Hissing sound from behind engine and coolant leak

1999 V6 SR5 Prerunner (from Cali)

Yesterday, while I was driving I made a turn, and since I had the window down, I thought someone had a leaking tire or a turbo. I thought, "I hope that wasn't my truck". I put my head out the window to listen for a leaking tire, but didn't hear it. Everything seemed fine until I almost got to where I was going (couple minutes away, and I saw white smoke coming from under the hood. Temperature gauge looked good though, I wasn't overheating, but I was low on coolant (it seems this has been a small issue for quite some time). It sounded like a hose was blowing hot air out of a small hole, even for a few minutes after shutting the truck off.

Not far from home so I got some coolant from the store and decided to let the engine cool between short distances of driving home. It seemed to be getting worse, and I was worried about a hose blowing. Made it home. It was dark so I checked it out today.

As I said, I think this has been a small problem for a while since I would sometimes notice a smell after driving, thought it was the tires going out of alignment... I've even noticed smoke in the cab before. I figured it came in through the vents, thought it was from an oil leak, and I only noticed it once.

Well, anyway this is what I found. What do you call the thing it's leaking from? Any advice? Is it a common problem? Thanks.

 

I went out to inspect it some more... and now I have multiple questions...

That isn't a fuel rail is it?!
If so, can gas burn off the engine as white smoke?
Why don't I smell gas?
Why does it not catch fire?

Wouldn't coolant leave a sticky residue, or maybe not?
I'm so confused.

There is also a rubber hose leaning on it. It goes to near the sensor under the throttle body. Can't tell if it's leaking though. Doesn't seem like it.

Strange thing is seems to make noise as if there's a lot of pressure when the engine heats up, then stops when the engine cools back down. So, that makes me think it has to do with the cooling system.

 

I can't see exactly where the leak would be from your video but I would suspect it is coming from the "rubber hose leaning on it". Probably wore a hole through the hose and is causing a coolant leak under pressure, it will continue to get worse. How much coolant did it take to refill the radiator?

 

Hmm, not a whole lot. I still have a good amount in the bottle.

I had the same thought, and I felt the hose and didn't feel any abrasion. I guess I'll have to put something between them to see if the leak pattern changes.

 

I think I may have found the problem. Thanks for your suggestion.

It seems like this hose (the one that goes right underneath the end of the rail), is worn at the bottom, and must have been shooting a small undetectable stream at the rail, while I was filming.

It's really hard to get a good picture of the damage.

 

Glad you found the problem. I would replace both of those small hoses and maybe the top and bottom radiator hoses. Then fill with fresh antifreeze if I was going to be messing with the cooling system anyways. Your call on the condition of the other hoses as you can see and feel them. Best of luck with it.

 

Thanks!

 

I see the drip at :32.

It's coolant lines to the throttle body to warm it up in cold weather. I would bet ALL your hoses are 20 yrs. old.

 

I think it was this one...


Also have a couple other problems at the moment...



Plus, I creased one of my heater core pipes a bit while trying to get the hose off. Hope it doesn't leak when I put the hose back on.

 

The cost might equal a car payment or two but it will be worth it to get all of these little items repaired. You might put a small amount of silicone sealant on the heater core pipe to help it seal but don't go crazy or you will likely create more problems.