Question about 1998 GMC Suburban
Engine has less than 5000 miles, new water pump, radiator is just over a year old, and new thermostat. New engine ran about 50 degrees hotter than the old one. Had the radiator flushed and refilled professionally. Recently had to replace freeze plug on the side of the block. Now the motor heats up until the check gauges light comes on, then cools down within normal operating range. It only does this after it has cooled off for a few hours. After it cools down into normal range it sometimes fluctuates but never gets as hot as it does after it has reached its peak of hot temp the first time. No smell of antifreeze inside or outside of car. no visible leaks either. No white smoke or smoke of any other kind coming from tailpipe, no water coming out of it either. And no coolant is visible in the oil. I recently put bars copper stop leak in it thinking it had a small drip somewhere that wasn't visible. This hasn't seemed to stop the problem either. It doesn't seem to use coolant either. I am by far not a certified mechanic but I do know my way around an engine and can usually fix whatever is wrong with it but I am completely at a loss with this one. Any help would be greatly appreciated as this is the only vehicle I have and is therefore my every day driver.
SOURCE: 2000 maxima overheating
You have a new radiator and thermostat, so your coolant was flushed. Was the radiator "burped" afterward to get rid of air bubbles? If not, that needs to be done first - it would explain virtually every symptom you're seeing.
Jack up the car so that the radiator cap is elevated. With the coolant
topped off, start the car and let it run until it's about 3/4 of the
way to overheating. Then shut it down and go have a beer. When it cools
off enough to safely open the radiator cap, do so, and any air trapped
in the system will bleed out.
What you're doing is circulating
the coolant and the air bubbles inside. The bubbles get lodged behind
the thermostat and stay there, keeping it from opening (this causes the
car to heat up). When you later pop the cap off the radiator, the
pressure is vented from the system, the thermostat opens, and the
bubbles pass through. They'll work their way to the radiator (since
you've got it elevated) and pop out the open cap opening.
Your
coolant level will likely drop somewhat after doing this, as the air
bubbles will be gone and the space they took up in the system is now
available. You may need to add a little more coolant, so top if off
(with the car back on the ground) and recap the radiator, fill the
overflow to the marked point on the tank, and you're good to go.
Try this if you haven't already, and post back up with your results. If it doesn't solve the problems, we'll take it further.
Posted on Aug 11, 2008
SOURCE: 1998 Dodge Durango no heat when using heater.
BLEND DOOR STUCK OR BROKEN. NEEDS TO REMOVE DASH AND HEATER/EVAP CORE BOS TO REPAIR REPLACE.
Posted on Jan 08, 2009
SOURCE: Same problem , car has only 86,000 miles
replace that thermostat again...flush radiator any way...then see how it runs...
Posted on Aug 28, 2009
SOURCE: 1992 GMC Suburban over cooled???
You may have been given the wrong thermostat. Either way, you can try a hotter thermostat. If the water pump has never been changed it might be time for a new one. I've already had one that was so old that the propeller inside had the fins rusted completely off and the bearings were so bad it was messing up the timing of the motor. The truck wouldn't idle. And guess where alll the rusted off propeller chunks ended up. . . that's right. In the radiator, heater core and the thermostat. I flushed that truck for three days in both directions to get all that scrap out of there. Good Luck. And if you still have the old thermostat you can always throw that one back in, just to see what happens.
Posted on Feb 25, 2010
SOURCE: 2004 cheverolet impala 3.4L engine
Sounds like you have an air;lock in your cooling system.Try placing a bleeder on the return hose to the heater core ........looks like a small tap
Posted on Aug 18, 2010
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the heat works great. forgot to mention that in my question.
One more thing. The coolant doesn't bubble or blow out of radiator if the cap is removed
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