DIY Coolant Valley Leak Repair (4 Viewers)

[jmanscotch]

Looks like I may have found the culprit of my strange low coolant condition. Though I haven’t crawled under it yet. What is odd is my tech didn’t find it when he did the multipoint inspection if it does exist.

Would there be any puddles on the ground with this leak? I ask because I don’t have anything that leaks/drips on the ground. And last time I saw underneath the truck it was dry.

I hope this isn’t it for your sake.

I didn’t have any puddles underneath, but did notice some spots of drips as it got pretty bad.

The main thing that gave it away was that I’d smell coolant when going uphill (like off-road incline uphill). I believe the coolant pooled up on the block and would run down the back of the block when going up the incline and I’d have that smell permeate into the cabin. That lead me to check the coolant more often and notice it was repeatedly low, then it lead me under the rig where I noticed the coolant stains running down the sides of the transmission bell housing.

That’s where I’d look: back of the engine and top front of the bell housing.

You can get small peeks at the top of the valley pan edges, but it’s tight with the intake manifold there.

 

[Bang Bang]

Looks like I may have found the culprit of my strange low coolant condition. Though I haven’t crawled under it yet. What is odd is my tech didn’t find it when he did the multipoint inspection if it does exist.

Would there be any puddles on the ground with this leak? I ask because I don’t have anything that leaks/drips on the ground. And last time I saw underneath the truck it was dry.

I didn’t have any drips / puddles on the ground either. I had climbed under the truck for something and saw pink residue everywhere and wet edges of the stock skid.

 

[alefer5]

Looks like I may have found the culprit of my strange low coolant condition. Though I haven’t crawled under it yet. What is odd is my tech didn’t find it when he did the multipoint inspection if it does exist.

Would there be any puddles on the ground with this leak? I ask because I don’t have anything that leaks/drips on the ground. And last time I saw underneath the truck it was dry.

From what I’ve seen online, most of the folks that have a coolant valley leak have fluid leaking down the back of the transmission housing.

However after recently pulling my intake out to inspect the valley plate (I also had a suscpicious coolant leak), I could see that if it was minor, you probably wouldn’t have coolant dripping on the ground, since there are lots of books and crannies.

So with that, how much coolant are you loosing?

For me, my culprit was a cracked / pitted thermostat housing.

 

[MrTorgue]

I hope this isn’t it for your sake.

I didn’t have any puddles underneath, but did notice some spots of drips as it got pretty bad.

The main thing that gave it away was that I’d smell coolant when going uphill (like off-road incline uphill). I believe the coolant pooled up on the block and would run down the back of the block when going up the incline and I’d have that smell permeate into the cabin. That lead me to check the coolant more often and notice it was repeatedly low, then it lead me under the rig where I noticed the coolant stains running down the sides of the transmission bell housing.

That’s where I’d look: back of the engine and top front of the bell housing.

You can get small peeks at the top of the valley pan edges, but it’s tight with the intake manifold there.

Can you show me a picture exactly where to look up top if you can?

I didn’t have any drips / puddles on the ground either. I had climbed under the truck for something and saw pink residue everywhere and wet edges of the stock skid.

Not only is my trans dry there is zero pink crusty stuff anywhere.

From what I’ve seen online, most of the folks that have a coolant valley leak have fluid leaking down the back of the transmission housing.

However after recently pulling my intake out to inspect the valley plate (I also had a suscpicious coolant leak), I could see that if it was minor, you probably wouldn’t have coolant dripping on the ground, since there are lots of books and crannies.

So with that, how much coolant are you loosing?

For me, my culprit was a cracked / pitted thermostat housing.

I’ve lost from F to L on the coolant tank since mid-July but I do not know if that was during the whole time or recently. I filled it up again just now so I’ll check weekly.

 

[alefer5]

Can you show me a picture exactly where to look up top if you can?



Not only is my trans dry there is zero pink crusty stuff anywhere.



I’ve lost from F to L on the coolant tank since mid-July but I do not know if that was during the whole time or recently. I filled it up again just now so I’ll check weekly.

Might be worth looking at your oil dipstick to see if there is any milky color in your oil. Hopefully that’s not the case.

I found that a few of my coolant leaks were phantom. When the pink stuff leaks it gets crusty and it stops the leak. Although a visual inspection of your engine bay is a good way to look for the leak, there are dozens of connections under your intake and behind the block that you’ll never see without removing parts. Plus, if it’s a small leak (which it sounds like yours may be), the hot engine components will flash off the coolant when it makes contact with those surfaces.

I’d spend the $47 for this pressure test kit, and it’ll be dead obvious if and where your leak is. That way you can check for the leak without working around the hot components, yet simulating the correct operating pressure. I’ve used this exact item in the past and can’t say good enough things about it.

Mityvac MV4560 Automotive Radiator/Cooling System Pressure Test Kit, Contains Adapters to Test Most U.S. and Asian Cars, Light Trucks and European Vehicles Amazon product ASIN B003V9L05G

 

[xychromosome]

Can you show me a picture exactly where to look up top if you can?



Not only is my trans dry there is zero pink crusty stuff anywhere.



I’ve lost from F to L on the coolant tank since mid-July but I do not know if that was during the whole time or recently. I filled it up again just now so I’ll check weekly.

See anything at front of engine? Mine was losing some coolant and found that the water pump was failing.

 

[mrshow]

In addition to the valley leak, my rig also had a radiator leak and a hose leak, so its worth checking those. Also check around the water pump area...

 

[MrTorgue]

See anything at front of engine? Mine was losing some coolant and found that the water pump was failing.

Everything is clean and dry. I just had the radiator and all hoses replaced in June 2020. I’m going to do a better visual inspection this week when I have time to pull bunch of stuff off.

 

[Acrad]

A really slow leak can evaporate before draining back on bell housing... IMO... easy to think a very small leak could evaporate from coolant tank loss you describe over 6 -7 months.

You can always try borescope inspection.. pull out some of the foam around PCV and see more

Post #45

Coolant Valley Plate Leak - ClubLexus - Lexus Forum Discussion

GX - 2nd Gen (2010-2023) - Coolant Valley Plate Leak - Does anybody experience coolant valley plate leak for GX460? Dealer told me this is common problem for high mile GX460 engine. I have 2010 GX460 with 93000miles.

www.clublexus.com

PCV Valve

 

[MrTorgue]

A really slow leak can evaporate before draining back on bell housing... IMO... easy to think a very small leak could evaporate from coolant tank loss you describe over 6 -7 months.

You can always try borescope inspection.. pull out some of the foam around PCV and see more

Post #45

Coolant Valley Plate Leak - ClubLexus - Lexus Forum Discussion

GX - 2nd Gen (2010-2023) - Coolant Valley Plate Leak - Does anybody experience coolant valley plate leak for GX460? Dealer told me this is common problem for high mile GX460 engine. I have 2010 GX460 with 93000miles.

www.clublexus.com

PCV Valve

Good stuff thank you.

 

[MrTorgue]

Is there any problem with leaving it like this and keeping on top of refilling coolant? Since I’m buying a new car I won’t driving it much. It doesn’t seem like it’s serious at the moment.

 

[r2m]

Is there any problem with leaving it like this and keeping on top of refilling coolant? Since I’m buying a new car I won’t driving it much. It doesn’t seem like it’s serious at the moment.

Personally, if it's just a very slow drip, I wouldn't worry about it until a hunk of money came in to have someone do the repair. Keep a pan under it so it doesn't ruin your driveway and to monitor how much you're losing. For me, it's nothing I'd like to do at home, nor do I have the physical space to do it, even though I have all the tools and everything necessary, just not the space.

Hoping for your sake (and fingers crossed) it's not serious MrTorgue!

 

[MrTorgue]

Personally, if it's just a very slow drip, I wouldn't worry about it until a hunk of money came in to have someone do the repair. Keep a pan under it so it doesn't ruin your driveway and to monitor how much you're losing. For me, it's nothing I'd like to do at home, nor do I have the physical space to do it, even though I have all the tools and everything necessary, just not the space.

Hoping for your sake (and fingers crossed) it's not serious MrTorgue!

Thankfully my driveway is pristine and my GX doesn’t leak. Underneath is clean and dry.

 

[mcnaughty]

Mines been mysteriously loosing coolant over the past year. ( Total, around 2 litres) For first 8 months, no coolant down the back of the engine. But it was a snowy day yesterday, so I followed the instructions and did the repair.

Great repair instructions.

Three only two issues I had were:

• Electrical harness clips on back of manifold. Just break them off and move on.... It's not worth it!
• The one rear passenger side manifold bolt. I had to undo and move the heater hose to get in there. The perfect tool would probably be a 12mm shallow socket with 1/4" ratchet extension, 6" long.

I had GOBS of dried coolant in there. Wet vac is essential to this repair. Also, I found that brake cleaner did awesome at removing all old fipg.

 

[jmanscotch]

Mines been mysteriously loosing coolant over the past year. ( Total, around 2 litres) For first 8 months, no coolant down the back of the engine. But it was a snowy day yesterday, so I followed the instructions and did the repair.

Great repair instructions.

Three only two issues I had were:

• Electrical harness clips on back of manifold. Just break them off and move on.... It's not worth it!
• The one rear passenger side manifold bolt. I had to undo and move the heater hose to get in there. The perfect tool would probably be a 12mm shallow socket with 1/4" ratchet extension, 6" long.

I had GOBS of dried coolant in there. Wet vac is essential to this repair. Also, I found that brake cleaner did awesome at removing all old fipg.
View attachment 2990790View attachment 2990793View attachment 2990804

It was definitely time on that one, well done.

 

[Acrad]

Good work

I could be wrong but I am pretty sure the front end of your leak could be seen with a borescope

 

[mcnaughty]

Good work

I could be wrong but I am pretty sure the front end of your leak could be seen with a borescope

You're probably right.

 

[jmanscotch]

I never did update this particular thread on what my long cranking issue was, that started immediately after this repair.

Turns out, removing the EGR valve during the repair had disturbed a bit of carbon built up and that carbon junk situated itself in a way that it stuck the EGR valve just slightly open.

With the EGR valve not able to close 100%, the truck would sit after running and exhaust gasses (with some unburnt fuel) would be able to pass back through the EGR valve and accumulate in the intake manifold. After about a hour of that exhaust gas accumulating, if I tried to start the truck, the air mixture in the intake manifold would be rich enough with unburnt exhaust gas fuel that it would be too rich (for what the ECU was expecting) that it’d not have enough oxygen to crank over the engine successfully…for about 7-8 seconds before that fuel rich air was sent through the engine that it got fresh air intake and started.

If I left the GX to sit overnight, it’d start just fine with no long crank as the fuel rich air would dissipate or somehow alleviate itself as an issue.

This was also the slight stumble at idle issue, slightly rich intake air.

Cost me about $2,500 to find this $4 problem (cleaned the EGR valve with carb cleaner and it was able to close 100% and fixed the problem).

Have since fixed the issues permanently by selling the GX (for a heck of a lot more than I payed for it) and buying a new 2021 Tacoma (with a warranty that makes these things not my financial problem).

 

[r2m]

I never did update this particular thread on what my long cranking issue was, that started immediately after this repair.

Turns out, removing the EGR valve during the repair had disturbed a bit of carbon built up and that carbon junk situated itself in a way that it stuck the EGR valve just slightly open.

With the EGR valve not able to close 100%, the truck would sit after running and exhaust gasses (with some unburnt fuel) would be able to pass back through the EGR valve and accumulate in the intake manifold. After about a hour of that exhaust gas accumulating, if I tried to start the truck, the air mixture in the intake manifold would be rich enough with unburnt exhaust gas fuel that it would be too rich (for what the ECU was expecting) that it’d not have enough oxygen to crank over the engine successfully…for about 7-8 seconds before that fuel rich air was sent through the engine that it got fresh air intake and started.

If I left the GX to sit overnight, it’d start just fine with no long crank as the fuel rich air would dissipate or somehow alleviate itself as an issue.

This was also the slight stumble at idle issue, slightly rich intake air.

Cost me about $2,500 to find this $4 problem (cleaned the EGR valve with carb cleaner and it was able to close 100% and fixed the problem).

Have since fixed the issues permanently by selling the GX (for a heck of a lot more than I payed for it) and buying a new 2021 Tacoma (with a warranty that makes these things not my financial problem).

View attachment 2991529

Sorry to see you leave the forum jmanscotch.
But nice truck!

 

[JDUB fab]

Thanks all for contributing to this. I’ve noticed some coolant on the bottom of my engine bay, here is an image of where the drip terminates. Will start to investigate the source. Hoping it’s not the valley leak.. but this thread has given me the confidence to attempt the repair if it is. Haven’t noticed a drop in the coolant reservoir.. yet.