Home for the holidays in my beloved 4Runner dripping coolant onto my parents driveway. Rate of drip is enough for 1-1.5 liters overnight while not running.

It appears to be coming out from the cylinder on the drivers side engine. What is the purpose of this piece and how hard to fix gasket. Access is limited from below and through wheel well.

Thanks

you mean the head gasket?
Can you pose a picture of where exactly it is leaking?

Did you over heat your truck with in last 10 months?

Oil cooler perhaps? Do these engines even have an oil cooler?

Sorry,

I'll fix that picture. I posted that on an incredibly crappy tablet (they are all crap).

Now that I'm at a computer I can do a better job.

The leak is from the cylindrical "manifold" under the exhaust header and ahead and above of the clutch slave cylinder in front of the bell housing. it has two coolant lines going into it. I imagine it's some sort of bypass. Connections to the cylinder are dry. It's the gasket/oring from this cylinder peice onto the block.

It has not been over heated, if anything it's been too cold. I bought this truck this year and have never tested the coolant. I drove it 6 hours the day the leak was discovered in -25 (wind chill of around -30 celcius). The coolant dripping out was not frozen so my hopes are pretty high that the coolant is the right proportions for these temperatures.

EDIT: You can now see the cylidner on the picture I borrowed from TTROA. Its to the right of the oil filter and engine mount. It appears the coolant line coming from the right side of the water pump (from front of vehicle) goes around the oil filter, around the mount, and into this cylinder.

Sadly, my service manual and information on my truck is at home. I'm tempted to limp it back the 6 hours stopping every hour or so to check coolant level. This way I have my own tools and better availability of parts. Sadly, it's my only vehicle so I do need it fixed for work or I'll be renting a car till I can repair it.

I'm going to look pretty stupid saying this.... but is that the thermostat?

Most (all?) t-stats I've seen are inline and just open and close depending on temperature. Is this Toyota's version of a t-stat for the cooling system?

I take it that the engine on the stand is not yours then? I love where the oil filter was relocated to.

I'd do a compression test first and go from there to see if it is a cracked head gasket. If all the numbers read good, then look at the oil cooler lines for cracks as well as the o-ring gaskets for the oil cooler (the thing to the right of the U shaped hose in the pic).

yup!

You got it right. Oil cooler. I just found it on a service manual I found online.

Thanks so much for those who do this for all of us. I have a copy at home, but not here. Thankfully the guys at TTORA had some online.

Here's a picture:



Now would the o-ring be at fault, or the cooler itself is the question?

The motor shown is not mine. It was just a clear picture I found while looking for somebody with the same issue as me. Many people apparently have the coolant lines above the engine crack and leak into the manifold space. This is not leaking from there, and it's pretty clear it's not leaking from the head gasket either. I guess an internal leak could pressure the system causing it to leak when engine running, but it leaks when not running as well.

I'm going to go rent a cooling pressure test tool today if possible and do the tests. Seems easy enough especially if I don't have to buy the tool! Then I can narrow down what parts it might be.

Thanks for the helps guys! I'm hoping it's as simple as replacing that 0-ring. I wish it was warmer than -25 though! Brr

Check the coolant lines going in and out of the cooler. I suppose the O-ring is to keep oil in. These lines are known to crack.

Coolant lines appear good and free from cracks. I was hoping that was the case. It would make the fix easy.

It does appear the o-ring and bolt seals are to stop oil, not coolant.

I'm starting to think my cooler is faulty...

Scroll under the truck and check where the leak is. It is easy to fix things when you find the location.

Check the freeze plug/s. mine started to leak and its getting replaced as we speak. it was the one right above the oil filter.

Yeah, you have to locate the place before removing it.

Its stopped leaking only because I think it ran out of coolant. I have picked up some more.

I've been under the vehicle multiple times. Visibility in this location is not good. There is a chance it might be the block heater plug but well see. I might fill coolant and try another 10 minutes to see where it's leaking before I'm too cold.

Shibby!,

I was multitasking the last post. It would not be the oil cooler O-rings; if they fail you see oil, not coolant. But double check those hoses.

If a freeze plug begins to leak I have never seen it turn into a gusher. Then again, I have never been in -25 degree weather either. Definitely something to check.

It's not a gusher but did leak out the majority of its engine coolant in 2nights of being parked. I think the tstat prevented the rad from being emptied because it only took about 500-750milimeters (2-3 cups).

Tomorrow I'm going to do a little test before possibly buying a pressure tester. Nobody rents them here and prefer not to buy.

I need to determine if it's the block heater or oil cooler. Then work on the fix. I'm hoping the block heater! (it's located at the rear most freeze plug)