1998 LS400 Air Con Condenser fan (or lack thereof)

[Supafly]

Last week sitting in a drive through queue I noticed for the first time that the coolant temperature made a run for the red.  The coolant temperature has always been consistent and I've never had cause for concern.

So I ordered:

Radiator    16400-50150

Thermostat    90916-03100

Thermostat gasket    16346-50010

ecu coolant temperature sensor    89422-30030

along with some of lexus/toyota's finest red  08889-80006

Some context on the car which I've now had the pleasure of owning for nearly five years.  I test drove a few LS400's and this was by far the best driving and mechanically sound of all four.  However, it had been in an accident towards the front and O/S and has what looks like a Japanese spec front bumper.  Also there was no paperwork or service history with the car.  This didn't concern me as it was in such good mechanical condition and the bodywork I knew I could live with until I got round to sorting it.

 So when I started work on the car I realised that there is no electric condenser fan.  I thought maybe it was damaged and removed when it was 'repaired'.  So I looked at getting a SPAL pusher fan and fitting it as an upgrade over the missing original fan...  This is when things got weirder.  After checking manuals and researching online I took out the NS headlight to get access to the relay box that should house the AC cooling fan relays (x3).  To my surprise there is no box, I was expecting to find some hacked up wiring but there doesn't seem to be any trace of it.

My air con works although doesn't get extremely cold straight away, and takes a little while to make the car uncomfortably cold.  Hence I've never investigated any further than having the system recharged a couple of years ago.

 

My question is, do some UCF20's not have an electric condenser fan and the relay box no 6?

Also, there was no sensor in the bottom corner of the original radiator.

 

[Malc]

I've read your post and have absolutely no idea personally how to help you with any useful thought

Good luck

Malc

[steve2006]

Having looked at the parts diagrams for both the 1998 Lexus LS400 and the Japanese equivalent model Toyota Celsior I think you may have the latter.

The Japanese version does not have the relays missing in yours or the condenser fan, so it would seem you either have a converted Celsior ( Fitted with Lexus badges etc) or the complete front end has been replaced with a Celsior section.

Does the vehicle have a complete UK MOT history? Also ask Lexus if they could provide any service history information (normally a free print off when proof of ownership established).

Also is the cooling fan belt driven or hydraulic?

Take a look under the passenger footwell left side for a black plastic tube.

[Supafly]

2 hours ago, Malc said:

I've read your post and have absolutely no idea personally how to help you with any useful thought

Good luck

Malc

Thanks for the thought, I think I'm going to need a good dose of luck too 🙂

[Supafly]

1 hour ago, steve2006 said:

Having looked at the parts diagrams for both the 1998 Lexus LS400 and the Japanese equivalent model Toyota Celsior I think you may have the latter.

The Japanese version does not have the relays missing in yours or the condenser fan, so it would seem you either have a converted Celsior ( Fitted with Lexus badges etc) or the complete front end has been replaced with a Celsior section.

Does the vehicle have a complete UK MOT history? Also ask Lexus if they could provide any service history information (normally a free print off when proof of ownership established).

Also is the cooling fan belt driven or hydraulic?

Take a look under the passenger footwell left side for a black plastic tube.

I really appreciate your help with this.

It's definitely a UK LS400 but the repair does look like it's using a Japanese spec bumper, has no headlight washers and there is a 'ariel/flag post/parking marker' on the NSF corner.

It has a belt driven viscous coupling fan which isn't brilliantly close/sealed to the radiator shroud but I've realised that this is a feature to enable radiator removal without having to take the fan off.

I'm in the office today but will check when I get home under the car.

[Supafly]

My current thinking is either leave it alone as I'm replacing almost the entire cooling system and it was working well before except this last incident on one of the hottest days... or fit a temp switch to the vacant rad position and wire in a spal push fan from a relay activated by the radiator switch.

What has thrown me is the lack of relay box no.6 under the NSF headlight, which also has me wondering how the AC is controlled.

[Supafly]

I didn't see a black plastic tube under the passenger footwell.

I've put it back together now and also changed the oil control valves. 

Need to get some more coolant from lexus in the morning then bleed it and see how it maintains temp. I'm confident it'll be OK, but now wondering if I should install a fan on the condenser. 

[ambermarine]

The euro version ( UK )of the Mark 4 LS400 was not fitted with a condenser fan the engineers at Lexus deemed the climate cool enough to dispense with the fan as the condenser was capable of cooling the a/c at that time ,recent climate conditions have turned that on its head but proves their thynopsis.

[Supafly]

1 hour ago, ambermarine said:

The euro version ( UK )of the Mark 4 LS400 was not fitted with a condenser fan the engineers at Lexus deemed the climate cool enough to dispense with the fan as the condenser was capable of cooling the a/c at that time ,recent climate conditions have turned that on its head but proves their thynopsis.

Thank you very much for confirming.  I think their engineers deserve credit too.

Over two decades of wear and tear and record temperatures is too much to be planned for.  That is more for us as owners to recognise and mitigate.  Which is why I just ordered the parts and replaced it all.

The only thing I haven't changed is the viscous coupling.  I did test it and it was working well.  For future reference I've found that these are serviceable and that the fluid is available from Lexus/ Toyota part # 0881610001

[Supafly]

Update following first drive. 

 

Before setting off I sat in the car while idling and with the AC on cold in auto mode. The car had been sitting in direct sunlight. 

The temperature rose past the second mark and towards the halfway point, then I noticed the needle dip ever so slightly towards the second mark (I'm guessing this is after the thermostat opened). Then it sat between the second mark and halfway on the gauge.  I waited for twenty minutes to see if it would creep up but it didn't. 

Then went for a fifty mile drive each way to Leicester and back and everything seems fine.  It also feels like the air conditioning is slightly colder than before. Probably down to the cleaning of the condenser. 

I don't think I'll need an additional fan but when I started it up with the ac on I was surprised at how hot the condenser was.

So for me at least, this was a successful repair that gave me the opportunity to get a few jobs done in one go.

[Supafly]

 

 

video showing how to change the fluid in the viscous coupling

[steve2006]

You don’t want to be the guy who fitted an extra cooling fan for the 7 odd days of a “record” British summer 😀

[Supafly]

2 hours ago, steve2006 said:

You don’t want to be the guy who fitted an extra cooling fan for the 7 odd days of a “record” British summer 😀

🤣🤣🤣

Who knows we might have 7.5 days next year and I might regret not modifying it! 😆

[Supafly]

Interesting update...

My nephew was in the car with me the other day and pointed out my average mpg.  It has increased by approx 5mpg. 17-18 now up to 22-23 mpg.

It reminded me of other threads where people have changed their ECT sensor and noted an increase in mpg.

I also replaced both oil control valves at the same time too as I already had them, and it was easy to change them while I was doing this work, so not sure if that contributed anything towards it.  I don't think there was anything wrong with mine but I had bought them when I first noticed a slight missfire which was resolved with a new set of plugs.