Do I have air in the coolant system? - ClubLexus - Lexus Forum Discussion

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Do I have air in the coolant system?

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Old 01-16-14, 09:55 AM
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davincity
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Default Do I have air in the coolant system?

So I just did a major tune up and timing belt service/radiator on my 91 LS with 220k. Car ran nearly perfect before and still does. The only problem is after the coolant change, whenever the car warms up it seems to like "burp" or make a swallowing feelings when accelerating at certain speeds, and at idle yesterday sitting in a drive-thru taco bell, every 20-30 seconds it would make that burp feeling. My car temp was a little high so I grabbed a used thermostat from a different LS to see if it would drop the temp & it appears this thermostat is also bad because temp is normal in the city but it rests at about C on the freeway.
Also wondering if a tranny flush/filter will fix this problem. Around 40mph the car will slightly stall sometimes before taking off below 2rpms (overdrive fixes this 2 year problem). Also in reverse the car takes about a second to lock into the reverse. Any help thanks guys.
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Old 01-16-14, 09:59 AM
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BTW I have an OEM thermostat coming today or tomorrow
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Old 01-16-14, 10:28 AM
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make sure the new thermostat has its jiggler hole in the 12 o'clock position and get a new Toyota radiator cap - then check level at the FILL BOLT (the downward facing bolt behind thermostat housing) and make sure it's full - make sure overflow take is at correct level

if you do all of that, and you have no leaks, cooling system will self-bleed via repeated hot/cold cycles, just keep checking coolant level and topping up at overflow over the next few days

PS - when you are filling at fill bolt, have car running with heater on max and give the big hoses a periodic squeeze and keep topping up
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Old 01-16-14, 02:34 PM
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bubbles in the coolant should not affect driving performance to where you can feel it while driving, unless the car is actually overheating.

do what cowboy stated first making sure the heater is on full and car on when filling.

if the problem persists i would then change the coolant temp sensor.
https://www.clublexus.com/forums/ls4...read-this.html

if it still happens, it may be your ECU capacitors.
https://www.clublexus.com/forums/ls4...capacitor.html
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Old 01-16-14, 09:05 PM
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Thanks guys, I will do the above, also flush the transmission fluid and see if that helps.
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Old 01-16-14, 11:22 PM
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LScowboyLS
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Originally Posted by davincity View Post
Thanks guys, I will do the above, also flush the transmission fluid and see if that helps.
do NOT flush the transmission fluid, that can ruin a transmission! - hopefully you meant flush the cooling system!
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