Check your water pump. Mine was leaking from same area and it turned out to be the water pump.
DIY Coolant Valley Leak Repair
- Thread starter jmanscotch
- Start date
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Check your water pump. Mine was leaking from same area and it turned out to be the water pump.
Mine had the obvious valley leak and I had the water pump, timing belt and PCV valve all changed when the leak was being addressed.
Doing all that work, did it fix the leak? Or did you have to do the entire "valley leak" repair?
Sorry. Didn’t mean to confuse anyone. I had the valley leak fixed because mine was obviously leaking. I did the wp, tb and PCV as preventative maintenance since they already had the engine bay in pieces. 
have any of you had your knock sensors fail or needed to be replaced because they were submerged in coolant?
I’m having the work done by an independent mechanic and he removed them so they could dry and will test them with an ohmmeter to ensure that they are still working.
i’ll have an answer from him tomorrow.
I’m having the work done by an independent mechanic and he removed them so they could dry and will test them with an ohmmeter to ensure that they are still working.
i’ll have an answer from him tomorrow.
- Thread starter
- #66
I believe my knock sensors looked pretty well sealed (aka I’m talking water proof), I wouldn’t think coolant would get inside them unless they’re damaged (or I am mistaken on how well sealed they were).
- Thread starter
- #67
I was thinking about it again and wanted to share a follow up thought. The sensor being submerged and getting “soaked” is not the only way they could fail due to a coolant leak there.
Coolant becomes more electrically conductive with age, so the idea that the knock sensor connections could get submerged and cause an electrolytic electrical short across the connection terminals is plausible. Assuming the knock sensors would be highly sensitive to even a low amperage electrical short, it seems logical to think that could ruin them pretty quickly.
I wouldn’t think it’s likely the coolant would pool up that high in the valley, to reach the connectors, but maybe.
Coolant becomes more electrically conductive with age, so the idea that the knock sensor connections could get submerged and cause an electrolytic electrical short across the connection terminals is plausible. Assuming the knock sensors would be highly sensitive to even a low amperage electrical short, it seems logical to think that could ruin them pretty quickly.
I wouldn’t think it’s likely the coolant would pool up that high in the valley, to reach the connectors, but maybe.
Acrad
GOLD Star
FSM lists this ohm test for the knock sensors
they passed the test, coolant valley leak repaired. my only issue is he used "blue mountain" coolant, because 'its less sulfuric' and reused the upper and lower radiator hose.
these are all the things that were replaced, and a snap during repair.
Just a heads up for anyone purchasing one of these GX's new or a few years old. Do yourself a big favor and add a few bottles of Red Line WaterWetter to your cooling system. My last truck got over 275K out of original radiator and hoses and I sold it with over 300K and same water pump. Both 22+ year old Lexus's: One with same radiator and hoses and just replaced the other ones radiator along with timing belt kit.
I also recommend doing coolant flushes bi-annually regardless of miles or corrosion/boiling point shown in test. Every coolant leak or heater core failure I have encountered over the years is due to lack of maintaining the cooling system.
You want to flush with white vinegar and hose water. You then simply fill half and half with a mix of coolant and deionized or distilled water. Steer clear of those 50/50 solutions sold at the auto parts stores. Most all 50/50 solutions you buy are mixed with hard water that is not good for the cooling system.
If you purchase used 5 years or more old or over 100,000 miles you are rolling the dice if the cooling system was not serviced. Damage has already started and no amount of flushing is going to do much good. You still want to keep up with the cooling service though to minimize the damage.
Also make sure you are using the block drain to get out the residual coolant left behind. I'm not familiar with the 1UR-FE engine but I imagine it has at least 1 block drain.
I also recommend doing coolant flushes bi-annually regardless of miles or corrosion/boiling point shown in test. Every coolant leak or heater core failure I have encountered over the years is due to lack of maintaining the cooling system.
You want to flush with white vinegar and hose water. You then simply fill half and half with a mix of coolant and deionized or distilled water. Steer clear of those 50/50 solutions sold at the auto parts stores. Most all 50/50 solutions you buy are mixed with hard water that is not good for the cooling system.
If you purchase used 5 years or more old or over 100,000 miles you are rolling the dice if the cooling system was not serviced. Damage has already started and no amount of flushing is going to do much good. You still want to keep up with the cooling service though to minimize the damage.
Also make sure you are using the block drain to get out the residual coolant left behind. I'm not familiar with the 1UR-FE engine but I imagine it has at least 1 block drain.
Trying to figure out if this coolant leak is caused by the valley plate. From underneath I see a lot of pink coolant on this part, does not seem to be replaced in the above write up?
What is this? (Taken from below looking up)The water pump?
In the second image, from above you can see pink splatter on the engine, is that the valley seal area? Seems to be farther towards the passenger, I can’t tell if the first picture is just spraying it over, or vise versus?
What is this? (Taken from below looking up)The water pump?
In the second image, from above you can see pink splatter on the engine, is that the valley seal area? Seems to be farther towards the passenger, I can’t tell if the first picture is just spraying it over, or vise versus?
Think I figured it out, it’s the thermostat!
Anyone’s opinion as to if it’s just the hose or maybe replace the whole thing? Supposedly the WP was done by the previous owner..
Anyone’s opinion as to if it’s just the hose or maybe replace the whole thing? Supposedly the WP was done by the previous owner..
How fresh is that coolant? Is it all dried up?
If it's dry and you're not seeing any drop in your coolant over flow tank, then I probably wouldn't worry about it.
Albeit, it still wouldn't hurt to do a quick inspection on all your hoses and around the thermostat.
Yeah that doesn't look like the valley leak to me.
It may be leaking at the thermostat housing rather than the hose too. Removing, cleaning and resealing and/or replacing gasket may just fix it.
It may be leaking at the thermostat housing rather than the hose too. Removing, cleaning and resealing and/or replacing gasket may just fix it.
There is fresh coolant around, and dried. The rate at which I need to top off the reservoir is increasing. Definitly want to address this before winter.
Seems that the housing doesn’t get replaced so maybe it is a seal, or one of the hoses. As you say.
I found this YouTube video, pretty comprehensive. Haven’t downloaded his files yet, but I love that he made them. Wonder how much the subscription is? Or if one could find a cracked version with the key code..
Figured I should update, leak ended up being just two hoses around the thermostat, one new hose installed and clamp, one just shortened down and new clamp.
My thought is the person who changed the WP and thermostat last used a screwdriver or meat hook to slide the hoses off as the punctures were down at the clamp.
So far no more leaks! Was a best case scanario fix.
Acrad
GOLD Star
Good video but all of that FSM documentation is in this thread. You don't need a TIS subscription IMO.
forum.ih8mud.com
GX 460 Manuals
forum.ih8mud.com
For those dreading the infamous wiring harness clips just warm up the engine before you begin. those clips are very sensitive to temp and they become very flexible when warm. I tried to un-do them before starting the job for about 45 min and gave up. today I tried again after running a few errands and got them both undone in about 3 min, i couldn't believe how easy it was after hearing reports about it being the worst part about the job.