Coolant Leak Diagnosis (1 Viewer)

[rjlc]

Hi everyone! Trying to troubleshoot a coolant leak. I've gone through other posts - looks like the plastic T's can be a culprit for 100 series. I'm seeing something a bit different from the front of the engine but it doesn't look like it's the water pump.

When I first got this, it had a leak - I was able to fix it by replacing the old coolant hoses. Last weekend I took it through some dunes and pushed it pretty hard. Now it seems to be leaking again and over the course of about 400 miles I lost 40% of the overflow reservoir. Looking from underneath, here are some pics of what I'm seeing.

 

[OEMGUY0720]

Have you check anywhere higher than the water pump? If it’s dry up there (thermostat area), leak is likely to be coming from the water pump.

 

[rjlc]

Have you check anywhere higher than the water pump? If it’s dry up there (thermostat area), leak is likely to be coming from the water pump.

I'm not seeing anything up top but am trying to reproduce the problem to see a visible "active" leak.

In the past (previous owner) it did have a coolant leak from the thermostat - around that time they replaced everything (thermo, water pump, and timing belt) but the stains are still there.

 

[Mike NXP]

Top off fluid, clean it, and monitor it like any other leak. That being said, In that area you have cooling lines that run up near the oil filter. Start there.

 

[Mike NXP]

Sorry, I got turned upside down. On the alternator side that may be transmission fluid cooling lines. Fluid looks blood red, maybe transmission fluid? Sorry if I'm no help

 

[rjlc]

Top off fluid, clean it, and monitor it like any other leak. That being said, In that area you have cooling lines that run up near the oil filter. Start there.

View attachment 2852426

View attachment 2852427

Great point will do that! The old coolant stains are confusing things a bit - will clean it up and top off and go from there.

 

[rjlc]

Sorry, I got turned upside down. On the alternator side that may be transmission fluid cooling lines. Fluid looks blood red, maybe transmission fluid? Sorry if I'm no help

Thank you Mike! I was able to capture what dripped on to the engine shielding - the coolant and trans fluid are both red, but this coolant (thankfully i guess )

 

[JunkCrzr89]

Thermostat housing, front bypass gaskets, or water pump..

 

[highonpottery]

For about $30 you can get a UV leak detection kit and see where it's coming out

 

[rjlc]

any downsides to performing a pressure test?

 

[Smiles]

For about $30 you can get a UV leak detection kit and see where it's coming out

Agreed, always start with the easiest & cheapest things first.

 

[Mike NXP]

Agreed, always start with the easiest & cheapest things first.

The easiest and cheapest thing would be to clean it up and visually find the leak. Unlike diagnosing an AC leak, a UV dye is not necessary for finding most coolant leaks.

@rjlc Why are you thinking about a pressure test, is it tough to see where the leak is coming from?

 

[Smiles]

The easiest and cheapest thing would be to clean it up and visually find the leak. Unlike diagnosing an AC leak, a UV dye is not necessary for finding most coolant leaks.

@rjlc Why are you thinking about a pressure test, is it tough to see where the leak is coming from?

Disagree

 

[Mike NXP]

Disagree

What are you disagreeing with? That it's cheaper to clean and observe the leak than spend money for a UV test which adds crap to your system and cost money and is just all around not necessary.

These engines are pretty easy to diagnose coolant leaks on. Clean the area , top off fluid, and inspect for leaks. If that fails then sure you can take it to the next level of diagnosing.

 

[rjlc]

The easiest and cheapest thing would be to clean it up and visually find the leak. Unlike diagnosing an AC leak, a UV dye is not necessary for finding most coolant leaks.

@rjlc Why are you thinking about a pressure test, is it tough to see where the leak is coming from?

It looks like I have a few very small leaks - over about 500 miles I lost 40% of the overflow reservoir. I found 1 leak which is either the radiator itself or where lower radiator hose connects to the radiator. The other leak seems to be front engine towards the bottom somewhere...but it's very small and hard to tease out. That's why I was thinking about doing a pressure test so I could pressurize and watch to see an active leak.

 

[94SRUNNER]

It looks like I have a few very small leaks - over about 500 miles I lost 40% of the overflow reservoir. I found 1 leak which is either the radiator itself or where lower radiator hose connects to the radiator. The other leak seems to be front engine towards the bottom somewhere...but it's very small and hard to tease out. That's why I was thinking about doing a pressure test so I could pressurize and watch to see an active leak.

View attachment 2853046

Based on this picture, it appears (based on the dried pink coolant on the lower coolant hose) that coolant is leaking from higher up. I would check the top of the lower coolant hose where it connects to the thermostat housing. Not to say it isn't leaking at the bottom connection of the lower coolant hose.

If it were me, I would try an clean everything off with water, let it dry, then go for a drive until you are up to operating temps. Then pop the hood and start investigating for your leak locations.

 

[rjlc]

Going to bite the bullet and just change out the water pump, timing belt, etc... Probably something I should have done from day 1. The leak, wherever it is, is very small. My feeling is, the water pump and timing belt which were replaced not to long before I bought the truck are likely all AutoZone garbage. The belt is definitely, and other things I've replaced in the past have all been bad aftermarket stuff. My guess is that the water pump is functional but the gasket is likely no good and failing under pressure. My hoses are new OEM, but there seems like there is a leak right at the connection of the lower radiator hose.

 

[jerryb]

don't use worm gear clamps.
if it's not obvious, the pressure test allows you to not have to run the car to get pressure and there are no wind affects blowing coolant around.
I've always found leaks that are hard to see with it. There is zero downside, and it's free to rent.
Doesn't get more basic than that.

 

[rjlc]

don't use worm gear clamps.
if it's not obvious, the pressure test allows you to not have to run the car to get pressure and there are no wind affects blowing coolant around.
I've always found leaks that are hard to see with it. There is zero downside, and it's free to rent.
Doesn't get more basic than that.

You're absolutely right - one of the leaks is from the worm clamp itself eating in to my hose...

 

[Mike NXP]

You're absolutely right - one of the leaks is from the worm clamp itself eating in to my hose...

Agreed, I used the same worm style clamp on my lower hose which was leaking shortly after, very slowly. Swapped with OEM when I did the timing belt and shes been leak free ever since. Hopefully you're on the right track for a fix.