LS400 Blown head gasket??
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I have a 97 LS400. It’s not overheating but it’s running higher than normal on the temp gauge. Also white smoke is coming out of tailpipes at start up. No water in oil though. And heater is blowing cool air. Any help appreciated
#2
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Does your coolant level drop over time? What is the coolant level now? Don't run the engine or drive the car until you at least confirm the engine has the proper coolant level.
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Head gasket failure on UZ engines is EXTREMELY rare. The white smoke at startup is coming from the air control valve attached to the PS pump. The valve allows air to enter the intake which raises the RPMs to assist steering feel under load like when turning at lower speeds. Over time the valve leaks small amounts of PS fluid which ends up entering the intake causing the white smoke at startup. Almost every 400 ever made does this at some point.
Check the basics first, your issue might be solved with a $10 thermostat 👍
#5
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heater blowing cool = air in the coolant. need to burp further. if you think you are done, keep going for another 10 mins of burping.
white smoke = more likely the power steering idle up valve leaking PS fluid into the intake.
https://www.clublexus.com/forums/ls-...valve-fix.html
white smoke = more likely the power steering idle up valve leaking PS fluid into the intake.
https://www.clublexus.com/forums/ls-...valve-fix.html
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I did service the coolant system and I installed a new thermostat. I suck at this burping. And the white smoke. I bet for sure it’s the power steering cause it makes noise. What do I replace on power steering pump? A whole new one? And how to keep burping?
It use to run at the second line. Now it runs between the second and third line. On temp gauge
It use to run at the second line. Now it runs between the second and third line. On temp gauge
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#8
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The air control valve is leaking allowing fluid to be pulled through the vacuum line resulting in that puff of white smoke at start-up. More of an irritation but the main issue is if the seals on the PS pump are leaking and dripping PS fluid onto the alternator. That PS fluid will kill the alternator and that is a high priority to fix. If that is the case find a mater Toyota/Lexus tech or if you want DIY with the correct Toyota PS rebuild kit. The aftermarket PS pumps are a gamble. Then while out install a new air control valve. Also recommended is to replace the vacuum lines.
For burping park the car so that it is slightly nose up and remove the reservoir cap and or the bleeder bolt. Heater on and let it idle away for 5-10 minutes.
For burping park the car so that it is slightly nose up and remove the reservoir cap and or the bleeder bolt. Heater on and let it idle away for 5-10 minutes.
#9
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for the PS air control valve, see the link from the FAQ below, referred to as the ACV:
https://www.clublexus.com/forums/ls-...ystem-diy.html
as for burping, i wanted to add that you are suppose to raise and hold the RPM at 2-3k for about 10 mins (found more success at 20 mins) to work all the bubbles out.
more on the link below (i recommend toyota long life "red" coolant as opposed to what is used here):
http://www.lexls.com/tutorials/cooling/coolant.html
https://www.clublexus.com/forums/ls-...ystem-diy.html
as for burping, i wanted to add that you are suppose to raise and hold the RPM at 2-3k for about 10 mins (found more success at 20 mins) to work all the bubbles out.
more on the link below (i recommend toyota long life "red" coolant as opposed to what is used here):
http://www.lexls.com/tutorials/cooling/coolant.html
#10
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But I did find 5 thermostats at Rockauto under $10 and 3 more for $10 and change
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https://www.rockauto.com/en/catalog/...hermostat,2200
#12
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Omg I should be knocked in the head.
Most of them are under $10, I must not have even looked at rockauto cuz their shipping is usually pretty high to my house. I'll put that on my list of all parts needed. Thnx.
Edit: I actually just checked and even with the shipping from rockauto they're cheaper by $4 then the local store. But your link is for a 98 and OP has a 97 which are different part #s. Don't want anyone ordering the wrong part (like I almost did)
https://www.rockauto.com/en/catalog/...hermostat,2200
Also, seeing how we're talking thermostats, what does anyone think of the "fail safe" technology on the Motorad in premium section? I put that in my other 93 years ago with no problem. (that's all Autocrap had in stock) If the car overheats and the "fail safe" activates, (locking t-stat open) then the T-stat needs to be changed. But it saves the engine from overheating and causing other damage.
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Edit: I actually just checked and even with the shipping from rockauto they're cheaper by $4 then the local store. But your link is for a 98 and OP has a 97 which are different part #s. Don't want anyone ordering the wrong part (like I almost did)
https://www.rockauto.com/en/catalog/...hermostat,2200
Also, seeing how we're talking thermostats, what does anyone think of the "fail safe" technology on the Motorad in premium section? I put that in my other 93 years ago with no problem. (that's all Autocrap had in stock) If the car overheats and the "fail safe" activates, (locking t-stat open) then the T-stat needs to be changed. But it saves the engine from overheating and causing other damage.
Last edited by deanshark; 11-11-21 at 11:48 AM.
#13
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You might want to check out the thread I started recently, it may address some of your issues. Btw, I'm in the midst of an experiment and unfortunately won't be able to post a complete and updated analysis until sometime in the Spring.
https://www.clublexus.com/forums/ls-...placement.html
Good luck,
LS400FAN
#14
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LS400FAN
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i really think the problem with the OP is just air in the coolant = not a bad HG. no oil in the coolant is a giveaway and other symptoms point to just air bubbles in the coolant.
of course we don't know until the OP posts his actual results;
of course we don't know until the OP posts his actual results;
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