Coolant leak - but where is it coming from??

I have a 2015 5.7L supercharged Tundra. I noticed just a few of small drops of antifreeze on the garage floor and the coolant overflow reservoir was low. I checked the radiator which was full and also the intercooler reservoir for the supercharger which was was also full. So it would appear to be a slow leak which is causing the overflow reservoir to have to be topped off occasionally. But when I got under the truck I noticed quite a bit of dried up coolant on the passenger side of the vehicle apparently dripping down from someplace up top. I can't see anything obvious from topside. I checked the hoses I could see and nothing leaking from there. Please see the attached picture which shows dried up coolant collecting and building up along the side of the transmission bell housing and dripping on some the lower coolant lines (I think these are for the transmission cooler). But those are not leaking at their clamp locations. I appears to be dripping up from above, but I can't see or tell where from. Any help or ideas of what this might be or where it could be coming from would be appreciated, so I know what I'm dealing with before going to the dealership or trying to fix it myself. Thanks!!

 

I have this EXACT same issue with my 07!

Did you end up figuring out what it was?

 

Pressure test the system see if it showes its face .

 

I checked it again and there is nothing I can see topside. If I get underneath the car that when I can see dried up coolant collecting on the lower part of the engine. I sprayed off all the dried up coolant with a water hose and again could not see anything obvious with both the car off and also with it running. I refilled the plastic overfill reservoir. The radiator was full and the supercharger reservoir was also full. After some time I again noticed some drips on the garage floor. Coolant reservoir was low again. This is a very slow leak and I can't seem to isolate it or where it is coming from. That is why I posted the pictures before, hoping someone else would have experienced this and would chime in. I was hoping by showing the general area with the pictures that someone would be able to tell where it might be coming from ... a gasket maybe. Like I said I can't see any obvious hoses leaking or hose clamps needing tightening.

 

The real only way to find a leak like that is a pressure test. You can rent them from the auto parts store. Take it back and get your money back. If you can air up a bike tire and put on the radiator cap you can use a pressure tester.

 

If it was me I would be looking at those lines look like coolant is getting past that clamp.

 

Like Vince said, pressure test would be the easiest way to find it. I would guess it is probably those cooler lines. They may have been rubbing against something and have a small hole that will only keep getting worse. Could be the clamp at the top where it transitions back to a rubber line.

 

Underside of the intake is a coolant manifold of sorts that can leak and dribble down right there.

 

That is exactly what happened to my Tundra. There is a coolant valley that runs under the intake manifold that is only sealed with silicone. Toyota had to reseal mine 3 times and replaced the heat exchanger to fix it. The shop foreman said if it didn’t hold pressure on the 3rd attempt they would have had to replace my engine block. Thank god for warranty or it would have cost $3600 to fix. Also, @ronrich do not overfill the coolant container. The levels rise when the engine warms up. It should be between high and low in the container.

 

Wow thanks for the replies especially the one with pictures. That looks very similar to what I'm seeing. I wasn't aware of that coolant valley with silicone sealant. I wonder now if Toyota didn't do something just right when the supercharger was installed. I bought the truck at a dealership and it already had the supercharger. Records show it was installed by a dealership in Calif by the previous owner. Seems awfully suspicious now with comparable pictures. I bought an extended warranty from Toyota since the truck only had roughly 13k miles at the time. Now at 43k, this ought to be an interesting experience when I bring it in to the dealership. Thanks again for the help! And yes I do not overfill the plastic reservoir always between the marks.

 

Mine was dripping down the bell housing. I could not see anything from the top of the engine. Glad you got the extended warranty. Toyota had my truck for about a week and a half to get it fixed. Hopefully this video uploads correctly. This will explain what my issue was and possibly yours @ronrich .

https://youtu.be/PnUL0GR6mfs

 

Thank you sir, that explains a bunch and has been a major help! Mine is also not visible from the top and was also dripping along the bell housing. Sounds like this is the problem. What concerns me is they are going to have to pull off the supercharger to get to all that. Sounds like a major job. According to all the paperwork I have this should be covered under the extended warranty. I just hope the dealership doesn't make this difficult and a hassle. I'm curious of you opinion in dealing with the dealership, should I tell them where I think the problem is and reference these forum discussions or just tell them it is leaking?

 

Yes. The supercharger will have to come off. If that’s where your leak is coming from. I would not tell them where you think it is coming from. My dealership really did care to much of what I thought. I would just tell them it’s leaking and to fix it. If they start giving you issues I would refer to the discussions and videos from the forum. They did provide me with a loaner car (4Runner) for the week or so they had my truck.

 

https://www.tundras.com/threads/what-the-heck-is-this.105443/

Here is the thread I created when my truck was leaking for your reference. I will try and update it to let everyone know the outcome. Good luck again and let me know if I can help in anyway.

 

I appreciate your input and advice. I kind of get the same feeling when I go to the dealership. Hopefully this goes smoothly, I guess I'll see when I bring it in.

 

I thought I'd provide an update to again extent my thanks and appreciation to y'all and especially TwistedTad for providing the help. Maybe this write-up and experience will help someone else. Prior to going to the dealership I again monitored the truck for a week. It was still leaking but very slowly and hardly noticeable because most of the coolant dries up on the engine, along the transmission bell housing, and maybe a drop or two makes it to the garage floor. I took pictures from underneath the truck. I scheduled a Monday appointment (5/30) with the dealership and brought it in at 8:00 AM. I told the service advisor that I had a very slow coolant leak that couldn't be seen from topside but only from underneath the truck. I told him I had checked all the obvious hoses and places and it was not coming from there. I hinted at the coolant valley and he stated, "I have only seen two of those in the ten years working at the dealership". Implying it doesn't show up much on these Tundras. He tells me there is a $165.00 diagnostic fee just to look at the truck. I showed him my extended warranty documentation and he quizzed me as to where I purchased it. Leaving the dealership he stated they would have to figure out where it is leaking from first before contacting Toyota warranty. I get a call late Monday telling me I would have to approve another $900.00 fee to pull the supercharger because they still can't tell where it is coming from. When I pushed back and mentioned the coolant valley and the fact it was a very slow leak along with the obvious drip locations on and forward of the bell housing, he responded it could be the bypass hoses behind the supercharger, the bypass plate, or the coolant valley. He said they think it is dripping down near the firewall. So now I'm obviously "sitting on pins and needles" wondering if this is or is not going to be covered by the warranty. The next day late that afternoon I get a text from the service advisor "leaking from the heat exchanger under the supercharger, I'm on the phone with warranty company now". We talk on the phone later that day and he tells me everything is covered under the warranty and said it was also leaking from the thermostat. I picked up the truck Thursday morning and he tells me they pressure checked and drove the truck 6 miles that morning along with reviews from their senior head technicians and that everything is fixed and I'm good to go! I drive the truck no more than 10 miles and both the check engine light and "No Traction Control error message come on. I drive the truck right back to the dealership and wait around for an hour before I convince him to put me back into a rental car because I can't wait around all day. Especially since when I went back to the truck to get my belongings I noticed two techs over the engine bay with the fuel rail removed. No telling what is going on or how long it will take. Get a text later that afternoon that it had a warped injector cushion which let air in that was causing the errors. I picked up the truck later that afternoon on Thursday. So I guess getting that extended warranty definitely paid off. It paid for itself and then some. So far no more error lights and no leaks! So hopefully this is now fixed with no more issues.

 

Glad to hear everything worked out @ronrich !!!

 

That coolant valley is one of Toyota's dumbest designs along with the old 4.7 starter in the valley. I wish someone would come out with a nice sealing gasket to replace the FIPG seal.