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Location:
Sydney
Registered:
July 2005
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Lexus V8 coolant temp
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Sun, 03 July 2005 04:58
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Hi,
I have a 1uz-fe and i'm trying to find out the operating temperature of the motor. I thought if someone is running an aftermarket computer or gauge they may know what temperature their motor runs at. Any help would be greatly appreciated.
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: Lexus V8 coolant temp
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Sun, 03 July 2005 05:47
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Stock Thermostat is 82degC
So the car runs at about 85ish while cruising, tad less if you have a bigger radiator.
My thermo's turn on at 96degC and off about 86degC
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Location:
Sydney
Registered:
July 2005
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Re: Lexus V8 coolant temp
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Sun, 03 July 2005 06:09
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The reason i ask is is my 1uz runs at about 90deg but as soon as you give it a bit it starts to rise to +95deg. With the thermostat in place i found it couldn't maintain 90deg at idle and would rise to +95deg. So i'm know forced to run without a themostat to try and keep things somewhat driveable. It's something i can't work out. The motor is mated to a 3core reco holden v8 radiater, new cap, overflow tank and two 10inch thermo's mounted to a shroud on the back of the radiater. Uses toyota coolant and the motor should have about 100k so i can't imagine the water pump could be faulty. Any ideas??
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: Lexus V8 coolant temp
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Sun, 03 July 2005 06:12
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I'm using the twin AU thermo's, and they are more than enough.
Sounds like you either have a big air pocket, or the radiator is blocked.
If you didn't flush the block before installing the motor, or haven't had the radiator cleaned since starting the motor, then it could very well be blocked.
Mine is only the stock 86 cressida 2 core radiator and it does the job with ease.
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Location:
Sydney
Registered:
July 2005
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Re: Lexus V8 coolant temp
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Sun, 03 July 2005 07:28
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Thanks for your ideas and reply.
The radiator was reco'd and i did it remove after these problems and tested the flow with a garden hose (not under pressure) and all was good.
I bleed the system using the large bolt on the top of the thermostat housing. I actually attached fittings and a bleed tap running through a clear hose to this to make the process it a little easier.
I have'nt flushed the block out though. When i recieved the motor it still had the toyota red coolant in it and before installation i removed both water crossover pipes and thermostat housing, no corrosion and all was imaculate. I know it's not impossible but i can't imagine it could have a blockage. I might look at removing the radiator and running the motor through tubs of water to check the flowrate. Any idea on the flow rate?
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Lexus V8 coolant temp
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Sun, 03 July 2005 07:44
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silly question, but have you verified that the thermostat actually opens?
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: Lexus V8 coolant temp
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Sun, 03 July 2005 07:48
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I wouldn't worry about home testing anything.
Flowrate through the block should be fine.
Do as Stu suggested above and pop the thermostat in a pot of hot water, make sure it opens.
Then just give the radiator to a shop, and have them open it up and check all the tubes.
Clean radiator, opening thermostat, should provide a cool motor while running.
Maybe you'll need an underguard to improve airflow at speed.
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Location:
Sydney
Registered:
July 2005
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Re: Lexus V8 coolant temp
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Sun, 03 July 2005 08:20
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I bought a new thermostat when i installed the motor and then another one for testing later on. I then tested both side by in a jug of water on a stove with a thermostat. What i found during testing was actually interesting, this promted me to buy the second thermostat. I found they didn't open till around 87deg and they wern't fully open till about 92-93deg this was i little surprising as there both stamped with 82deg. Both vary in there design slightly as the previous one was discontinued when i purchased the second one. But at the end of the day the only way to actually keep the thing somewhat drivable was to remove it altogether and block the back passage to the water pipe as the thermostat would do in it's fully open position.
I also have made a guard underneath out of aluminium and removed the back rubber on the bonnet to promote flow.
Maybe i should remove the radiator and have it checked but it was in great nick and flowed well with the garden hose (not under pressure) passing through the core. It would take another thing out of the equation though
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: Lexus V8 coolant temp
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Sun, 03 July 2005 08:44
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I have a genuine Toyota thermostat in mine.
I suspected it was dead, so I tested it.
Started opening about 82degC, and was fully open by about 90, maybe 92.
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Location:
Sydney
Registered:
July 2005
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Re: Lexus V8 coolant temp
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Sun, 03 July 2005 09:22
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Yeah mine were genuine thermostats also. To be honest they had slight movement at about 84deg but only a fraction not enough to flow any coolant.
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Location:
Brisbane
Registered:
June 2003
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Re: Lexus V8 coolant temp
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Sun, 03 July 2005 13:03
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two 10" fans would not be enough for a 1uz cooling imo...the Au fans are either 12 or 13"
And we all know a 13" probly sucks as much as two 10s....
try one big ass thermo if u can fit it. A commodore fan off a vs (they have a short fan motor design) would be ideal. I just installed one on my uncles landcruiser, and it drops the temp from 90, to 85 in about 10 seconds LITERALLY!
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: Lexus V8 coolant temp
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Sun, 03 July 2005 13:09
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Two 10s on a 2-core radiator might not be enough, but on a 3-core radiator it should be plenty.
But even the biggest fan in the world isn't going to help keep the motor cooler at cruise/WOT, which I believe is where the main issue is.
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Location:
Sydney
Registered:
July 2005
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Re: Lexus V8 coolant temp
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Sun, 03 July 2005 13:56
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That's right you can cruise at 3000rpm all day at 90 deg which is high in itself but as soon as you raise the revs to 4000rpm or start to give it a bit that's where the major problems arise. I reckon it would only last a lap at a track before it would try and cook itself which is dismal to say the least. 
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: Lexus V8 coolant temp
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Sun, 03 July 2005 14:01
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And that in itself should never happen with a 3-core radiator
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Location:
Sydney
Registered:
July 2005
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Re: Lexus V8 coolant temp
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Sun, 03 July 2005 14:11
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Yep that's it. I'm throwing my arms up and grabbing another beer!!! 
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Location:
Sydney
Registered:
July 2005
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Re: Lexus V8 coolant temp
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Sun, 03 July 2005 14:22
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Ok to get some idea of my setup check out the general car talk section my mate Ben has posted up some pics of my car.
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Location:
Adelaide
Registered:
September 2003
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Re: Lexus V8 coolant temp
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Sun, 03 July 2005 14:58
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surely not head gasket?
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Location:
Canberra
Registered:
May 2002
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Re: Lexus V8 coolant temp
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Mon, 04 July 2005 07:23
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Hey man nice tidy setup, looks smooth.
A coupla questions, which might help with trouble shooting your problem.
What ECU are you running?
What temp sender are you using to activate the fans?
Where is the sender located?
What temp do the fans switch on, and off.
Have you verified, that the fans are forcing air through the radiator? Some are push, some are pull, and some are reversible, by flipping the blades over. Reversing the polarity, to change fan motor direction, is not as efficient as flipping the fans.
What is your fuel pressure? (too low pressure = lean mixture, = extra heat)
What type of EFI pump are you running?
cheers Chuck.
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: Lexus V8 coolant temp
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Mon, 04 July 2005 07:28
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Ignore the fans Chuck, it overheats at speed.
But the air/fuel ratios are definately something worth checking.
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Toymods Social Secretary
Location:
Sydney
Registered:
July 2002
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Re: Lexus V8 coolant temp
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Mon, 04 July 2005 10:08
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Hello, my name is Mr. Lean 
Well my experience with the factory 1UZ-FE cooling system has shown it to NEVER move a notch on the guage once it reaches temperature. That includes thrashing, cruising, cruising at RPM, sitting in traffic.... EVERYTHING.... never budges.
I'll hook up a decent thermoguage one day.
I tend to agree with Peewee here, you either have a blocked/cracked radiator, or your engine is running leeeeean! What's the tuning like??
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Location:
sydney
Registered:
March 2003
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Re: Lexus V8 coolant temp
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Mon, 04 July 2005 11:26
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toyota temp gauges suk ass
temp on my 1uz sits in middle and moves 2 mm either way sometimes
the temp on my scanner will range from 90 to 105 degrees and the temp gauge will barely move
this is common on most toyotas they need to get bloody hot for temp gauge to move
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Location:
Sydney
Registered:
July 2005
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Re: Lexus V8 coolant temp
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Mon, 04 July 2005 13:54
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Thanks again guys here goes:
-ECU: Autronic
-Temp sensor: Autronic water temp sensor, fans are controlled by the Autronic. I also have a VDO water temp gauge that verifies the same temp as ECU.
-Sensor Location: In the front crossover water pipe (factory location), both sensors.
-As far as fan on off temps go i've tried many combo's with little success and still overheats on freeway regardless. Current setting on 92deg off at 88deg. Not that they really spend any time off.
-Yep fans flow correct direction as far as reversing the blades something i have'nt noticed i'll take a look. But they currently flow a pretty serious volume of air.
-Checked fuel pressure and as per factory specs.
-Air fuel ratio all good checked and tuned on the Dyno just 1000km ago.
-EFI pump standard. Doesn't run lean all good.
-In the next day or two i think i'm going to remove the radiator and perform a flow test for myself. I may test the flow rate of the motor at the same time as i'm having no success in locating any specs on flow rates. Something i found in a workshop manual was interesting however. It was for a TE 4 cylinder cortina and the water pump specs are 200Litres a minute @5000rpm. I find that astonishing thats 3Litres a second.
Something for me to ponder.
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Toymods Social Secretary
Location:
Sydney
Registered:
July 2002
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Re: Lexus V8 coolant temp
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Tue, 05 July 2005 02:19
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testing water FLOW is one thing, as a radiator can still flow plenty of water, but not cool as effectively.
Take the radiator off, take it down to a respectable radiator shop (there's a guy in behind the pool hall on Carrington Rd, Castle Hill who is good!) and get them to check it out for you. They'll usually take off the end tanks, flush the core and "poke test" to clean it, and advise on what else could be the cause.
Well that's what i would do anyway 
**EDIT: extra afterthought..... if the radiator wasnt very well flushed and cleaned before installation and it previously used green coolant, the fact that you are now using Toyota RED coolant could be a BIG factor to consider!!
here's a FUCKING AWESOME link to the ARE website - they have shitloads of information on cooling - both engine block cooling and intake air cooling. This particular link is about aluminium radiators, but explains a little about why happens when two different types of coolants are mixed. Its a damn shame the pics are dead!
http://www.are.com.au/feat/techtalk/ALUMRAD.htm
[Updated on: Tue, 05 July 2005 02:27]
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Location:
Sydney
Registered:
July 2005
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Re: Lexus V8 coolant temp
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Tue, 05 July 2005 09:09
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Cheers 'Mr Lean'
That's a great link i've read through it in the past but not for a while. It's hard to find a shop who actually knows what there doing and gives a shit, so thanks for letting me know about the shop on Carrington Rd. It's local to so an added bonus as well. Have you had any work carried out there or is it just a word of mouth thing?
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Location:
Sydney
Registered:
July 2002
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Re: Lexus V8 coolant temp
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Wed, 06 July 2005 06:56
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I had a lot of issues with rising temperatures.
I agree with people above:
Get your radiator checked/reconditioned.
After doing everything I could think of (including electric water pump, replacing factory water pump, etc.) I found out my radiator was 75% blocked. 
ps. due to shit wiring (aka "the birdsnest"), I've been running without a fan of any kind for about 6 months. I simply turn it off if I know I'm going to sit at traffic lights for a while. Most of my driving is either short (5-10 mins) or long (highway), and never in traffic. Oh and my temp guage never moves unless I'm at a stop for an extended period of time.
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Location:
Sydney
Registered:
July 2005
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Re: Lexus V8 coolant temp
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Wed, 06 July 2005 09:57
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Hi Pete,
Your car look great i just checked out your site. I'm starting to lean towards the radiator being blocked myself. So are you running an electric pump currently or was that purely for testing? Do you know what the flow rating of the electric water pump is by any chance. What radiator are you currently running, alloy, core numbers and is it crossflow? Any help would be great, and thanks for your advice also. 
Cheers Mark
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Toymods Social Secretary
Location:
Sydney
Registered:
July 2002
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Re: Lexus V8 coolant temp
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Wed, 06 July 2005 11:40
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Mark,
yes i have actually had a bit of work done at the shop on Carrington Rd. He has fixed up and cleaned an AE101 4a-gze radiator (two tubes were busted open in an 'incident') for me, and cleaned my housemates valiant 3 core radiator. Good service, good price, and he seems to take good care in what he does.
He has also done a fair bit of work on a turbo Suzuki Vitara that lives across the rd from me
I would say blocked radiator for sure!
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Location:
Sydney
Registered:
July 2002
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Re: Lexus V8 coolant temp
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Wed, 06 July 2005 13:14
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| THE WITZL wrote on Wed, 06 July 2005 21:40 |
I would say blocked radiator for sure!
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I'm with stupid ^ 
My radiator is the standard MA70 one. Other people would be able to give you specs on it.
The electric one was put on to "save power" etc. was a big headache, after going through 3 electric pumps and 2 mechanical ones (I've got a spare mechanical one if anyone wants to buy it??). The mechanical one does a much better job IMHO, on the lexus engine with the pipe configuration its simpler to keep it standard.
Also note: I'm running quite a large oil cooler as well, which helps when my thermo fan wiring dies. And keeps the oil much cooler for track days, not as much heat soak.
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Location:
Sydney
Registered:
July 2005
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Re: Lexus V8 coolant temp
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Wed, 06 July 2005 13:29
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Hey guys,
Thanks for your replies, and taking the time much appreciated. I'm crossing my fingers on the radiator even though it was supposed to be reco'd but you never know i guess unless you check for yourself. I'll take it out shortly and find out for sure. Thanks again for your help.
Cheers Mark
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Location:
Sydney
Registered:
July 2002
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Re: Lexus V8 coolant temp
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Wed, 06 July 2005 13:31
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Mark,
Let us know how you go.
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Toymods Social Secretary
Location:
Sydney
Registered:
July 2002
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Re: Lexus V8 coolant temp
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Wed, 06 July 2005 14:56
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pete - drop me a line re the water pump if it's the same as the crown pump. I'm planning a big service around the 120,000kay mark (get in early i say!)
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