Overheating, need a water pump writeup
 

i just joined this forum so i could get some help fixing my dad's 92 SC400...i tried searching for the answers, but i couldnt find what i was looking for...i'm new here, so please go easy on me

my dad was driving the car yday when it started to overheat...he pulled over...when i came there, i saw that there was a crack along the top of the radiator...i was trying to understand what would cause it to do that? the timing belt was changed at 110k miles (car now has 134K miles), but the water pump was NOT changed then...and i know this is about the mileage where they fail

i've taken the radiator out to go get it repaired if possible...and i will replace the thermostat as well...but i'm pretty sure the water pump is the cause of the overheating, because even after the car cooled down and i tried putting on the heater, it was blowing cold air...

i'm pretty mechanically inclined...i drive a 300ZX TT and have changed the water pump and done my own timing belt service on that car...in fact, i have done everything short of an engine pull...i know i can change out the water pump myself, but is there a writeup that shows step by step how to do it? if i had a "how to replace water pump" guide, it would easy for me...i tried searching, but couldnt find one for the SC...can someone provide me a link to it?

thanks for your help

Hey welcome,

Check the engine forums, where Im moving this to...or use the keyword search in the blue bar kinda under where it says "welcome arashid"...I'm not a SC400 owner, but from what I've read, you might as well do the timing belt while your into it.

https://www.clublexus.com/forums/sho...c400+Waterpump

https://www.clublexus.com/forums/sho...c400+Waterpump

https://www.clublexus.com/forums/sho...c400+Waterpump

If your radiator has split at the seam between the top and the main body - that is common (and dare I say it a purpose built fault point on OEM Radiators). Having them split / burst / separate in exactly that place is one of the single most common cooling system related items in an SC400. The good part of this hiccup is that a brand spanking new Radiator can be had for around 125 bucks and changing the thermo (about 14 bucks) is smack simple.

I would be very VERY comfortable telling you to just drain the coolant, get the new radiator in, new thermostat in and fill up with a bottle of the "Toyota Red" coolant from the Toyota parts desk and your pap will be all fixed up.

Google LexLS to find the website for tutorials on draining the existing coolant. That is a great site with photo driven tutorials for the 1UZ-FE engine. But I HAVE TO STRESS THIS!!!!! DO NOT USE DEXTRON BASED COOLANT IN THE 1UZ-FE for FARKS SAKE! Get the 15 dollar bottle of "Toyota Red" and know your safe and trouble free using it from the start. It's the newer style Ethol Glycol pink/red factory coolant MADE for our type of engines and it's specifically compatibe with the gasket and O-Ring materials in our engines.

In the end, for now it's highly unlikely your water pump needs a look. Get the new radiator in there after a flush and refill and you should be set.

thanks for the help...

i read those posts and a few others...my thermostat is opening up in a pot of boiling water, so i'm assuming its the water pump...

while those links were good, is there an actual write up of how to replace it? or is there a service manual online i could read? i couldnt find it on this site or on google...i dont wanna start ripping things apart since i am not familiar with this lexus

ok just read this after making my post...so are you saying that the OEM radiators are faulty? i guess the reason i was tempted to replace the water pump is because i'm not sure when it was last replaced...i'd rather replace it now and be worry free...i mean, its preventive maintenance...and i'd hate to replace the radiator and thermostat, only to find out the car is still overheating...then i would have to rip everything out again...

btw, where do you suggest buying a new radiator? are they a lot from the dealer? how are the aftermarket equivalents at Auto Zone or O'reilly?

thanks

Go with a oem replacement KOYO radiator. Perfect fit into the sc400.

This is a DIY for an LS400, but it is somewhat the same except a few minor differences. Gives you a general idea of it: http://www.lexls.com/tutorials/engine/timingbelt.html

thanks, yes i did see that DIY

is there a certain place or vendor i SHOULD get the radiator from? is there a well respected vendor? or just any auto parts store?

Try ebay, I see some for pretty decent prices.

quick update...i changed the thermostat and radiator the other day...my goal was to see if the radiator cracking was the problem of the overheating...and after switching both of them out, the car is back to normal...i'm gonna say the radiator was the issue...

i am aware i should change the water pump also just to be safe, and i'm gonna do that soon also

thanks for helping a visitor to the site...and just for no reason at all, quick pic of my car

http://www.photodump.org/stored16/IMG_0442Medium.jpg

That is one sick and sweet ride. I love those TT 300ZX's. I had a 1990 TT ZX and loved it...