LS4Lexus

I am going to a local shop to have the coolant and ATF on my '91 LS400 (100K miles) drain-and-refilled. I want to use Toyota fluids, so will be dropping by the parts department of the Toyota dealer first. How much fluid of each type do I need to pick up? And do I need any other parts? (drain plug gaskets? Is thermostat changed during each coolant service?)

The thing that confuses me about coolant drain-and-refills is that, from what I've read, there seems to be multiple different places in which the coolant can be drained. And the amount of replacement fluid needed would depend on which place(s) the coolant is let out. Does this apply to the 1st-gen LS400?

Lexusfreak

Well Toyota / Lexus has a new coolant that is Pink in colour.....called Super Long Life engine coolant......it is good for 5 years or 150,000 miles & is already 'pre-mixed' with a 55% coolant & 45% distilled water mixture.......I would get 2 jugs (2 gallons). Your fluid capacities should be in your owners manual. I think u need between 4 - 6 qt's for the 'drain & fill' tranny fluid. Or you can go for the 100% fluid change which is about 15 or so bottles.

LS4Lexus

That isn't compatible with the standard (red) Toyota Long Life coolant though, right?

saber

The factory original coolant mixture was 50% distilled water and 50% Toyota (Red)Long Life Coolant. Continue using this mixture if you don't want to risk compatibility problems.

If your Lexus has always had Toyota Red coolant in it then your cooling system is likely still very clean and therefore simply draining and refilling the radiator is sufficient to recharge the corrosion inhibitors.

Now if another coolant was ever used, things are more complicated. In that case it is necessary to drain the coolant out of both of the engine block drain plugs as well as the radiator..

It is also best to measure the amount of old coolant drained and then purchase the required amount of Toyota coolant and distilled water needed to refill the system with a similar amount of new coolant. Alot of owners get into trouble relying on "fluid capacities" instead of simply measuring the amount drained.

CUMan

Yes, there are block drains (one on each side) and the radiator drain. All of these must be opened to completely remove the old coolant.

According to my 93 LS service manual, a transmission drain and fill would require two quarts of fluid.

Make sure you get the right fluid. My 93 calls for Type II, which is no longer available. Toyota Type IV is its replacement. I don't know whether the 91 LS called for Type II or Dexron.

Lexusfreak

I would call your dealer to ask this question to get the correct answer. Having said that, from what I have been told, you can use the pink Super long life coolant.......but if ALL the old (red) coolant is nor properly drained, you will not get the benefit of a long drain interval & will have to change the coolant at a 2 year or 30,000 mile interval instead of the 5 year or 150,000 time frame. Like I said, call your dealer to varify this. Keep us posted.

LS4Lexus

Thanks, I'll pick up 2qts. of the Type IV. My 91 LS calls for Type II as well, but it has Type IV in there already. I just noticed in the manual that ATF replacement is only listed in the severe service schedule and not the regular service schedule. Interesting...I didn't think ATF could make it 120K+ without a change.

LS4Lexus

Do you know what is considered standard for coolant drain-and-refill service, to only drain the radiator or to drain the coolant out of both engine block drain plugs as well?

I will be picking up the fluid at the local Toyota dealer (which doesn't work on Lexus ) and going to an independent shop, so I will have to have the coolant already purchased when I arrive at the shop. I don't mind overshooting the amount by a gallon so I don't get stuck with too little coolant. If any of you happen to have done a coolant drain-and-refill on a 1st-gen LS400, can you recommend the amount of coolant needed?

CUMan

The total amount of coolant needed for a full drain and refill is 11.4 quarts.

If I were having this done, I would certainly have the engine block drained, along with the radiator. The drains are easy to access if the car is on a lift.

GRAND_LS 4

iTrader: (2)

What you have to realize is that you’re changing only 2 of 9 Quarts. So if I were you, I would drain, refill, drive around for 15mins, then drain and refill and possiblly change filter and gasket the first time around as well (this is what I’m doing).

GRAND_LS 4

iTrader: (2)

I just noticed this, what does your SN mean?

LS4Lexus

My owner's manual lists 11.2 quarts as the coolant capacity. Does this mean you can completely replace the old coolant with a drain-and-refill?

CUMan

Yes, the drain and fill procedure replaces all of the coolant in the system if the block drains and radiator drains are all opened. If you only open the radiator drain, the coolant inside the engine block will not drain and therefore will not be replaced.

kreativ

That's good to know. Is there any point in doing a coolant flush then? I thought one of the main reasons for doing a flush is to remove all of the old fluid that a drain-and-refill couldn't.

CUMan

I would think that the need for a radiator flush would depend upon how the cooling system was maintained in the past. If the coolant has not been replaced on a regular basis, or if the present coolant was mixed using mineral-laden water, a flush would probably remove some of the crud which a simple drain would not remove.

However, if the cooling system has been maintained regularly, I think a drain and fill would be adequate.

Always use distilled or demineralized water when mixing the coolant.