Hey, I have been loosing coolant for about a month, first noticed it when my temp gauge started rising and immediatly pulled over and got a friend to take me to get some pre mixed coolant. Ever since then, I have been leaking about half of the coolant in the overflow a week. I had the radiator system tested for leaks and Tire Kingdom said they couldnt find any, I am not blowing any smoke so I dont see how it could be a headgasket and my mpg has not been affected... anyone have any ideas of what to look for or where to look?

I was in a front end collision back in february that pushed my ARB back 1" and up 1" on the drivers side.. dont know if that could do anything but figured i would throw that extra info out there,

thanks for your help and advice

 

water pump will usually leak when its internal seals go.

 

well i guess its time to jack her up and see if you can spot any green drips. look and see if its collecting in the skid (will tell you that its above the skid, or at least that its driping onto something that drips onto the skid.)

 

should be red drips

 

well that all depends on the coolant you use. theres green stuff in all 5 of the vehicles on the driveway. and as far as ive delt with it, seems to be the most common.

anyway, just look for a coolant leak... it wont be oil or tranny fluid nor brake or power steering. im assuming you have no other leaks, so just find something leaking that isnt perfectly clear water, that will be AC condensation.

 

mine is actually kind of a pink, and i dont currently have my front skidplate on (since the wreck in february, havent wanted to take it out offroading so took it off to save on weight/gas) what do you guys think about filling it up turning the truck on and putting a large white sheet or cloth underneath the front end? if the water pump internals are leaking is that something that you repair or do you just buy a new water pump? also, how much would a water pump be and where would you get one, besides the stealership?

thanks for the fast responses guys, keep them coming, tomorrow morning im gonna go check where im leaking

 

oh... and funny story about having no other leaks, my power steering rack is leaking, but i know where its leaking from and i know what it looks like already, so ill just look for an additional leak

 

okay, got under there and found what seems to be residue from a leak, think this could be where im losing a half of an overflow tank in 2 days through??

bottom of the radiator looking towards the front bumper (notice the hole where my broken @$$ winch should be)


taken looking towards the passenger side

 

bump.... bump, got all day to work on the truck, gonna start cleaning her up so if anyone that sees this thread knows if that is where im leaking from or can take an educated geuss it would be much appreciated

 

try blocking off the heater core for awhile. simply get a right size tube, 5/8" or 3/4" (i dont know which, but cost about $1/ft) and block off the inlet and outlet. this will eliminate the possible of leaking heater system.

after that, id check backward from hose to hose.....

if youre wondering about water pump leaking, id doubt it. the leak at the pump is usually unbearable, engine can easily be overheated.

 

get it really really dark and pull out a black light (the fluorecent kind) and the coolent will glow (it's really cool)

 

okay, profuse, im kinda having a hard time understanding what you mean right now... care to elaborate? my mind is not working all the way this weekend... (UF homecoming and we beat LSU!!!) so then i shouldnt worry about the water pump?

oly, now you have forced me to drive my broke truck to walmart just to see if it really works, gotta wait till night time to try it though

 

simply speaking, bypass the heater core. take off the two tubes that goes in and out of the heater core, then use a single tube to connect the inlet and outlet. this mean that youll temporarily lose the heating system until you reconnect the tubes.

id do this because its simple and easily eliminate a system that may cause the probelm.

btw, my neighbor had this similar problem on his chevy blazer and it is like you described. turns out to be his heater core.

 

My 98 would leave me small puddles of coolant occasionally & I couldn't pinpoint it. While replacing my thermostat, I found the original O ring seal was shot. Installed a new thermostat with a new O ring & no more leaks.
Hope it's that simple for you too...

 

in your last picture, the fan shroud appears to have red coolant on the far right hand side, i can't tell for sure.

please post pictures of these places.

front crank pulley from the bottom of the vehicle

oil cooler on the left side of the block

The most comon leaks I see and order of occurance

1 water pump
2 oil cooler bypass hose (goes from the water pump to the oil cooler)
3 upper radiator hose (i hope you would see this though, this part# was changed by toyota for this problem)

I have never seen or heard of a heater core leaking on a 02 4 runner, not likely. Though, do you smell a sweet smell in your runner? when hot? Smell you heater vents

Look for white/red krusties, toyota coolant is the best for finding leaks and usally gives it's self up quickly.

 

i had this issue ffor a long time for some odd reason i boil water out of the radiator into the overflow. then overflows the overflow. then sucks most of it back up. I even put a new toyota cap on and it still did it but the temp on the gauge never got any higher then midway. havent really checked lately to see if its still happening with the 3.4 but it doesnt seem to be.

 

hey mudbutt, ill take as many pictures as i can that will be helpful, i appreciate everyones input in helping me figure this leak out!

 

There are so many places that coolant can leak that it would be rediculous to mention them all here but typically when looking for a leak I pressure wash off the engine as best I can. Then I refill the radiator and overflow, adding dye to the coolant (most coolants do glow under blacklight already, but adding dye makes sure this is the case....try the blacklight on some coolant first to see if it glows before adding the dye) if needed. Coolant safe dye is available at most auto parts stores if you need some. Blacklights can be found in the same size as a normal bulb, they are very cheap, even Walmart usually carries them. Now wash off any spilled coolant from refilling. Now run the motor up to temperature and while running use the blacklight to find the offending area. That is a pretty decent leak so it should be blatantly obvious within about 20-30 min of driving. If you don't find any external leaks at all (not very likely), then you need to think about other possibilities (ie HG, etc).

Blacklight example:
http://www.physlink.com/estore/cart/BlackLightBulb.cfm

 

thanks MTL... im going to go to wally world later tonight and pick up a black light... my engine needs a good cleaning anyways, so atleast now i can have a reason to do it besides vanity... thanks everyone!

 

don't steam clean it till you look for the white/red krusties