Another New Years Surprise- Coolant Leak?

[aviator888]

Sitting at the traffic lights in Leicester City centre, noticed some smoke coming from.. under the hood of my Lexus Pulled over asap to check the damage, engine bay covered in coolant. Hurray! I was not able to see where is it coming from, but coolant reservoir still had juice left.

My brother owns a recovery truck i never tought i would have to ring him but i did not want to take any chances cooking the engine. Anyways got the car on my drive now.. temp gauge stays normal, oil looks ok, no grey smoke from exhaust. Waiting for daylight to take the covers off and check for leaks..

[Neil E]

Hope it's something simple like a hose spring clip failure. At least the engine didn't get hot.

[ambermarine]

This occurence is relevant to engine overheating and blowout of expansion reservoir .It happened when my mark1 had its water pump failure ,basically what happens is the coolant in the engine is not circulated evenly and expands to such a degree around the pots it forces its way out, resulting in the blowback.

Get the water pump checked first.

[aviator888]

This morning took the covers off and it didn't take long to find where the leak is

Im going to entertain myself by phoning Lexus Leicester on monday morning and see how much blood they want for a new radiator.

With a little help and advice i should be able to do the work by myself. The cambelt is done i can't find any records about water pump.. I think it's worth changing the water pump while the radiator is off.

[cruisermark]

how many miles on your car

[alien1974]

just change the rad and coolant should be ok

[ambermarine]

Not familiar with the 430 cooling rad or the expansion tank system but that round shaped object on the rad top looks like some kind of valve( could it be a pressure relief valve). Get the Lexus dealership to check the system as I have never heard of Radiators going on Lexus 400 or 430s for that matter.

[harrylime]

If you narrow it down to the radiator, it may well be repairable. I once got a price for an exchange Audi radiator at a motor factors, and as the price seemed high, decided to look for a radiator reconditioning specialist. I found one locally, who reconditioned my radiator for me. They were also the firm that supplied the motor factor. The difference was that it cost me around half.

[aviator888]

I found this image from http://www.lexussouthatlantaparts.com/showAssembly.aspx?ukey_assembly=1175318&ukey_make=1082&ukey_model=15670

Has anyone had any experience changing/repairing part 16441? Most likely i will change the whole assembly..

The car is on 130 000 miles and i think i will leave the water pump for now going by the old saying- if it's not broken don't fix it.

[hihihi]

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[aviator888]

Thanks Eff for advice, i am already looking for new rad from various websites.. prices start from £75 but i'd like to wait and see what the dealer quotes first.

I have also heard some very good feeback about "Radweld" type substances and i would not hesitate to use this stuff in 11-year old Ford/Vauxhall/BMW.. but this time i do not want anything else circulating in this beautyful V8 engine but coolant :)

[plexus914]

Are you sure it is the radiator and not the vent/plug/screw (comes with o-ring or some sort of gasket) on top of it? When adding coolant that plug has to be open due to air in the system.

[aviator888]

Positive. There is about 4 inch long crack runs just below the yellow sticker.

[Neil E]

Hi Mel

I think you are choosing the right option to replace the rad with a new one. They can be repaired but better to have the benefit of the full cooling capacity of a new one.

If the cam-belt has been done then it's likely the water pump was done at the same time. It's correct and common practice to do them at the same time.

[ambermarine]

Totally different to the ls400 cooling system in that there does'nt seem to be an expansion bottle for the fluid to go and come from during coolant temprature changes.

I was not aware that the body of the rad had split and again that maybe due to the fact pressures undesigned for have been created.

If at some time the system as been drained and not refilled as prescibed in the workshop manual an air lock will occur and this can cause a blowback or in this case a fracture of the rad.

I suggest you take it to Lexus and get the job done properly ,apart from the fact you are shelling out for parts that you might not have done so had a previous job been done properly,you don't want a re-occurence and they could shed some light on what happened in the first occurence.

[aviator888]

Totally different to the ls400 cooling system in that there does'nt seem to be an expansion bottle for the fluid to go and come from during coolant temprature changes.

I was not aware that the body of the rad had split and again that maybe due to the fact pressures undesigned for have been created.

If at some time the system as been drained and not refilled as prescibed in the workshop manual an air lock will occur and this can cause a blowback or in this case a fracture of the rad.

I suggest you take it to Lexus and get the job done properly ,apart from the fact you are shelling out for parts that you might not have done so had a previous job been done properly,you don't want a re-occurence and they could shed some light on what happened in the first occurence.

LS400 and LS430 are totally different cars.. as i found out today trying to change the HID bulbs on both sides. On LS400 it was easy as pie :)

Im confident about getting the job done myself. That includes bleeding the system properly. However what im not confident about is the quality of the cheap £100 radiators..

[aviator888]

So this is what the £100 radiator looks like :) Fitting was pretty straightforward, only the coolant overflow hose had to be extended.

While the radiator was off, i also fitted new drive belt, because old one got probably soaked in coolant.

Next job on my list is to sort out the alloy wheels (refurbishment) and a little bit noisy power steering pump.

[brendangeorge]

Good luck - did you check your thermostat (mine jammed and caused a lot of steam and me grief). Make sure you do up the bleed screws after you have bled the system. I had a local indi change my Cam belt which resulted in a new Rad at 200K miles - not their fault it was just old - and we had fun getting the air out of the system.

My Rad was £300+ the cheap ones did not fit my 2002 model.

Bren

[aviator888]

Good luck - did you check your thermostat (mine jammed and caused a lot of steam and me grief). Make sure you do up the bleed screws after you have bled the system. I had a local indi change my Cam belt which resulted in a new Rad at 200K miles - not their fault it was just old - and we had fun getting the air out of the system.

My Rad was £300+ the cheap ones did not fit my 2002 model.

Bren

On cheap rads the overflow outlet is located next to the filler cap so the hose going into coolant tank has to be replaced with longer one. OEM ones do not have filler cap and are by far, better quality parts. Still there's no reason why cheap replacement would not fit Your car other than peace of mind maybe. My old LSis happy with it, but i would not even consider fitting these parts if it had LS460 or 600h badge on the boot :)