Mystery Coolant Leak

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Bloomer

Bloomer

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Been reluctant to post this up, but as HIH approaches I am getting nervous that I've not located or duplicated this minor leak.

My land cruiser is not a DD, and shamefully admit it spends more time in the garage than it does on the road (or better yet, trails).

While installing the front bumper a few weeks ago, I noticed a small (3"x3") pool of coolant on the garage floor. Having a better view of the radiator with the front end disassembled, I noticed what appeared to be a dried trail of coolant from the PS of the radiator. Note, it also seemed the trail of dried coolant continued down the skid plate to the place where it dripped onto the floor. Wasn't too worked up about it as I have warranty left on the land cruiser and would just have the radiator replaced when it was back at the dealer for the realignment after install of the bumper was completed.

Dealer kept land cruiser overnight and ran a pressure test on the radiator (at normal operating temp) with no leaks found. I've checked hoses and hose clamps and cannot locate the source. Since then, I've driven about 500 miles and still cannot duplicate the leak. I've had water pumps leak prior to complete failure, but normally (for me) this has occurred relatively quickly after the initial indication of failure. For what it's worth, the land cruiser has 50,000 miles.

I'll probably get another 500 miles on the land cruiser before HIH. If there's a problem lurking, I'd sure like to address it before hitting the road to Co. Of course, the dealer will not do anything until they can replicate the leak.

Any ideas on what to do or where to focus my attention to ensure I don't have a failure on the road?

Thanks.
 
If the radiator pressure tested out ok, I would think water pump bearings, hose clamps, or radiator cap. I'm not sure where they hook up a pressure tester but it would stand to reason they use the cap opening. I had a small leak on my Tacoma's radiator cap that was easy to fix with a new cap. You might check the seal on your cap and see if it looks old and cracked. Other than that, good luck.


...via IH8MUD app
 
I've had some of the clamps that needed re-adjusting. Also, some spillover from the reservoir when I ran the truck pretty hard in high temps.
 
It might be worth paying for an independent cooling system pressure test from another shop. Did the dealer do a dye test? It's hard to believe you had a puddle on the garage floor from a leak that wasn't picked up in a pressure test.
 
Agree new cap and check the reservoir. With only 50k on your 100, sounds way to early for water pump problem, but maybe putting under pressure over night forced some out the weep hole and after you got it home it leaked down onto the floor. You don't mention seeing anymore leaking after this one time?
 
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Assuming the pressure tester was set up in the neck of the radiator [SOP] the radiator cap is still a suspect. If the system help pressure overnight then replace the cap on spec.
The water pump is the second suspect. As the bearings wear, coolant will leak from the aptly named weep hole in the pump, run down the timing case, and appear below the crank pulley at the joint between the timing cover and the engine block. Check there for signs of red crusty residue from dried coolant.
 
No noticeable signs of leakage since the pressure test, but again I've only driven around 500 miles. Also, the coolant on the floor of my garage was discovered before the pressure test. I had the pressure test done as a result of seeing the coolant. Sorry if I wasn't clear on this.
 
Bloomer, from what I've read, heater Ts are a mileage wear item, rather than age worn. Have you swapped your rad cap?

With the big trip planned, I'd hate for you to get stranded. Hope you find the culprit.
 
Not yet, it's on my list of things to do. There's no coolant residue around the cap or overfill line. From what I understand, the SLLC will leave a pink crusty residue where leaks occur, which is what I saw on the radiator where I originally suspected the leak ( over night pressure test evidently proved me wrong). Hopefully, it's the cap and I won't have any problems on the trip. With only 50,000 miles, I'm thinking water pump, heater T, and even radiator failure is a bit premature.
 
Could totally be the heater T - mine went out at 115k but I can remember quite a few posts regarding age degeneration with the hose T - not just mileage. If you haven't done them yet it's easy and cheap to at least throw one in the trail kit. I would bet the heater T has something to do with it. I didn't read you post well enough at first (and figured the heater T would have been ur first look cuz of how well it is documented here), and thought u described the puddle as under the radiator but then just read it was actually under the engine. My understanding about hose ts was that the hotter the climate where u live, the less time/mileage it would take to fail.


...via IH8MUD app
 
Dealer kept land cruiser overnight and ran a pressure test on the radiator (at normal operating temp) with no leaks found.
Click to expand...

This is simple. A pressure test uses a simple air pump and gauge. Think bike pump that is adapted into the coolant reservoir neck.
- If the pressure holds overnight, you have no coolant leak in the system. If its still loosing coolant then the reservoir cap is suspect.
If the dealer ran a system pressure test and it held pressure overnight its unlikely that you have a leak. The fact that they said they ran a test may not be proof that they actually did it right.
- If the pressure drops, its because there is a leak. All you have to do is find it.
The pressure test lets you run the cooling system at operating pressure without the engine running. Its much easier to locate the leak that way.
 
pwcummings said:
Could totally be the heater T - mine went out at 115k but I can remember quite a few posts regarding age degeneration with the hose T - not just mileage. If you haven't done them yet it's easy and cheap to at least throw one in the trail kit. I would bet the heater T has something to do with it. I didn't read you post well enough at first (and figured the heater T would have been ur first look cuz of how well it is documented here), and thought u described the puddle as under the radiator but then just read it was actually under the engine. My understanding about hose ts was that the hotter the climate where u live, the less time/mileage it would take to fail.


...via IH8MUD app
Click to expand...

Haven't seen any low mileage heater T fittings going bad. Can you post some up? Thanks PWC.
 
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