twowheeled

91 4runner with the V6, 110k miles. It was running great yesterday on the highway, although I made quite a few WOT passes and had it all the way up to the limiter. This morning I started the truck and let it warm up while I shoveled my walk. Got in to go and noticed the temp needle on high.. uhoh.

I drove it a few blocks and it dropped back to the middle of the range.. so I drove it for another few blocks. Every time I hit a light and idled it went back to red, so I turned around and limped it home. I also had no heat thru the vents.

Pop the hood and check the coolant, overflow bottle is empty and can't see any under the rad cap. The rad takes about 2 quarts to top up. I filled the overflow and started it back up, still no heat.

The oil isn't milky, but exhaust def smells sweet. I think I might have a cracked hose or rad that let the coolant leak out overnight, but wondering if that is even worth fixing now I noticed the exhaust smells. I've been saving for a new truck so if the headgasket is done, I'm not rebuilding it. Any advice?

six6vetteguy

Do a pressure test with the engine off on the cooling system. You can rent them for free from Oreilly's or Autozone if you don't already have one. You will be able to see if it holds pressure and will also be able to hear the leak so you will know where it is coming from. You can also do a compression test on all cylinders....If two consecutive cylinders are low, the gasket is blown between them.

hang10

Why were you making WOT "passes" and red-lining a 3.0 toyota 4runner in the first place ??

rustyf99

iTrader: (1)

If you overheated it when low on coolant, you blew a HG. If you're willing to give it up for free, wheel it over to my place and I'll put in the garage next to the one I'm fixing this weekend!!

Otherwise, the parts are about $250 bucks (assuming you don't need "the works") and just a whole lotta time and patience to disassemble and reassemble...lots of help on here though!!

twowheeled

we're not talking about top speed WOT passes, I had it wide open while MAKING passes on big trucks on the highway. It's all two lane so you need to have the pedal to the floor, ECT on, and click the OD off if you want to pass anything.

I just bought a cap pressure tester (no free rentals here in canada we're a facist nation) and the system holds about 2psi before it starts leaking. Leak is coming from the front of the block it doesn't look like a hose.. might be the water pump? I've got it in the garage with the heaters on full blast before I venture out there to pull the skidplate and have a closer look.

It wasn't overheating on the highway at all, once I filled the rad back up and the overflow, the needle stayed smack dab in the middle of the range again and I got heat thru the heater core. I think it might have cracked awhile ago because we had a dip down to -40 last week. I probably never noticed because on the highway at -20 the system just wasn't getting very hot? So not much pressure/coolant loss until I parked it.

twowheeled

Ok.. just pressurized the cap it looks like the leak is coming right from the water pump. Not sure if it is just a seal or just the pump itself or the T-stat. How big of a job is this? I'm guessing at least I will need the front grill off, drain the cooling system, take off the belts, and pull the pump off. I need this truck to get to work on sunday so if it's going to take a couple days I'll bring it to a shop..


edit- crap, I just did a search and saw the pump is timing belt driven?? I'm guessing if it's a pump seal I can't just get the pulley/pump off real sneaky like and fix the seal? I don't want to do the timing belt, don't have time and don't want to pay a shop to do it.

Team420

Its not that bad, just plan on an afternoon, a 6pack (get 12 just in case), and a few wrenches. 1 quick tip.... start the motor before you put it all back together... nothing worse than finally getting it all back together, to find a cam jumped a tooth, and its all coming apart again to get it right..... lol dont ask how i know

* its also easier if you have a bench vice, it makes compressing the tensioner a heck of a lot easier (assuming you have a hydrolic tensioner)

six6vetteguy

It isn't that easy for a beginner. Gotta make sure you line all the pulleys up with the belt and timing cover backing. If you are reusing the belt, make sure it is dry before you put it back on. I would guess about a 4 hour job if you don't run into problems and have all the parts. Also, things to consider: Need a harmonic balancer remover to get the balancer off. An impact gun helps with the balancer bolt too. set the engine to TDC #1 compression stroke before you start. After the belt is back on, turn the motor over twice by hand to make sure nothing hits and that the timing marks all line up. Don't start it like the guy before me suggested. Cause if it is off a few teeth and the valves hit the pistons, you are floating in gummy bears.

twowheeled

can I get away with just taking the tensioner off, pulling the pulley off the pump and then slipping it back on without touching the cam cover and timing? I thought this was a noninterference engine why would the valves hit the pistons?

justin_4runner

i would and had to pull all covers and reset the timing on mine before, but its best that u do pull all covers to make sure u get it all put back in the right spots.

six6vetteguy

It's the 3vze engine, right? I don't think those are non-interference. You will probably have to take the belt all the way off to install the waterpump...even with the tensioner off, you still don't have that much room.

Stumped

ok....I was skim reading this last night, plus already having a few beers, I have decided to change my post. If your weep hole had been leaking for a while and the rad was low, then it would cause the symptoms you mentioned. I do however see this is an older post, so you must have already fixed the problem?

ZUK

iTrader: (1)

I'm thinking that your radiator water was frozen...the morning you were shoveling. Hope you're not running mostly water with little to no anti-freeze......

FattMaanLittleTruck

blown hg