Replace your original thermostat
#1
Lexus Champion
Thread Starter
Replace your original thermostat
My 1999 LS400 had its original thermostat...
Recently noticed warm up times had increased considerably so extracted the thermostat for inspection and found the internal seal inside the thermostat assembly had split and was holding the thermostat valve open...
Gas mileage was down...
Lucky this did not get sucked into engine...
The rest of the thermostat internals were fine but the rubber had degraded with age and use.
If you have an original thermostat, replace it with an OEM part...they are reasonably priced. So no excuse for aftermarket...
DO NOT USE AFTERMARKET crap. About a 3/4" piece of internal rubber seal (not the housing to thermostat seal) had split and wedged between thermostat valve preventing engine warm up.
Parts required..thermostat, thermostat housing seal and crush washer for throtlle body coolant filling cap (1998-2000 LS400)
Coolant filling port is atop throtlle body assembly.Replace cap crush washer.
Recently noticed warm up times had increased considerably so extracted the thermostat for inspection and found the internal seal inside the thermostat assembly had split and was holding the thermostat valve open...
Gas mileage was down...
Lucky this did not get sucked into engine...
The rest of the thermostat internals were fine but the rubber had degraded with age and use.
If you have an original thermostat, replace it with an OEM part...they are reasonably priced. So no excuse for aftermarket...
DO NOT USE AFTERMARKET crap. About a 3/4" piece of internal rubber seal (not the housing to thermostat seal) had split and wedged between thermostat valve preventing engine warm up.
Parts required..thermostat, thermostat housing seal and crush washer for throtlle body coolant filling cap (1998-2000 LS400)
Coolant filling port is atop throtlle body assembly.Replace cap crush washer.
Last edited by YODAONE; 10-28-17 at 09:18 AM.
The following users liked this post:
saleenssc (10-30-17)
#4
mine went around 180K miles on my 1999 LS, I noticed the gas mileage got bad, changed it with OEM, simple job, easier than an oil change.
I now have 238K, all is well
I now have 238K, all is well
Last edited by valex; 10-28-17 at 07:15 PM. Reason: adding
#5
Thanks for the great post and pictures of the part numbers needed for this job.. I have been considering changing mine on my 98 which has 180k on it. Your post has inpired me to change mine as well.
quick question. How much coolant did you lose or need to re-fill ? also where did you get the crush washer (part number 90430-20017) ? Lexuspartsnow.com has it for $1.64 but they want $12+ for shipping (ouch). do i just go to my local dealer for this part?
thanks
quick question. How much coolant did you lose or need to re-fill ? also where did you get the crush washer (part number 90430-20017) ? Lexuspartsnow.com has it for $1.64 but they want $12+ for shipping (ouch). do i just go to my local dealer for this part?
thanks
Last edited by saleenssc; 10-30-17 at 05:54 AM.
#6
Lexus Champion
Thread Starter
Thanks for the great post and pictures of the part numbers needed for this job.. I have been considering changing mine on my 98 which has 180k on it. Your post has inpired me to change mine as well.
quick question. How much coolant did you lose or need to re-fill ? also where did you get the crush washer (part number 90430-20017) ? Lexuspartsnow.com has it for $1.64 but they want $12+ for shipping (ouch). do i just go to my local dealer for this part?
thanks
quick question. How much coolant did you lose or need to re-fill ? also where did you get the crush washer (part number 90430-20017) ? Lexuspartsnow.com has it for $1.64 but they want $12+ for shipping (ouch). do i just go to my local dealer for this part?
thanks
Order parts from your Lexus dealer..not much savings online with these parts
The following users liked this post:
saleenssc (10-30-17)
#7
Great tip! I'm glad I had mine done with the timing belt and water pump. My school of thought is whenever a larger service like that is done, then I best replace the smaller items. Also whenever there is a potential for the thermostat to be exposed to air, I always replace them. That is of course after they have been in service for a while.
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wnyjazz (11-01-17)
#9
Lexus Champion
Thread Starter
#10
Racer
#11
Lexus Champion
Thread Starter
Anyone with original thermostat?
21 to 31 year old thermostats are well past their sell by date.
The thermostat employs an internal rubber seal.
Either by mileage or age, it is prone to failure.
Inexpensive preventative maintenance.
The thermostat employs an internal rubber seal.
Either by mileage or age, it is prone to failure.
Inexpensive preventative maintenance.
#12
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