Confused about a Cooling problem
Jun 23, 2005 | 06:31 PM
#12
Launching!
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From: Orlando, FL
Stange problem. Usually overheating is more common around town...Make sure that your fans aren't shutting down at high speeds, some do. I don't know how to verify this though.
Things to try:
To find if there is air in the system, try unplugging one of the throttle body coolant lines. That is usually the highest point in the system and the best to bleed the air from. Also make sure that your heater core is bled as well. Have the heater running as you bleed the system.
If that doesn't work, if you have the towing package, hit the tow/haul button. See if it still overheats in the lower gear/ higher rpm. Another thing is that if the radiator is too low of a restriction, colant won't have time to cool as it is passing through the radiator. This mixed with a leaner than stock condition (aftermarket tune?) will cause a overheat usually in OD.
Try these out and let me know.
-Chuck
'03 DSG Lightning *sold*
'05 GMC Sierra WT 4.8L
Things to try:
To find if there is air in the system, try unplugging one of the throttle body coolant lines. That is usually the highest point in the system and the best to bleed the air from. Also make sure that your heater core is bled as well. Have the heater running as you bleed the system.
If that doesn't work, if you have the towing package, hit the tow/haul button. See if it still overheats in the lower gear/ higher rpm. Another thing is that if the radiator is too low of a restriction, colant won't have time to cool as it is passing through the radiator. This mixed with a leaner than stock condition (aftermarket tune?) will cause a overheat usually in OD.
Try these out and let me know.
-Chuck
'03 DSG Lightning *sold*
'05 GMC Sierra WT 4.8L
Jun 23, 2005 | 09:09 PM
#13
Have you tried going down the highway without the superchips tune in it? I know I'm kinda reachin, but what if they have it tuned way lean and at high speeds the increased cylinder temps are transfering to the block and coolant?
Jun 23, 2005 | 09:21 PM
#14
Banned
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From: From Houma La. Living n Ellisville Miss.
Originally Posted by 02denali
are the fans going the right direction? i ran into this problem when i was doing the 80e swap. mine ended up being the top fitting in the rad. it is the one that goes from the rad to the fill tank. 1/2 inch hose. the fitting in the rad has a tiny hole in it. the rad shop drilled it out all the way. after that no more problems. i also keep that hose off while refilling the cooling system. then i usually started up the truck and let it fully warm up with out the cap on. good luck. maybe the therm is sticking at one point. it is not lewtting coolant flow fast enough at higher speeds.
Jun 23, 2005 | 09:28 PM
#15
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From: From Houma La. Living n Ellisville Miss.
Originally Posted by budhayes3
Have you tried going down the highway without the superchips tune in it? I know I'm kinda reachin, but what if they have it tuned way lean and at high speeds the increased cylinder temps are transfering to the block and coolant?
IT WOULD HAVE TO BE LEAN AND HE WOULD HAVE TO HOLD IT AT THAT SPEED FOR A WHILE,BUT CAN'T RULE IT OUT IT COULD BE ANYTHING
Jun 24, 2005 | 03:28 PM
#16
On the way home from work a half hour ago and it was 90 outside and put the cruise on at 75 mph and in tow/haul mode and the temps still went up after a while. Then wondering if it was rpm related I put it in 3rd and rpm's went up by like 800 or so and the temp went up faster. 
Waiting for the truck to cool off and then I'll check for air at the throttlebody bypass tubes to see if its there.
Waiting for the truck to cool off and then I'll check for air at the throttlebody bypass tubes to see if its there.
Jun 24, 2005 | 03:37 PM
#18
TECH Apprentice
Joined: Dec 2004
Posts: 393
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From: San Antonio
Originally Posted by 04BlackSilverado
On the way home from work a half hour ago and it was 90 outside and put the cruise on at 75 mph and in tow/haul mode and the temps still went up after a while. Then wondering if it was rpm related I put it in 3rd and rpm's went up by like 800 or so and the temp went up faster.
Waiting for the truck to cool off and then I'll check for air at the throttlebody bypass tubes to see if its there.
Waiting for the truck to cool off and then I'll check for air at the throttlebody bypass tubes to see if its there.
Jun 24, 2005 | 11:42 PM
#20
11 Second Club
Joined: Jul 2002
Posts: 1,424
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From: Beaver Falls, PA
air pocket. leave the cap off the recovery bottle (while it's cold) and start it up. let it reach operating temperature and rev it a few times. shut it off and let it cool completely. make sure the tank is plenty full so it can draw in coolant or you will end up at square one all over again. do this twice and see what happens.
