Brad400

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

LeX2K

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.

Brad400

It’s parked. The reservoir and the bolt on top where you add are both full.

bradland

What do you consider higher than normal on the temp gauge?
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 👍

timmy0tool

iTrader: (7)

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

RA40

iTrader: (6)

Did you recently service the cooling system? Are there any signs of leakage from the heater control valve on the firewall? As Timmy mentions about getting the air out of the system.

Brad400

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

RA40

iTrader: (6)

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.

timmy0tool

iTrader: (7)

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

deanshark

10 bucks for a thermostat? I read that and I thought this was from 20 yrs ago. I was looking a few days ago and I could only find $17 for aftermarket, plus gasket. If only $10, where do you get your parts and how much of a discount do they give you? I'm actually looking for alot of parts cuz I just bought another LS which I will describe in another thread.

bradland

HaHa, you're right Dean, I guess I was speaking figuratively.....
But I did find 5 thermostats at Rockauto under $10 and 3 more for $10 and change
https://www.rockauto.com/en/catalog/...hermostat,2200

deanshark

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.

LS400FAN

Hey Brad:

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

LS400FAN

Hey Bad Brad400, what's the latest on your possible head gasket issue, did you get the problem fixed? Tia.

LS400FAN

timmy0tool

iTrader: (7)

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;

• Last Activity: 11-12-21 09:12 PM
• Join Date: 11-07-21