Can't find the source of a coolant leak. Lose about a 1/4" - 1/2" out of the degas bottle per tank of fuel. Ideas?

Everything above these steering linkages looks perfectly dry, and you can't see anything from the topside of the engine compartment either.

These pictures were taken after truck hasn't been started in over a week. I didn't think to start the engine to see if the source of the leak would show itself, but will try that tonight.

 

When my thermostat housing leaked it appeared more on the drivers side. Are you able to see up by the water pump to see if there's a leak around there?

 

I had a mystery leak for a while and it ended up being the heater valve. Everything looked dry but when looking at the valve there was moisture around the philips head screw on the top. I was losing about 1/2 gal. a week from that tiny screw. Another forum member Jayybird brought it to my attention because he had posted a leak in the same spot.
It doesn't explain the drip on your steering stabilizer unless it somehow found a route there.

 

I reached down under the water pump shaft from above as shown in the picture and didn't feel any moisture.



I remembered that thread and checked out my heater valve. It's dry.

There has to be a leak somewhere above the stabilizer, but it's hiding pretty well so far.

It seems like it has to be coming off the front of the engine, since everything that drips in the valley ends up behind the engine under the firewall.

 

Look at the lower radiator hose especially where it comes close to the power steering gearbox. It may have rubbed a hole in it, I have seen a few of these do it. In fact with many of these they will stop leaking or slow down when running, and leak more when you shut it off. This is because of the suction "vacuum" on the lower hose when running.

Please keep us posted on what you figure out.

 

the rule of thumb:
start high from the front and work your way back.

however, why does it look wet like oil?
Degas bottles have the tell-tale dried white residue, so if the trucks' been sitting for a week, shouldn't it have dried white like coolant if it is coolant?
based on the pictures, I see a dampener with a pinhole in the weld area.

 

It never crossed my mind that the damper could be leaking. I didnt realize they had fluid in them. I'll look at that closer and see what I find.

That would sure be easier to replace than a waterpump!

 

my early 03 willleak when it' s -20 but not when it warms up.guess what i do. i can't find the leak,it must have something to do with contraction due to the cold so i just ad some coolant and don't worry about it.

 

check the t-stat, the upper hose were it meets the radiator they like to leak there and drip down. can be hard to find.

 

upon further review, it appears that the lower radiator *may* be rubbing barely enough to cause a super slight leak. Thats my best guess anyway.

I'm gonna change it out and cross my fingers.

 

Pulled the lower hose today. If it rubbing on the steering box is the cause of the leak, I'll be shocked. The spot on the hose doesnt seem to go all the way through, but I'm replacing it anyway.

I'm starting to wonder if I spilled something under the hood, and forgot about it.

 

I finished replacing the lower radiator hose and found this drip falling from (I think) the tubing for the power steering. It's definitely coolant.

The area around the thermostat seems dry, but it almost HAS to be coming from there so I will check again.

How/where exactly do the thermostat housings tend to leak from?

 

they leak from either the base of the hose or from the o-ring that seals them to the front cover.

 

And the fan can blow it all over. It's in a prime spot for the fan to disperse it. Been there unfortunately. Luckily I had just replaced the t-stat and knew where to look. If you've disconnected the hose get rid of the spring clamp and use a worm gear clamp. That solved my problem.

 

Looks like where mine was leaking.had to pull the fan shroud to find it,ended being the upper radiator hose where it connects to the radiator.once you pull the shroud you can see everything,and will likely find your leak.looking at the pic of the fan it looks like its been blowing something on the rear shroud.the other thing you could do would be to pressurize the cooling system and check.