Go Back   Horizons Unlimited - The HUBB > 4 wheels > Light Overland Vehicle Tech
1KZ-TE engine - how it works; specifically, the cooling system 1KZ-TE engine - how it works; specifically, the cooling system
Register FAQ Calendar Today's Posts
Light Overland Vehicle Tech Tech issues, tips and hints, prepping for travel
Under 3500kg vehicles, e.g. Land Cruiser, Land Rover, Subaru etc.
Photo by Hendi Kaf, in Cambodia

I haven't been everywhere...
but it's on my list!


Photo by Hendi Kaf,
in Cambodia



Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 19 Sep 2013
Registered Users
Veteran HUBBer
  
Join Date: Mar 2007
Location: UK
Posts: 4,343
1KZ-TE engine - how it works; specifically, the cooling system
I don't much like linking to other websites but even less do I intend to ever join a whole string of bulletin boards, thereby condemning myself to far too many hours spent online.
However, I can't resist the thread linked below, which gives an interesting insight into how the 1KZ-TE engine cooling system works; but are the theories therein correct??
Cooling the 1KZ-TE motor:

__________________
Dave
Reply With Quote
  #2  
Old 19 Sep 2013
Registered Users
Veteran HUBBer
  
Join Date: Nov 2009
Location: J10 M40 UK
Posts: 362
seemed ok to me , I can also understand why fitting the lower thermostat, will keep the head temp down , as the stat is sensing the block temp lower in the engine which would be lower than head temp , it may be that the head temp is getting above the flashboil point with a hightemp, low fitted thermostat. This would be most likely when working very hard . toyota must have a reason for fitting the thermo where it is but could be due to emissions as that seems to govern most things these days .
Reply With Quote
  #3  
Old 1 Oct 2013
Contributing Member
Veteran HUBBer
  
Join Date: Jun 2005
Location: Ledbury, Herefordshire, UK
Posts: 324
A good write up, however running a 76 degree thermostat isn't necessarily the silver bullet that Bob seems to think - it is more likely the fact that he completely rebuilt the cooling system that he didn't get any further problems

All fitting a 76 degree thermostat does is make an engine designed to run at 82 degrees run cooler than designed. How much difference to the internals and general running I don't exactly know.

In most cases the head gasket problems tend to be down to a number of factors like corrosion in the cooling system from not using genuine Toyota coolant, leaks from the rear heater pipes leading to over heating, radiator leaks (more often from fitting cheap radiators), viscous coupling problems, etc.

The bottom line is that the cooling system and head gasket are very sensitive on the 1KZ-TE so they need to be looked after. We have rebuilt three in the last month including our own being done now and all due to coolant leaks.
__________________
Cheers,

Julian Voelcker
Overland Cruisers - Specialising in Land Cruiser preparation and servicing.
Reply With Quote
  #4  
Old 11 Oct 2013
Registered Users
Veteran HUBBer
  
Join Date: Mar 2007
Location: UK
Posts: 4,343
Quote:
Originally Posted by tacr2man View Post
toyota must have a reason for fitting the thermo where it is but could be due to emissions as that seems to govern most things these days .
So, it's likely that the long, detailed discussion in the link has no substantial errors (such as the direction of the coolant flow).
I wonder if any other Toyota engine designs have the same, or similar, location for the thermostat?
Maybe the replacement D-4D engine??
It seems to have the even longer name, the "1KD-FTV".
http://en.wikipedia.org/wiki/Toyota_KD_engine



Quote:
Originally Posted by JulianVoelcker View Post
The bottom line is that the cooling system and head gasket are very sensitive on the 1KZ-TE so they need to be looked after. We have rebuilt three in the last month including our own being done now and all due to coolant leaks.
There's a lot of comment online about the 2.4 litre engine (as fitted in the "Surf" for example) with regard to head gasket problems, but this is the first time I have read about this issue with the 3.0 litre engine; it is also fitted in later versions of the "Surf" vehicles, I believe, + it is fitted in lots of "Colorados" and "Prados".
Does the D-4D engine suffer from the same sensitivity to the overall maintenance of the cooling system?
__________________
Dave
Reply With Quote
  #5  
Old 21 Oct 2013
Registered Users
HUBB regular
  
Join Date: Sep 2008
Location: UK
Posts: 41
I cant comment on using a different or the location of the thermostat etc but you should be ware that the 1KZ-TE suffers from another potential problem when it is coupled with an automatic gear box.

The radiator cools the ATF as well as the engine. It has been known for the ATF cooling pipes in the rad to corrode allowing coolant to mix with the ATF causing major problems in the auto gear box. Toyota coolant helps minimise this risk, but it is possible, as a preventative and relatively cheap fix, to fit a separate ATF radiator by-passing the standard rad and eliminating the risk.

As Julian says, the cooling system on the 1KZ-TE needs to be looked after and the use of Toyota coolant minimises the risk of corrosion.

AFAIK the D4D does not suffer from these problems.
Reply With Quote
  #6  
Old 22 Oct 2013
Registered Users
Veteran HUBBer
  
Join Date: Jan 2001
Location: Cork,Ireland
Posts: 150
I sold my SWB 90 recently with over 275k miles on the clock.
I only ever had one issue with the cooling system, on the motorway the needle would rise until it was at 10'oclock it usually sat just below 9 oclock.

Flushing the system did nothing to stop this problem however replacement of the radiator cured it.
The engine never gave any trouble with the cooling system apart from that one instance.
Points to note: This was a Manual SWB with base spec, no Aircon and no automatic.
With the Aircon the flow through the radiator can be quite slow especially if the area between radiators is not kept clean, also Automatic versions put extra heat into the cooling system.
On their own these are probably not enough to cause an issue, together with a radiator that is getting slightly blocked and extra heat load from speed or load this could cause the head to overheat.

I understand that Toyota fit resistors in the temperature gauge to slow the range of movement to avoid customers complaining about the temp needle moving during normal operations, this could also cause problems as many people never check the dash and by the time the needle is in the upper range it could be damaged.
Reply With Quote
Reply

« Previous Thread | Next Thread »

Currently Active Users Viewing This Thread: 1 (0 Registered Users and/or Members and 1 guests)
 

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Finally, a single cylinder adventure bike colebatch Which Bike? 305 27 Aug 2015 17:04
THis works in dusty conditions for engine intake! laplander Equipping the Overland Vehicle 0 29 Sep 2012 21:02
XT600E 2002 Engine Oil Trichelia Yamaha Tech 17 17 Nov 2011 15:25

 
 

Announcements

Thinking about traveling? Not sure about the whole thing? Watch the HU Achievable Dream Video Trailers and then get ALL the information you need to get inspired and learn how to travel anywhere in the world!

Have YOU ever wondered who has ridden around the world? We did too - and now here's the list of Circumnavigators!
Check it out now, and add your information if we didn't find you.

Next HU Eventscalendar

25 years of HU Events
Be sure to join us for this huge milestone!

ALL Dates subject to change.

2025 Confirmed Events:

Virginia: April 24-27 2025
Queensland is back! May 2-4 2025
Germany Summer: May 29-June 1 2025
CanWest: July 10-13 2025
Switzerland: Date TBC
Ecuador: Date TBC
Romania: Date TBC
Austria: Sept. 11-14
California: September 18-21
France: September 19-21 2025
Germany Autumn: Oct 30-Nov 2 2025

Add yourself to the Updates List for each event!

Questions about an event? Ask here

See all event details

 
World's most listened to Adventure Motorbike Show!
Check the RAW segments; Grant, your HU host is on every month!
Episodes below to listen to while you, err, pretend to do something or other...

Adventurous Bikers – We've got all your Hygiene & Protection needs SORTED! Powdered Hair & Body Wash, Moisturising Cream Insect Repellent, and Moisturising Cream Sunscreen SPF50. ESSENTIAL | CONVENIENT | FUNCTIONAL.

2020 Edition of Chris Scott's Adventure Motorcycling Handbook.

2020 Edition of Chris Scott's Adventure Motorcycling Handbook.

"Ultimate global guide for red-blooded bikers planning overseas exploration. Covers choice & preparation of best bike, shipping overseas, baggage design, riding techniques, travel health, visas, documentation, safety and useful addresses." Recommended. (Grant)



Ripcord Rescue Travel Insurance.

Ripcord Rescue Travel Insurance™ combines into a single integrated program the best evacuation and rescue with the premier travel insurance coverages designed for adventurers.

Led by special operations veterans, Stanford Medicine affiliated physicians, paramedics and other travel experts, Ripcord is perfect for adventure seekers, climbers, skiers, sports enthusiasts, hunters, international travelers, humanitarian efforts, expeditions and more.

Ripcord travel protection is now available for ALL nationalities, and travel is covered on motorcycles of all sizes!


 

What others say about HU...

"This site is the BIBLE for international bike travelers." Greg, Australia

"Thank you! The web site, The travels, The insight, The inspiration, Everything, just thanks." Colin, UK

"My friend and I are planning a trip from Singapore to England... We found (the HU) site invaluable as an aid to planning and have based a lot of our purchases (bikes, riding gear, etc.) on what we have learned from this site." Phil, Australia

"I for one always had an adventurous spirit, but you and Susan lit the fire for my trip and I'll be forever grateful for what you two do to inspire others to just do it." Brent, USA

"Your website is a mecca of valuable information and the (video) series is informative, entertaining, and inspiring!" Jennifer, Canada

"Your worldwide organisation and events are the Go To places to for all serious touring and aspiring touring bikers." Trevor, South Africa

"This is the answer to all my questions." Haydn, Australia

"Keep going the excellent work you are doing for Horizons Unlimited - I love it!" Thomas, Germany

Lots more comments here!



Five books by Graham Field!

Diaries of a compulsive traveller
by Graham Field
Book, eBook, Audiobook

"A compelling, honest, inspiring and entertaining writing style with a built-in feel-good factor" Get them NOW from the authors' website and Amazon.com, Amazon.ca, Amazon.co.uk.



Back Road Map Books and Backroad GPS Maps for all of Canada - a must have!

Your ad could be here, on EVERY page of the HUBB, or the whole website, or as many as you like!

New to Horizons Unlimited?

New to motorcycle travelling? New to the HU site? Confused? Too many options? It's really very simple - just 4 easy steps!

Horizons Unlimited was founded in 1997 by Grant and Susan Johnson following their journey around the world on a BMW R80G/S.

Susan and Grant Johnson Read more about Grant & Susan's story

Membership - help keep us going!

Horizons Unlimited is not a big multi-national company, just two people who love motorcycle travel and have grown what started as a hobby in 1997 into a full time job (usually 8-10 hours per day and 7 days a week) and a labour of love. To keep it going and a roof over our heads, we run events all over the world with the help of volunteers; we sell inspirational and informative DVDs; we have a few selected advertisers; and we make a small amount from memberships.

You don't have to be a Member to come to an HU meeting, access the website, or ask questions on the HUBB. What you get for your membership contribution is our sincere gratitude, good karma and knowing that you're helping to keep the motorcycle travel dream alive. Contributing Members and Gold Members do get additional features on the HUBB. Here's a list of all the Member benefits on the HUBB.



All times are GMT +1. The time now is 08:10.

Contact Us - Horizons Unlimited Motorcycle Travellers Website - Archive - Privacy Statement - Top