(FIXED) Coolant Leak

Get a 5th gen they said, the 4.0L will be bulletproof they said



I can't physically see any leakage in the area while the engine is running. Best guess based on the splatter pattern and concentration of dried fluid, is an intermittently blown O-ring connecting the coolant bypass pipe to the thermostat manifold. I'll pick up a pressure tester and try to verify. Hopefully the coolant bypass pipe itself hasn't rusted through, which would be a big job to replace on the 1GR.



In the meantime, I'll refrain from "Italian tune-ups" and carry extra coolant. The Toyota SLLC jug fits suspiciously well in the rear cubby:

 

Ouch!

 

how many miles? Have you pressure tested?

 

^151k miles. Got a pressure tester ordered from Amazon.

 

Clean the area well so there are no coolant remnants. Drive a while so it's been at full temp, watch area for leaks, use UV light if needed.

 

yeap, same here, got the 4 Runner based on the alleged bulletproof engine. Had a coolant leak around 33K miles they had to replace a lot of things as they also found some kind of oil leak once they dug into fixing the coolant leak. Thankfully fixed under warranty but still, sucks, not what I was expecting.

 

What?

 

Surprised to see this and to hear someone else had a leak with low miles. At least you made it to 151k (not sure how many years).

I have a JGC that started bleeding to death in the garage because the coolant lines went soft and started leaking - all of the hoses had to be replaced. It was only about 4 years old with about 70k miles. I was super pissed because the previous model went over 13 years and 215k without needing the hoses replaced

 

Bummer, man. Hopefully it's just a pinhole in a hose or a weak clamp. Test the cap, or just replace it while your at it.

 

A guy I work with has a late model JGC with the turbo diesel engine. He bought an extended warranty, and has used it extensively. It's currently in the shop again, this time for overheating and going into limp mode.

 

Crappy Italian motor

 

I've had the dealer strongly encourage me to get an extended warranty on it ever since I bought it used many years ago. It wasn't a money ploy either - you could see the genuine concern on the service departments faces. I had hopes that the hemi v8 was tried and true and I wouldn't need it but the past couple of years it's cost 6k+ to keep maintained due to broken parts and electrical sensors. Not all of those were engine related but it was pricey to replace all 16 spark plugs (apparently there are two per cylinder) and replace the motor mounts. If the air suspension goes, that's at least 7k to fix.

We've only kept it because it's paid off and repairs are cheaper than a new car payment but we're probably one more major repair (3k+) away from finding a replacement. I keep trying to pick something for my wife (I pawned the JGC on her so I could buy the 4runner) and had hopes for the new LC but we passed one the other day and she said it was ugly. She also told me to stop trying to pick out her next vehicle

 

Woah that thing spewed! Also hoping it’s just a pinhole in a hose, or at least something that’s easily accessible.

 

Turned out the coolant leak was my own doing. The Toyota adapter for the pressure tester arrived today and I was able to put some pressure in the system. At 14 psi a steady leak formed at the upper radiator hose going into the thermostat manifold:



The fix was to reposition the clamp a little and cinch it down with a small ratchet. I then pumped to 15 psi, no leaks and no pressure drop after 15 minutes.

Made a cutout in the upper radiator shroud, so the radiator cap can be accessed in the future without removing the shroud:



Tools used:
8MileLake D0065631 radiator pressure tester:

$50 8MILELAKE 14pc Radiator Pump Pressure Leak Tester Kit Vacuum Pressure Cooling System Tester

https://www.amazon.com/8MILELAKE-Radiator-Pressure-Tester-Cooling/dp/B07GQN18YF/
Motorad 3125 Toyota radiator adapter: https://www.rockauto.com/en/moreinfo.php?pk=5551020&cc=0&pt=2054&jsn=1

 

Glad you got it figured out and even happier that the reputation of 5th gen reliability and durability has been restored. Long live the king!

 

How was it your doing?

 

he used wrong clamp. Toyota clamp "alive" and maintain grip at temperature fluctuations. clamp OP used was installed and tightened cold. when engine warm up, hose squished under that clamp and eventually gets "cut". Instead replacing hose and clamp with OEM parts, OP just pulled hose little more and used wrong clamp. I am sorry for bad wording, not very technical. Resume: always use OEM parts.

 

https://www.4runners.com/posts/607852/
I placed the hose clamp too close to the lip of the manifold outlet. It may have been exasperated by the Gates hose's bend radius near the end being slightly off. I normally prefer Continental hoses (like the lower hose I used), but the Continental upper hose wasn't in stock at the time of order.

 

The OEM spring clamps don't survive our salty winters because they aren't stainless steel. In the rear of the 4Runner, I've already had to replace a few spring clamps in the evap system that had split open from rust. It's also a constant battle with my father's Subaru - every few months, a factory spring clamp fails and causes a transmission fluid leak; I replace it with an SS hose clamp, the leak stops, then another factory spring clamp fails soon after. Fortunately the Subaru's transmission still has a dipstick, so it's easier to top up.

Automakers use spring clamps in the factory because they're faster to install and can't be overtightened (less prone to assembly error when a worker installs 900 of them each shift). The constant-tension business doesn't come into effect at typical passenger car hose sizes.

 

Good deal, Easy fix!

Did your previous hoses get soft , or did you replace them as preventative maintanance?

 

^Preventative maintenance. Nice round number for replacing belts, thermostat, radiator hoses, etc. is 10 years. This 4Runner is 14 years old.

 

14 years is a really good run. They must be making better hoses, since I can’t remember the last time I’ve ever felt soft/bulging OE hoses.

 

I used those clamp on our Corolla, ended up ordering OEM clamps and replacing. They could not keep enough pressure on the hose.

 

I haven't replaced any, but yes, all the clamps under hood look like absolute garbage on my 178k 2013 New England 4R.

I guess one good thing is that should I decide to sell it, the rusty clamps show that nothing has ever been messed with.

 

^Should check the clamps in the area of the evap canister above the spare tire. A few are probably gone.