.....then let it flow some more. Install the steam vent hose, and top off the exp. tank.
This has worked very well for me....I have a 408 that I drive pretty aggressively, and a LOT of time is spent in stop-and-go traffic in Seoul...the hottest I see is 220 deg.
IHTH,
KoreaJon
I have done a LOT of work to my engine, and have never had an overheating issue. I'm not sure if I've just been lucky, or what....but every time I've filled the cooling system I've followed the same procedure: The front end is lifted high on jack stands. Leave the top radiator hose disconnected at the radiator, I leave it resting on the lip of the radiator inlet, AND the steam vent hose disconnected (the steam vent hose is disconnected under the throttle body) then I slowly fill the system at the expansion tank until coolant starts to come out of the radiator hose. I then install the radiator hose, and continue to SLOWLY fill the expansion tank....soon coolant will start to flow from the steam vent hose....let it flow until you see a steady stream.....then let it flow some more. Install the steam vent hose, and top off the exp. tank.
This has worked very well for me....I have a 408 that I drive pretty aggressively, and a LOT of time is spent in stop-and-go traffic in Seoul...the hottest I see is 220 deg.
IHTH,
KoreaJon
Sounds like AIR... It seems like this happens a LOT whenever someone opens up the system...
https://www.corvetteforum.com/forums...erheating.html
It seems like this happens a LOT whenever someone opens up the system... https://www.corvetteforum.com/forums...erheating.html
Burning Brakes
Joined: Jun 2012
Posts: 803
Likes: 42
From: Destin Florida
Have you checked to see if CO is present in the coolant? The same condition you are having can be caused by a head gasket leak. If nothing else it rules that out. Simple test can confirm.
Last edited by ssrallyred; May 28, 2016 at 12:56 PM.