Big leak of coolant under my 2008 ISF

etienne1201 · February 11, 2018

Hello, I'm from France so apologize for the spelling mistakes ...

I took a few weeks ago my 2008 LEXUS ISF to an independent mechanic I know to install the USRS kit, bleed the brake fluid, repaint the front bumper, the bonnet and the 4 wheels.

I got my car back on Friday, February 9, I traveled 50 km to go home and everything was ok. The next afternoon, I drove 20 km and back in my garage I see a big leak of coolant and a big puddle under the car! The big problem is that the liquid is a little greasy and mixed with oil.

With a friend we found the origin of the leak: When I start the car, after 3 seconds, the big engine coolant supply hose becomes hard and the coolant leaks through the hose too much full right next to the coolant reservoir cap.

The coolant in the tank has a milk chocolate color.

What is your diagnosis? Do you think this is related to the passage of the car at the independent mechanic or is it a bad coincidence? I will contact my car mechanic tomorrow to discuss it.

ColinBarber · February 11, 2018

I can only think the coolant is contaminated with engine oil or transmission fluid. I would check the levels of both engine and transmission.

I suspect the radiator/pipe work had a knock during the work done by your mechanic and it has damaged the transmission oil cooler inside the radiator and it is leaking transmission fluid into the coolant.

It is very important that you don't draw coolant into the transmission so I wouldn't use the vehicle again, or possible disconnect the transmission pipes going to/from the radiator and join them together - bypassing the cooler in the radiator.

etienne1201 · February 12, 2018

Peter P18 · February 13, 2018

Hey Etienne,

Can you check inside oil cap please? Need to see if there are any signs of a mayonnaise type gunk in there. If so, looking like a blown head gasket, which would be extremely odd and rare.

Personally liking the US suggestion about the gearbox cooler in the radiator failing, still not ideal, but has to be better than a head gasket failure?

etienne1201 · February 13, 2018

As a precaution, I contacted my insurance agent who took my car with a tow truck and took it to the LEXUS garage. I spoke with the workshop manager and he will try to look at this today. To answer the various questions, the engine oil level is ok and the oil has a nice normal color, there is no mayonnaise inside the oil filler cap.

Big Rat · February 13, 2018

@etienne1201 Etienne good luck with the result in the broader scheme of things you've probably taken the wisest course of action.

Big Rat

Peter P18 · February 13, 2018

27 minutes ago, etienne1201 said:

As a precaution, I contacted my insurance agent who took my car with a tow truck and took it to the LEXUS garage. I spoke with the workshop manager and he will try to look at this today. To answer the various questions, the engine oil level is ok and the oil has a nice normal color, there is no mayonnaise inside the oil filler cap.

Excellent stuff Etienne.

Sounds like it's probably the cooler leak discussed over on the US forum, or something less serious than a head gasket failure at the very least!

Look forward to hearing further once you hear back from Lexus. Fingers crossed it's nothing too serious or costly.

ThebigC · February 13, 2018

i thought i'd added my 2 pence yesterday but obviously not lol.

glad that you have made some progress in finding out the problem, when i read the post last night the "valley plate" issue came to mind straight away but i thought that was just a US thing... hope you get sorted sharpish buddy!

etienne1201 · February 13, 2018

For information, this morning the tow truck man started the car to put it on his truck and he restarted to put it down to the LEXUS garage parking. During this last maneuver he had to accelerate hard enough for the car to move, as if the parking brake was engaged. Could it be a lack of pressure in the transmission? I hope my explanation is pretty clear ...

ColinBarber · February 13, 2018

8 minutes ago, etienne1201 said:

For information, this morning the tow truck man started the car to put it on his truck and he restarted to put it down to the LEXUS garage parking. During this last maneuver he had to accelerate hard enough for the car to move, as if the parking brake was engaged. Could it be a lack of pressure in the transmission? I hope my explanation is pretty clear ...

Yes, potentially that could be the case.

etienne1201 · February 14, 2018

Bad news : The LEXUS workshop manager just called me, the coolant is contaminated with transmission fluid (radiator dead). He called a gearbox specialist who told him that the gearbox was probably dead because the coolant is attacking the clutch discs.

The workshop manager advises me initially to replace the radiator and to drain twice the transmission, but without guarantie of success.

What is your opinion?

stevet · February 14, 2018

10 minutes ago, etienne1201 said:

Bad news : The LEXUS workshop manager just called me, the coolant is contaminated with transmission fluid (radiator dead). He called a gearbox specialist who told him that the gearbox was probably dead because the coolant is attacking the clutch discs.

The workshop manager advises me initially to replace the radiator and to drain twice the transmission, but without guarantie of success.

What is your opinion?

Exactly the same happened to a Shogun I had. The previous owner replaced the radiator then sold the car to the garage I bought it off. Within 2 weeks the clutch discs went. Under warranty they had the gearbox reconditioned and then ran great for years as our tow car.

Big Rat · February 14, 2018

@etienne1201 Etienne sorry about that fella if it helps you there is an isF that used to belong to a member that was rolled on the motorway a short time back but the car itself is intact as such so there is a very real possibility the box is fine.

Ive rang the dismantling people where the car is if this is an option for you they are looking for £1750.00 for the gearbox that's about €2000.00, the guy to speak to there is Bill who deals with the Lexus side of things, the link to the company is below.

http://www.lexusbreakers.co.uk/

There are photographs of the car on the site, I know of this car and pre crash condition was fantastic.

There are pre accident pictures on the forum of the car and a video as well.

Good luck with sorting it fella.

Big Rat

etienne1201 · February 14, 2018

Thank you very much @Big Rat !!!

I'm waiting for the result of the drain, I hope I will not have to replace gearbox ...

ColinBarber · February 14, 2018

It is probably worth trying to save the transmission. You need to get all the coolant out of it. Just draining and filling the pan isn't enough because 50% of the fluid is held within the torque convertor and valve body.

You need to drain/refill the pan and then pump out the old fluid by disconnecting the oil cooler and starting the engine. Let 0.5 litre pump out, turn off the engine, add 0.5 litre of new fluid, and repeat until you have replaced all the fluid - and step through the different gears whilst pumping out to make sure all the valves are flushed through.

Big Rat · February 14, 2018

7 minutes ago, etienne1201 said:

Thank you very much @Big Rat !!!

I'm waiting for the result of the drain, I hope I will not have to replace gearbox ...

@etienne1201 No problem happy to help, yep see what happens what harm can it do now anyway.

Big Rat

etienne1201 · February 14, 2018

I have just received the quotation for the replacement of the radiator, the flushing of the gearbox and coolant: 1730 € / 1522 £ (8h of labour).

ColinBarber · February 14, 2018

58 minutes ago, etienne1201 said:

I have just received the quotation for the replacement of the radiator, the flushing of the gearbox and coolant: 1730 € / 1522 £ (8h of labour).

I hope your independent mechanic is going to pay?

etienne1201 · February 14, 2018

I think it's almost impossible to prove that the breakdown is related to the passage of the car in his garage

etienne1201 · March 9, 2018

Hi,

Bad news, the gearbox is dead! Change twice the oil was not enough. The gearbox skids and all the torque doesn't go to the wheels.

I have 2 solutions today : either refurbish the gearbox or buy a second hand.

A mechanic friend of mine will do for me the removal and reassembly of the gearbox.

What do you think is the best and fastest way to remove the tranny? Remove only the gearbox or take out the engine + tranny?

I found LEXUS ISF used gearboxes from 2010 and 2011 at good prices and I asked the LEXUS workshop manager if they could fit on my 2008 car. He replied that from December 2007 to August 2009 the gearbox reference is 35000-53130 and that since August 2009 the reference is 35000-53140.

In your opinion is still good or not?

Peter P18 · March 9, 2018

Sorry to see this Etienne.

Personally, I'd probably go with removing both the engine and gearbox. Good opportunity to give it a once over and also do the sparkplugs whilst it's out of the engine bay.

Don't believe there were any fundamental changes to the gearbox design throughout the entire production run? I'd ask over on the US forum to be sure, but I am sure you should be ok fitting a post 2009 gearbox to your car.

Hope you get it sorted out my friend.

All the best,

Peter

etienne1201 · May 18, 2018

hello,

the gearbox of my ISF has been replaced by a used which I previously validated the serial number at my LEXUS dealer.
My mechanic friend who did the work has restarted the car but there are many fault codes, the forward gears do not work well, only the reverse works well.

Do you think it is necessary to reprogram (remap?) the gearbox at LEXUS dealer? Do I have to buy the gearbox ECU that goes with the used gearbox or has nothing to do with it?

Peter P18 · May 18, 2018

Hey Etienne,

I would imagine the car and the new gearbox would need to be paired up for things to work properly, but you shouldn't have to buy the gearbox ECU from the donor car in my opinion.....

The fact you can generate a CEL from not screwing the petrol filler cap on properly does make me wonder though......

I'd look towards the US forum for some more definitive advice, think they have had a few gearbox swaps due to heavy use with drag racing etc.

Hope you can get it figured out soon.

Cheers,

Pete

Martin F · May 21, 2018

It sounds like something is more fundamentally wrong than a pairing of the gearbox and ECU if you have so many issues.

Do you have a list of the fault codes?

I'm assuming the fluid level has been checked after moving the shifter through all the gears as well.

Connor · May 21, 2018

my isf suffered the same problem a few months ago .gear box is trashed .been to hell and back with Lexus . There not Interested in the way it happened and that the part that failed inside the main radiator caused the gear box fluid to go into the main rad and out through the header ,