PERRYinLA

I don't really want to change my 1992 SC4's coolant, since it still looks fine, but it has not been changed for 7 years and 50K miles, so maybe I should do it soon. Here's a decent generic write up on how to change coolant:
http://www.peakantifreeze.com/whychange2.html
I'm wondering if anyone has any specific instructions / tips on how to flush and fill the SC4. I did a search and I found some advice from VQT in thread: https://www.clublexus.com/forums/sho...threadid=14144 :
===========Q=U=O=T=E=============
A) Open the cap of the reservoir (be careful when hot)
B) Loosen the plug (nut) on top of the thermostat, that's the filler plug.
C) Loosen three plugs, one on the bottom of radiator, two from the enigine block (one near the filler plug, the other located on the driver side (left side) in the middle of the and lower half of the engine.
Flush the coolant
Torque of the release plugs 13 ft-lbs (engine), the one at the radiator is hand tight. Install the three plugs, fill coolant at the filler plug (the one on top of thermostat; tight the plug with new gasket, filler plug torque 33 ft-lbf. Be careful this engine is aluminum.
Fill the coolant at the filler plug first, then at the reservoir.
====E=N=D===O=F===Q=U=O=T=E======

Here are my questions:
The Peak web page doesn't discuss removing any drain plugs except for the radiator's, but I'm assuming the SC4's radiator does not have one, correct?
Is it feasible to remove the large hoses going to the radiator and draining from there rather than using the engine's drain plugs?
I have one of those T-type fittings that you can splice into the cooling system and connect to a garden hose for flushing- are those of any use here and if so, where do you install it?
How much coolant does the SC4 take?

Thanks in advance for any additional information anyone provides.

VQT

The SC does hs the radiator drain plug. Its locate near the middle of the bottom of the radiator. You have to take the bottom panel out to get acess to the drain plug. I didn't used the drain plug on the side of the engine at all.

You should change the coolant every 30K miles or 2 yrs which ever come first. I think it deal with the coolant characteristic break down. This is a DIY to cut cost, beside the dealer or garage will not use distilled water. Distilled water only mean that the water doesn't have any iron or mineral that could rust out the internal of the engine. This way the radiator last longer too. I don't know there is any true to this, but since 2 gallons of distilled water is not going to kill me if I paid 20 times that for a F*&^ing gallons for Toyota antifreeze .

PERRYinLA

Well, that was no fun at all. I spent most of today "flushing", and I'm still not done. On my SC the drain petcock is on the driver's side of the radiator, towards the rear. It drained so slow, I just yanked off the large hose that runs from the thermostat to the bottom of the radiator, passenger side. That drains fast, but have the drain pan ready and wear old clothes!

Not all of it comes out- maybe 7 or 8 liters. You can get a bit more out by shoving a tight-fitting hose into the thermostat plug (and later on, the overflow tank plug) and then applying pressurized air (or blowing into it).

Then you refill it with water, warm up the engine w/heater on, and drain all over again. I did this 3 times, but the drain water is still far from clear. So I'll do it a few more times tommorrow morning.

As a do-it-yourselfer, I find it very annoying that both the cooling and transmission fluids are not fully "drainable". They could have made it easier.

VQT

Yes its drain slow and it doesn't drain all. You don't have to keep draining it until the water is clear. 3 or 4 times with water is enough. Did you use distilled water? Pull the radiator bottom hose is more work...just have to be patient.
The dealer or garage only drain the radiator fluid and then re-fill it with new coolant and tap water and they charge a lot of money for it. For the DIY, you can flush the water inside the engine by flushing it 3/4 times like you did

gebo

I noticed that it was only after I opened the drain ***** on both sides of the engine block was I able to refill my coolant system with the amount of coolant the manual said it would hold.

I just figured this out last month. Before I was only unhooking hoses and opening the radiator drain ****. I would mix up the appropriate amount of 50:50 and I always had a few quarts left over. That engine block will hold some coolant that you can't get out without using the engine drain *****. Maybe that's why they went to the extra expense of putting 2 drain ***** on the block???? THis is my cut down of me. No offense

Oh,yeah, make sure the heater is turned on hottest setting.

PERRYinLA

I wish I had found those engine block plugs, but I didn't see any on my V8, or at least, any that were easily accessible. Anyway I finished off the flush job today- I did it about 6 times before I was comfortable with the clarity of the water- it looked like very weak tea, or a dirty martini by then. Gawd knows how many flushes it would take to make it REALLY clear.

I had a large supply of pacific rainwater- the same water I use for my indoor plants, so I used that except for the last flush, which was about 1.1 gallons of distilled water.

Each time, I could only drain about 4.75 liters, less than half the 11 liter capacity. I knew I needed to drain a bit more before I could add the coolant to make at least the required 50/50 mix.

Finally, I figured out how- I took a shop vac and inserted the hose into the blower outlet. Then I took a rag and wrapped it around the top filler plug (above the thermostat, center of engine). The rag allowed me to make an airtight seal with the hose and the blower easily blew out another 1.5 liters or so of flushant (!).

I'm glad I used that long-life Dex-Cool, so I don' t have to deal with that again for another 5 years!

Hermosa

You can drain the tranny but be very careful. You can bleed out the fluid by slowly letting the fluid drain out when you turn on the car in the shop. The fluid will slowly drain when the TC is engaged. This is not really a DIY. Mine will undergo this treatment next week when the tranny cooler goes on and the stock one is bypassed.

PERRYinLA

I'm familiar with that procedure (more of a "flush", rather than a "drain"), but what I was referring to is the lack of a drain plug on the torque converter (like the Mercedes has, for example) that would allow almost all of the ATF to drain out without resorting to the flush method.

I realize it's the best option available to us, but I question if the "flush" method really removes all the ATF as well as a "drain" method would (if our torque converters had a drain plug). The fresh ATF enters the top of a pool of old ATF, and at the bottom of the old ATF is the intake for the pump, which flushes out the old fluid. There's a bit of commingling going on there in that top layer before it gets down to the bottom.

Yes, most of the old ATF will come out, but not all, at least not without going through a lot of expensive ATF. It is similar to changing your engine oil by tapping into the sump pump. That would not give you a very thorough oil change for the very same reason, and everyone would still use the good ol' drain plug.

Hermosa

The method I was talking of does not involve adding fluid until the converter is drained. This is why I do not advise it as a DIY. If you get happy with the accelerator you can fry the TC. The fluid will drain out and then you add fluid back in when it empty.

rykwebb

Dont suppose this is the same operation for a 92 SC300? If so, great, if not could you re-route me?

PERRYinLA

It is similar.
The capacities may be slightly different, and the engine drain plugs are in different locations, of course.
But the basic procedures are the same for most cars, not just the two SC models.

Slackful

Hey I'm doing my first radiator replacement for my 95 SC4. So once I drain the engine *****, would I have to flush out the cooling after I replace the upper & lower hosing and radiator? I bought the same Toyota RED as well. The radiator is corroded thats why I'm replacing it.