that is such a bummer and I feel really bad for you…the pic looks like motor oil and possibly coming from the left bank or drivers side. Do ya think it’s a valve cover or spark plug gasket?

I also see a hint of red at the top of the towel, PS or Transmission fluid?

 

Crap, I would take a look at all the hoses that were pulled to see they are on tight. Hopefully its an easy fix.

 

Well. I have good news and bad news I think. The knock sensor job has nothing to do with the leak. The top of the engine that I can see with pretty much everything together is still clean.
Now the bad news. And I can't even believe this. The liquid is coolant. The overflow reservoir was empty, but the radiator is full. I haven't positively identified the issue yet. But my guess is that my water pump is going out. I see coolant in the bottom (or top depending on how you look at it), the front engine cover below the water pump but nowhere else.
So, I can look at it as I am the LUCKIEST SC430 owner because I didn't overheat my engine and cause catastrophic damage. Or the unluckiest SC430 owner because the water pump went out 60 miles after doing all of the work for the knock sensors and starter.
All I can say is just WOW. If I confirm that it's not related to the work with the knock sensor, I'll start a new thread. How to change your water pump in the parking lot. It was such a beautiful day here in SanDiego too. 🙄

Paul

 

didn’t you change the timing belt, water pump etc already?

 

Actually no. When I purchased her, she had around 100,646 miles. The previous owner had the TB and water pump changed on 4/17/2019 at 100,592 miles with what the receipt says is an R&I(?) waterpump, then TB Kit, a sensor of which isn't identified on the receipt and a gasket which also isn't identified an air filter and coolant flush. I noticed it had the green coolant and did a flush and fill with Asian Pink at 102,375 miles. This was before I found the forum and knew nothing really about the SC other than it was beautiful and I was immediately in love. 🥰 The previous owner was in Realtor training and concluded very quickly that the SC was not the car she needed for moving clients around. So the only thing I was planning was to do to it all (TB and WP) was at somewhere around 180-190k.
I have to Thank You especially for your mentoring when I found this forum too. Without you and the other moderators, I wouldn't be anywhere as competent as I am now and allowing me to help others in small ways. This car and this forum has brought me great joy. ☺️

Paul

 

did you disconnect the water hose just below the upper radiator hose when you removed the intake?
If so, make sure the clamp is tight and in place.
also, is it possible the hose cracked?

I know they are in the back but check the heater hoses for leaks.too.

 

No Sir I have not. I replaced every hose and replaced every clamp with OEM style spring clamps when I did my first flush. I just considered it "regular maintenance ". And when I did the knock sensors, the heater hoses in the back of the engine (and the crossover at the back) were in my face. Both were still quite pliable and in good shape. I will of course be pulling the engine under covers and cleaning and inspecting everything when I get a moment. It may not be the water pump at all. But until I can do a full inspection, it's my best guess. But nothing is positively identified as a failure just yet. 🤔 And unfortunately, we have rain forecast for the entire week here in SoCal.

Paul

 

it just seems odd that a newer WP would go bad right after other maintenance was performed.
I will keep the positive vibes going for a simple corrective action 😉

 

I agree. It's very odd. Some additional information is that I went out last night to do a quick inspection to see which fluid I might be dealing with and I started the car and let her run up to temp. I saw nothing leaking. I just found the coolant reservoir empty. Oil level is good as well as all other fluids. So, what does that mean? Does the system need to be heated up and under pressure? Is it my thermostat? Maybe. But again, until I can actually see coolant dripping, I just dont know. Strange indeed.

Paul

 

Paul,

Did you check this coolant bypass hose that skinny one that connects to the bottom of the intake manifold:

https://www.toyotapartsdeal.com/oem/...261-50090.html

That could possible leak coolant.

 

If I'm correct, that hose goes to the Throttle body. And yes that hose did get moved around when I pulled the throttle body to remove the intake. I will be checking the entire cooling system to make sure though. The fun has just begun and I should start a new thread to quit cluttering up the knock sensor subject. 😁

Paul

 

Well. We finally got some decent weather before the next storm and I got a chance to look her over. It looks like the waterpump gasket on top failed. I can definately see where the coolant is leaking from. The decision has to be to go ahead and do the TB, Waterpump ahead of schedule. It had 62k miles. I'm so sad. But also relieved that it wasn't much worse by overheating the engine. 🙁 Just bad luck in this case.

Paul

 

Man that stinks. Probably the two worst maintenance things the SC needs and you get hit with both of them in the same month.

 

Paul,

Can I ask which starter motor did you bought. I see a denso starter that fits the sc430 but I noticed the wattage is 1.4kw where as the oem spec is 2.0kw:


https://www.lexuspartsnow.com/parts/...tra2=&filter=()

What do you think? Also, hope you are making progress on the coolant leak!

 

I paid $176.26. You can find them cheaper for sure.
https://www.lexuspartsnow.com/parts/...-50110-84.html And this has a CORE Charge.

P/N 28100-50110-84 Starter Motor

As far as the coolant leak? She is in with Lexus with a blown water pump gasket. Sad. But she'll be better than ever by tomorrow.
Paul