Transmission fluid in coolant
02-02-15, 11:15 AM
#1
Driver School Candidate
Thread Starter
Join Date: Jan 2014
Location: Ca
Posts: 10
Likes: 0
Received 0 Likes
on
0 Posts
Transmission fluid in coolant
I have a 1997 LS400. It has been running strong since the timing belt problems last year:
https://www.clublexus.com/forums/ls4...ped-teeth.html
When I repaired the timing belt, I replaced the radiator because it blew the bottom seal when it overheated. My son drove the car 13,000 miles across the country last summer without any problems.
Last week, the car overheated again, and I noticed the thermostat housing was cracked and the coolant was very low. I replaced the housing and filled the system with green coolant (I know that is a no-no). I idled the car to bring it to normal temp, and when the thermostat opened, I noticed the coolant in the reservoir changed color to light red and did not smell like coolant. Also, the transmission fluid was obviously diluted from the pink color (I use type-IV).
I am looking for recommendations on how to proceed with flushing both coolant and transmission systems. Also, should I switch to an external tranny cooler? I don't remember which radiator I installed, so I could also use a recommendation for a good one.
Thanks,
Bob
https://www.clublexus.com/forums/ls4...ped-teeth.html
When I repaired the timing belt, I replaced the radiator because it blew the bottom seal when it overheated. My son drove the car 13,000 miles across the country last summer without any problems.
Last week, the car overheated again, and I noticed the thermostat housing was cracked and the coolant was very low. I replaced the housing and filled the system with green coolant (I know that is a no-no). I idled the car to bring it to normal temp, and when the thermostat opened, I noticed the coolant in the reservoir changed color to light red and did not smell like coolant. Also, the transmission fluid was obviously diluted from the pink color (I use type-IV).
I am looking for recommendations on how to proceed with flushing both coolant and transmission systems. Also, should I switch to an external tranny cooler? I don't remember which radiator I installed, so I could also use a recommendation for a good one.
Thanks,
Bob
02-02-15, 12:30 PM
#2
Sorry to hear about your problems. If it were me, I'd:
0. Try to figure out why it overheated twice. If it's due to low coolant, find the leak and fix it. If something else, find it and fix it or you may be here again.
1. Disconnect the ATF cooler lines going to the radiator and connect them to eachother, bypassing the radiator/AT oil cooler and isolating the two systems. Assuming that the failure point here is the interface between the AT Oil cooler and the coolant part of the radiator, you should expect to have coolant leaking out of the AT Oil cooler connections. No problem because the next step is to ...
2. Drain / flush / rinse the coolant thoroughly, using Prestone flush or whatever. BTW on the red vs. green fluid ... when I first got my '91, I asked the dealer on red vs. green and they said it does not matter. I've heard many stories of people swearing by the red stuff and saying your car might explode if you use the green. But I have not heard of any cars exploding due to the green, and researching it myself - Ethylene Glycol vs. Propylene Glycol - seems like green should be fine as long as any red is all flushed out. I've used green since then with no problems.
3. replace the radiator with the highest quality I could find. OE would be a good candidate to consider here.
I would not put in an external ATF cooler. As far as I know, the OE system works fine unless something else went wrong.
So now hopefully your cooling system is OK after step 3. Still keep it isolated during the next step.
4. Flushing the junk out of the AT system will be tougher. Of course start with a drain, remove/clean pan + replace filter. Let it sit for a while with the front jacked up and more ATF will come out. Then this is a case where I'd probably do the non-powered continuous flush, where you open the system at the ATF cooler line and fill new stuff at the dipstick while the old is pumped out. Even though your system will be more contaminated than most, I would not recommend a powered flush - too many stories about AT failure after that.
5. Once the AT system is fully flushed, re-connect the AT oil cooler connections at the radiator.
6. You're probably then due for more-frequent regular drain and fills after that.
Thankfully I'm not in this situation, but if I were, this is what I'd do, and I would not worry too much about it. But I _would_ try to figure out why it has overheated twice. Something is wrong there.
0. Try to figure out why it overheated twice. If it's due to low coolant, find the leak and fix it. If something else, find it and fix it or you may be here again.
1. Disconnect the ATF cooler lines going to the radiator and connect them to eachother, bypassing the radiator/AT oil cooler and isolating the two systems. Assuming that the failure point here is the interface between the AT Oil cooler and the coolant part of the radiator, you should expect to have coolant leaking out of the AT Oil cooler connections. No problem because the next step is to ...
2. Drain / flush / rinse the coolant thoroughly, using Prestone flush or whatever. BTW on the red vs. green fluid ... when I first got my '91, I asked the dealer on red vs. green and they said it does not matter. I've heard many stories of people swearing by the red stuff and saying your car might explode if you use the green. But I have not heard of any cars exploding due to the green, and researching it myself - Ethylene Glycol vs. Propylene Glycol - seems like green should be fine as long as any red is all flushed out. I've used green since then with no problems.
3. replace the radiator with the highest quality I could find. OE would be a good candidate to consider here.
I would not put in an external ATF cooler. As far as I know, the OE system works fine unless something else went wrong.
So now hopefully your cooling system is OK after step 3. Still keep it isolated during the next step.
4. Flushing the junk out of the AT system will be tougher. Of course start with a drain, remove/clean pan + replace filter. Let it sit for a while with the front jacked up and more ATF will come out. Then this is a case where I'd probably do the non-powered continuous flush, where you open the system at the ATF cooler line and fill new stuff at the dipstick while the old is pumped out. Even though your system will be more contaminated than most, I would not recommend a powered flush - too many stories about AT failure after that.
5. Once the AT system is fully flushed, re-connect the AT oil cooler connections at the radiator.
6. You're probably then due for more-frequent regular drain and fills after that.
Thankfully I'm not in this situation, but if I were, this is what I'd do, and I would not worry too much about it. But I _would_ try to figure out why it has overheated twice. Something is wrong there.
Last edited by oldskewel; 02-02-15 at 12:36 PM.
02-02-15, 06:02 PM
#3
the cracked t-stat housing and a lack of coolant will obviously overheat the car. that's your main problem which i'm glad is fixed.
OEM toyota coolant is red just like the ATF so you might be getting confused about the mixing of both. i can see the radiator breaking somewhere allowing them to mix but that is highly unlikely esp since you recently replaced it. what is likely is that you had some residual red coolant still in the block/wp and mixed turning your green coolant into light red.
of course ATF is an oil where it would separate if mixed with coolant. if there is truly a mix happening, you should see some separation of the two in the reservoir (might be hard to tell without removing it from the car).
there is no need for an external tranny cooler outside of the factory cooler built into the radiator.
a tranny fuid flush is not really recommended around here. most like drain and fills at every oil change (2 quarts at a time). our trannies get shocked when too much fresh fluid is introduced at once. you can read more on there in the various threads but if you are still curious what it takes to do a flush:
http://www.lexls.com/tutorials/trans...ransflush.html
OEM toyota coolant is red just like the ATF so you might be getting confused about the mixing of both. i can see the radiator breaking somewhere allowing them to mix but that is highly unlikely esp since you recently replaced it. what is likely is that you had some residual red coolant still in the block/wp and mixed turning your green coolant into light red.
of course ATF is an oil where it would separate if mixed with coolant. if there is truly a mix happening, you should see some separation of the two in the reservoir (might be hard to tell without removing it from the car).
there is no need for an external tranny cooler outside of the factory cooler built into the radiator.
a tranny fuid flush is not really recommended around here. most like drain and fills at every oil change (2 quarts at a time). our trannies get shocked when too much fresh fluid is introduced at once. you can read more on there in the various threads but if you are still curious what it takes to do a flush:
http://www.lexls.com/tutorials/trans...ransflush.html
Thread
Thread Starter
Forum
Replies
Last Post
Helius
ES - 1st to 4th Gen (1990-2006)
5
08-23-18 09:26 PM
Johnhav430
LS - 3rd Gen (2001-2006)
17
10-26-17 11:58 AM