Coolant leak - looking for preliminary ideas

mooch91

Member
All,

Just noticed the past two days two drops on the ground looking like they're coming from either corner of the front crossmember/radiator.

Popped the hood today to see coolant at spots along the bottom of the engine area (skid plate, crossmember, radiator, etc).

Only thing I've done recently was to top off the coolant reservoir (just bought the truck and it was at the lower end) and pop the radiator cap to ensure level in the radiator was at the top. I had been keeping an eye on the level in the overflow and it's been between the two marks. I used a funnel and was clean with topping off the reservoir.

I realize I'm going to have to get eyes on the truck a bit more and spend some time searching for the issue this weekend, but I wanted to see if there were common spots to look. Truck has 167K.

I'm thinking radiator, reservoir leak (unlikely), cap (unlikely since I don't know why this would be causing dripping down below), or hose.

It was just interesting that all's been fine until I topped off the reservoir.

Thanks.
 
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I'd look at any area with pink crust. Hopefully its that easy.

Other than that, you'll have to look around like you said.
 
I'd look at any area with pink crust. Hopefully its that easy.

Other than that, you'll have to look around like you said.

It's only been a day or two, so nothing seemed crusty at a quick glance. Will check around tonight or this weekend and report back. Thanks for the thoughts.
 
In my experience, when the factory radiator fails, it tends to fail in one of the lower corners. Radiator replacement in the 4th generation 4runner is a fairly quick and easy job. Denso make a quality, factory spec, drop in replacement for short money....check out RockAuto....great parts and prices. You may also want to consider replacing the thermostat and radiator cap while you're at it. Good luck!
 
I just went through this exact same problem on mine. It turns out I had coolant leaks in a couple places...ended up replacing the thermostat, lower radiator hose, radiator and radiator cap. The whole process is super easy...maybe took me 2 hours and that was me taking my time and cleaning stuff up along the way.

Check all your hose connections to make sure they're tight. I found the hose clamp was loose on the lower radiator hose at the thermostat...but I also found a small crack in the plastic housing on the thermostat so those might have been related.

At 167K miles, a new radiator/cap/thermostat wouldn't be a bad preventative maintenance step anyways.
 
All,

Just noticed the past two days two drops on the ground looking like they're coming from either corner of the front crossmember/radiator.

Popped the hood today to see coolant at spots along the bottom of the engine area (skid plate, crossmember, radiator, etc).

Only thing I've done recently was to top off the coolant reservoir (just bought the truck and it was at the lower end) and pop the radiator cap to ensure level in the radiator was at the top. I had been keeping an eye on the level in the overflow and it's been between the two marks. I used a funnel and was clean with topping off the reservoir.

I realize I'm going to have to get eyes on the truck a bit more and spend some time searching for the issue this weekend, but I wanted to see if there were common spots to look. Truck has 167K.

I'm thinking radiator, reservoir leak (unlikely), cap (unlikely since I don't know why this would be causing dripping down below), or hose.

It was just interesting that all's been fine until I topped off the reservoir.

Thanks.
definitely your radiator. it must have been just coincidence. dont wait too long because when it starts leaking, that slow leak can become a waterfall in a few weeks. i agree, replace your thermostat too, radiator cap and the hoses. its about time for that mileage.

Sent from my SM-G930T using Tapatalk
 
definitely your radiator. it must have been just coincidence. dont wait too long because when it starts leaking, that slow leak can become a waterfall in a few weeks. i agree, replace your thermostat too, radiator cap and the hoses. its about time for that mileage.

Sent from my SM-G930T using Tapatalk

Even before looking at it further, I ordered up a radiator, hoses, and a belt for the weekend. Looks like an easy swap. Even if it's not that, I may do it preventively since the parts were not too expensive.

I'm going to use the Zerex Asian coolant.

I'll save up the cap and t-stat for later since they should be easy enough to do without disassembling.

Thanks for all the ideas.
 
I'll save up the cap and t-stat for later since they should be easy enough to do without disassembling.

Just my $0.02, but I'd suggest doing the t-stat with the radiator. You already have the system drained and it's literally 3 bolts...super easy job. If you wait, you'll have to drain the system again which is kind of annoying.

Caps are on sale at RockAuto right now for something like $1.50....
 
Radiator it is!

Mine was leaking from the top on both sides, primarily the driver's side. I've read that most leak from the bottom.

Got it all broken down today, waiting for the parts to arrive tomorrow. Amazon don't let me down!
 

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Job done. Amazon came through.

New radiator, new belt, new hoses, fresh coolant. Drained the block too so it ended up being nearly a full coolant change.

Used existing hose clamps which were a bear to access from up above. I had always heard the Toyota spring clamps were the way to go, so I kept them.

Only other snag was I snapped the lower tab (for the fan shroud) from the new radiator. It isn't rattling, but I will epoxy it back as soon as I get a chance.

Thanks all for the help!
 
Radiator it is!

Mine was leaking from the top on both sides, primarily the driver's side. I've read that most leak from the bottom.

Got it all broken down today, waiting for the parts to arrive tomorrow. Amazon don't let me down!

That is where mine was leaking as well. No issues since I replaced it.
 
When I replace anything related to the cooling system I prefer to swap both radiator hoses and all heater hoses. Cheaper to do it now versus later unplanned breakdown.
 
Job done. Amazon came through.

I've got a 07 V8, striding along at 171,xxx miles. I took it to the shop awhile back and was made aware of a few items that will need to be repaired. One issue they told me about, and I quote

"Engine coolant level is below specification. Bad coolant leak from under the intake. Recommend drain and fill radiator. Repair the leak."

Now I'm a college student and have my own bills, so putting money back in my truck is a slow process. Guy told me to budget $600 for this repair... seeing you all comment on here how easy of a job this is, makes me feel like I can do this myself. I'm inclined with tools, most practice has been when working on a house or wood working, minimal experience in auto repair. So bottom line I'm asking: Is there a writeup to fix this that you found helpful when completing this task? and could you link where you ordered your parts from?

I'll be doing my own research as well, just figured I'd ask while I was here.
 
I've got a 07 V8, striding along at 171,xxx miles. I took it to the shop awhile back and was made aware of a few items that will need to be repaired. One issue they told me about, and I quote

"Engine coolant level is below specification. Bad coolant leak from under the intake. Recommend drain and fill radiator. Repair the leak."

Now I'm a college student and have my own bills, so putting money back in my truck is a slow process. Guy told me to budget $600 for this repair... seeing you all comment on here how easy of a job this is, makes me feel like I can do this myself. I'm inclined with tools, most practice has been when working on a house or wood working, minimal experience in auto repair. So bottom line I'm asking: Is there a writeup to fix this that you found helpful when completing this task? and could you link where you ordered your parts from?

I'll be doing my own research as well, just figured I'd ask while I was here.

Sounds like you need to find the leak first. Since it's "under the intake", it is likely not the radiator like I needed to replace. Might be a coolant hose or fitting to the intake, or perhaps the thermostat housing.

Keep in mind - regardless of what you find - make sure you get the correct parts for the V8 and not the V6.
 
Sounds like you need to find the leak first. Since it's "under the intake", it is likely not the radiator like I needed to replace. Might be a coolant hose or fitting to the intake, or perhaps the thermostat housing.

Keep in mind - regardless of what you find - make sure you get the correct parts for the V8 and not the V6.

I appreciate the quick response! I'll try and get under there to identify where the leak is coming from. The shop I took it to, I trust and don't think they're gonna take me for a ride, I just know it's always cheaper to do it yourself.
 
So bottom line I'm asking: Is there a writeup to fix this that you found helpful when completing this task? and could you link where you ordered your parts from?

I'll be doing my own research as well, just figured I'd ask while I was here.

I would suggest grabbing a flashlight and taking a look around your radiator, thermostat and coolant lines both from above and below the vehicle. Make sure you do this when your Runner is dry (i.e. not after/during a rain storm, snow storm, after a car wash, etc). You're looking for a colored fluid (should be pink) either dripping or crusted. On the radiator itself, you'll want to look behind the fan shroud, which is a little tricky. I if you move towards the back of the engine and look towards the front, you'll have a better chance of seeing the radiator.

There are some great DIY videos on YouTube for the radiator swap. Some are for a 3rd gen, the process is pretty similar. Toyota Maintenance I think had the best write-up.

RockAuto has been my go-to with parts. Just did the swap myself a couple weeks ago and it went smoothly.
 
I've got a 07 V8, striding along at 171,xxx miles. I took it to the shop awhile back and was made aware of a few items that will need to be repaired. One issue they told me about, and I quote

"Engine coolant level is below specification. Bad coolant leak from under the intake. Recommend drain and fill radiator. Repair the leak."

Now I'm a college student and have my own bills, so putting money back in my truck is a slow process. Guy told me to budget $600 for this repair... seeing you all comment on here how easy of a job this is, makes me feel like I can do this myself. I'm inclined with tools, most practice has been when working on a house or wood working, minimal experience in auto repair. So bottom line I'm asking: Is there a writeup to fix this that you found helpful when completing this task? and could you link where you ordered your parts from?

I'll be doing my own research as well, just figured I'd ask while I was here.

I'd check your transmission coolant lines also. Theyre right under the radiator support and are a known culprit. Best way to find out is if it is an extremely slow leak when the vehicle is off and more pronounced when it is running. Put a cardboard box under it overnight to check where the leak is coming from. Youtube has all the videos for a 4th gen radiator replacement.
 
I'd check your transmission coolant lines also. Theyre right under the radiator support and are a known culprit. Best way to find out is if it is an extremely slow leak when the vehicle is off and more pronounced when it is running. Put a cardboard box under it overnight to check where the leak is coming from. Youtube has all the videos for a 4th gen radiator replacement.

I would suggest grabbing a flashlight and taking a look around your radiator, thermostat and coolant lines both from above and below the vehicle. Make sure you do this when your Runner is dry (i.e. not after/during a rain storm, snow storm, after a car wash, etc). You're looking for a colored fluid (should be pink) either dripping or crusted. On the radiator itself, you'll want to look behind the fan shroud, which is a little tricky. I if you move towards the back of the engine and look towards the front, you'll have a better chance of seeing the radiator.
.

I appreciate the help guys! It's been storming here at school the past week or so, so when it drys up I'll give it a look and report back
 
I've got a 07 V8, striding along at 171,xxx miles. I took it to the shop awhile back and was made aware of a few items that will need to be repaired. One issue they told me about, and I quote

"Engine coolant level is below specification. Bad coolant leak from under the intake. Recommend drain and fill radiator. Repair the leak."

Now I'm a college student and have my own bills, so putting money back in my truck is a slow process. Guy told me to budget $600 for this repair... seeing you all comment on here how easy of a job this is, makes me feel like I can do this myself. I'm inclined with tools, most practice has been when working on a house or wood working, minimal experience in auto repair. So bottom line I'm asking: Is there a writeup to fix this that you found helpful when completing this task? and could you link where you ordered your parts from?

I'll be doing my own research as well, just figured I'd ask while I was here.

Just an FYI here, you maybe getting in over your head, while replacing the radiator is a job a novice at mechanics can do IF they are careful and pay attention to how everything comes apart and also has some guidance, i.e. a good step by step video and or a shop manual and understand how to properly tighten the fastners, hoses, know how to make sure you have all the air out of the coolant system, etc.

That being said fixing a coolant leak that is under the intake is another matter entirely, if the intake has to be removed to fix the leak I would highly advise you not to undertake this repair, removing the intake on the V8 or any engine for that matter is not a job for an unsupervised novice no matter what video and or shop manual you have to assist you, you could very well do irrepairable harm to your engine if EVERYTHING is not done correctly!!!

Now on the other hand if you could get someone with the proper mechanical experience (not just a buddy that does weekend work on their car) to assist you/look over your shoulder by all means go for it, but be very sure they know what they are doing and you can trust that they do!!!
 
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Update for anyone that might find this later on:

I've determined the leak is indeed from under the intake. So I will not be replacing the radiator and hoses, etc... I've found my specific leak talked about in another thread here: V8 Engine Leak

I've attached a pic of where my leak seems to be showing
 

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