Kind of "Mystery" Coolant leak back of engine (heat exchanger valley leak)

[sdnative]

Pro-tip: Use a wet-vac with a fine tip to suck up all the coolant and any debris that may be laying around the valley.

Also, dip the union pipe orings in coolant to lubricate before installing.

 

[Supra88]

Pro-tip: Use a wet-vac with a fine tip to suck up all the coolant and any debris that may be laying around the valley.

Also, dip the union pipe orings in coolant to lubricate before installing.

I did use the shop vac! Good call on the coolant for lubricant.

if anyone needs orings let me know. I ordered 2 and Toyota sent me a bag of 10!

 

[Supra88]

Does anybody remember where these two smaller foam pieces go? Are they installed after the manifold is in? As opposed to the larger pieces that are installed under the manifold.

 

[bloc]

Does anybody remember where these two smaller foam pieces go? Are they installed after the manifold is in? As opposed to the larger pieces that are installed under the manifold.

View attachment 2489004

They go on the sides of the manifold after it is installed. Top one on the drivers side under the vacuum solenoids that get bolted on top.

 

[Supra88]

They go on the sides of the manifold after it is installed. Top one on the drivers side under the vacuum solenoids that get bolted on top.

Awesome thank you.

 

[mdh384]

Going to chime in with a tip and a question.

For the tip: A 10mm dog bone makes getting the air injection valves out easier, particularly when trying to break loose the two rear bolts.

For the question: What are folks using to remove residual sealant? I have scrubbed with chlorinated brakleen and managed to get most of the chunky stuff off. There is a thin film residue that I cannot seam to get to go. As a corollary; has anyone foregone the $$$ sealant and swapped to the toyota "red" coolant, rather than the SLL "pink" coolant which seems to require the special sealant?

 

[Supra88]

After all that work I would only consider going with the $$$ FIPG. Overall it's really a <$100 fix between the FIPG and orings.

 

[bloc]

After all that work I would only consider going with the $$$ FIPG. Overall it's really a <$100 fix between the FIPG and orings.

This.


And I like to use a thin bristle brass or stainless wire brush to get the last of old RTV off.

 

[mdh384]

As an update - this job has been an exercise in patience.

I initially ordered the (incorrect) sealant, intake manifold gaskets, PCV valve, and some unrelated parts on 12 march, with an ETA of 19 march.. Due to weather in Denver and USPS "issues", that order was delayed and finally arrived today, 1 april. The dealer I ordered from was quite flexible; they sent me the pcv and intake manifold gaskets again via UPS, as it appeared as though the whole original order had been lost. I was able to source the correct sealant via Amazon. The correct sealant, pcv, and gaskets arrived late last week, and I went ahead and installed the cover plate.

Because I am a bit paranoid, I decided to pressure check the repair after reinstalling the coolant crossover pipe at the front of the heads... This turned out to be a good idea, as both sides of the crossover pipe AND the cover plate leaked. While the system would hold 15psi for 5 minutes, it would drop to about 13psi after ~15 minutes, and leaking was visible at the interface of both sides of the crossover pipe and and the rear, passenger side of the cover plate. I have redone the cover plate work, and that is no longer leaking. I am now awaiting the two gaskets for the coolant crossover pipe. The local dealer claims they will be here tomorrow.

I also noted that the knock sensor harness has been partially chewed through; luckily that order arrived in a much more timely manner. I am glad I inspected it upon disassembly after noticing mouse poop underneath the dried up coolant. The passenger side rear knock sensor lead had only 3 strands of the black wire still intact. I hope the mouse died after ingesting the leaking coolant!

 

[anthracite]

Well, mine has been leaking for about a year...slowly (150K miles). It's now dripping and leaving a small puddle of 3-5 drops. Time to fix it. I had already purchased a new radiator, w/p, thermostat and supporting hoses/gaskets as well as serpentine belt, tensioner and idler. Going to order the parts for this and dedicate next weekend to this project. When I'm done it will be good for another 150K miles hopefully. We're never getting rid of this rig. Thankful for everyone that has posted advise on this thread. I also have all of the FSMs to help too. Wish me luck haha.

Steve

 

[Supra88]

Well, mine has been leaking for about a year...slowly (150K miles). It's now dripping and leaving a small puddle of 3-5 drops. Time to fix it. I had already purchased a new radiator, w/p, thermostat and supporting hoses/gaskets as well as serpentine belt, tensioner and idler. Going to order the parts for this and dedicate next weekend to this project. When I'm done it will be good for another 150K miles hopefully. We're never getting rid of this rig. Thankful for everyone that has posted advise on this thread. I also have all of the FSMs to help too. Wish me luck haha.

Steve

Consider doing the fan clutch and fan bracket assembly (Aisin) while you're in there.

 

[anthracite]

Consider doing the fan clutch and fan bracket assembly (Aisin) while you're in there.

Thanks! I'll look into those as I am ordering the parts now.

Steve

 

[BigMF]

So, I think I have this problem but not 100% sure. I thought my water pump was leaking and was starting the job of replacing it as well as all of the other "Cracked Radiator Project" project list (thermostat, fan clutch, belt tensioner, etc.). As I got the belt off, I noticed a ton of crystalized coolant near the top of the front of the engine. The pictures below are taken from the top of the engine with my phone either just above the fan shroud or between the fan and engine.

I didn't know about the valley leak until tonight and had assumed it was the water pump leaking because there was some coolant trailing from that area. However, in retrospect, it may have been dripping from higher up and finding it's way to the area of the pump. Orrrr......I guess it could be both.

It was getting dark when I discovered this (and my wife was getting HANGRY) so I did not have time to take my ARB skid plate off to look at the back of the engine and see if it was dripping there as well. Before I go to all the trouble of taking the air intake manifold, is there any other possibility for where this coolant might be leaking from at the top of the engine? I know I'll probably need to take the manifold off regardless to determine for sure what is happening but I wanted to get a jump on getting the parts I need such as the O-rings and gel made from diamonds (oops, I mean 1282B).

 

[bloc]

So, I think I have this problem but not 100% sure. I thought my water pump was leaking and was starting the job of replacing it as well as all of the other "Cracked Radiator Project" project list (thermostat, fan clutch, belt tensioner, etc.). As I got the belt off, I noticed a ton of crystalized coolant near the top of the front of the engine. The pictures below are taken from the top of the engine with my phone either just above the fan shroud or between the fan and engine.

View attachment 2843377

View attachment 2843376View attachment 2843375


I didn't know about the valley leak until tonight and had assumed it was the water pump leaking because there was some coolant trailing from that area. However, in retrospect, it may have been dripping from higher up and finding it's way to the area of the pump. Orrrr......I guess it could be both.

It was getting dark when I discovered this (and my wife was getting HANGRY) so I did not have time to take my ARB skid plate off to look at the back of the engine and see if it was dripping there as well. Before I go to all the trouble of taking the air intake manifold, is there any other possibility for where this coolant might be leaking from at the top of the engine? I know I'll probably need to take the manifold off regardless to determine for sure what is happening but I wanted to get a jump on getting the parts I need such as the O-rings and gel made from diamonds (oops, I mean 1282B).

The top back of the timing cover has a port in it that the valley plate seals into via a pipe with oring on the end of it. Thing is, even if that leaks, the downhill flow path would be into the valley, not over the front of the timing cover and down to the pump. I guess it’s possible your water pump gasket is leaking too. Usually when the pump itself fails the flow is downward as well as into the back of the pulley where it may get flung out all over the place, but your picture has a lot of concentration in that one spot seemingly above the water pump shaft and weep hole. Seems odd. You need to get those pulleys out and have a better look.

 

[BigMF]

Got the shroud and fan out of the way and am able to get a better view. Here's a short video that hopefully helps pinpoint the issue. Appreciate any thoughts.

 

[bloc]

Got the shroud and fan out of the way and am able to get a better view. Here's a short video that hopefully helps pinpoint the issue. Appreciate any thoughts.

Still not clear to me. You need to get that water pump pulley out of the way.

 

[kms254]

I’ve had an unexplained coolant consumption for a bit and I’m wondering if this is my issue. I’ve done all the normal stuff, radiator, water-pump, thermostat etc.. no water in the oil and no signs of it burning off.

Will this leak show up on a leak down test?

As far as I can see with a mirror and a flashlight by the pvc valve I can’t see any pink.

No noticeable external leaks anywhere else. If I pull the intake manifold to get a better look , do I need new gaskets?

 

[Supra88]

I’ve had an unexplained coolant consumption for a bit and I’m wondering if this is my issue. I’ve done all the normal stuff, radiator, water-pump, thermostat etc.. no water in the oil and no signs of it burning off.

Will this leak show up on a leak down test?

As far as I can see with a mirror and a flashlight by the pvc valve I can’t see any pink.

No noticeable external leaks anywhere else. If I pull the intake manifold to get a better look , do I need new gaskets?

It's most likely the culprit. I had to put a borescope from the back of the manifold to see the pink crust. You do not need new intake gaskets for this job. Two Orings and the proper FIPG.

 

[kms254]

It's most likely the culprit. I had to put a borescope from the back of the manifold to see the pink crust. You do not need new intake gaskets for this job. Two Orings and the proper FIPG.

Borescope happened to be an Amazon lighting deal… should be here by 8am tomorrow!

 

[anthracite]

Well, mine has been leaking for about a year...slowly (150K miles). It's now dripping and leaving a small puddle of 3-5 drops. Time to fix it. I had already purchased a new radiator, w/p, thermostat and supporting hoses/gaskets as well as serpentine belt, tensioner and idler. Going to order the parts for this and dedicate next weekend to this project. When I'm done it will be good for another 150K miles hopefully. We're never getting rid of this rig. Thankful for everyone that has posted advise on this thread. I also have all of the FSMs to help too. Wish me luck haha.

Steve

I started this project and it is an exercise in patience, not due technical reasons but more due to just being a difficult place to work. I have it apart now and will finish up bolting it back together tomorrow. Definitely not an easy project. Just not a lot of room to work abs the Toyota engineers didn’t do us any favors. Mine must have been leaking for a long time. It had about an inch of build up around the entire plate.

This thread has been a huge help. Thanks to all that posted for your help.

Steve