Thanks for that info MontyMcV.

I'm going to look into the prices right now.

Here is a new question for you folks.

I have noticed that the Montero motor has aluminium heads. These heads crack with the motor overheats.

1. What causes this motor to over heat? Is it simply that the thermostat went bad and the owner didnt pay attention? Is it due to a radiator that is not up to the task? Is it due to the radiator being clogged or in need of repair? Is it that the engine is over worked [climbing a mountain pass or pulling a loaded trailer] and the the cooling system just cant keep up?

2. What can be done with a head once its cracked? Can the crack be welded? If the head is cracked is it also warped? If you can not repair a cracked head where would you suggest I go to find a new one?

3. Is there any way for a person to determin if a head is cracked if it is still on the motor? Say if you were at the wrecking yard. Is there a way to discover a crack on a head that is off the motor? My guess is that there is no way to see the crack unless its magnafluxed.

4. If you have a Montero with good heads how do you keep them that way? What kind of things should an owner do to insure that his motor is running right and not going to overheat?

I sure do apreciate the info this forum has provided so far. I'm very impressed with the quality of info and the assistance and help everyone has shown.

They overheat mostly due to lack of radiator maintenance. The radiator needs to be removed and rodded out to restore flow and cooling capacity.

The most usual story goes like this. No radiator maintenance. Over time, the motor runs hotter and hotter. The heads get some minor warp. Then for some reason, like a busted hose or an unusual load, you get a real bad overheat. Then the heads warp a lot, stretching the head bolts, and killing the head gasket seal. You now have a blown head gasket. The owner tried a lot of stuff, like flushing the cooling system (mostly useless) and some block sealer (way too late and useless) and a new thermostat, then gets a pro opinion of a "bad motor" and looks at the price of a pro repair, and puts in on CL with a note of "needs engine repair".

All aluminum heads crack, because the alloy hardens over time, and there's a lot of thermal stress between the spark plug hole and the valve seats, and not a lot of metal there. Most often, the crack is quite visible to the naked eye or a dye crack test at worst. You can't magnaflux an aluminum head. Magnafluxing requires a ferrous metal. You use the dye test instead. You paint the metal with the usually red dye, wipe it down, then paint a developer over the suspect location, and the dye retained in the crack will bleed thru.

You can repair a cracked head, but by the time you do so, it's more expensive than a good set of rebuilt or new casting heads, since they have to remove the valve seats. I've had one done, once, and it worked fine, but that was before I found Clearwater Heads. They heated the head up overnight to 500*F, ran it down to the welder real fast, and he ground out the crack and tigged it back up. Then they had to reinstall the valve seats and surface the head flat and do a full valve job.

Unfortunately, many folks just fix the heads and not the cooling system, so the head repair doesn't work long. WHile the heads are out, take the rad to a good radiator shop and have them install a new 3 row core on your old (really good quality) tanks. I paid about $250 to have this done, including a new tranny oil cooler in the bottom tank.

Heads are $200-300 each if you need new ones, and the other parts you ought to change are timing belt, tensioners, water pump, front main seal (use oem), thermostat, and water hoses, plus plugs and wires (NGK for both). You need a head gasket set, too, and factory or Felpro are good. You also need new fluids (oil and coolant), some good gasket sealer for the intake joints (coppercoat or indian head are good). You'll spend around $300 or so on the add on stuff.

It takes me a couple of days, working old and slow to tear it down and put it back together. A lot of time is spent on really cleaning up the block head surface with gasket remover and a razor scraper and acetone. Clean all gasket surfaces with acetone to remove all traces of oil.

The main trick to kepping the heads sound is good cooling. It costs less than a $100 to have the radiator taken apart and rodded out, and I'd do it on a 4-5yr. schedule. Good coolant maintenance will extend that time interval. Even with the stock 2 row core on the v6 motors, you have plenty of cooling for most any loading, unless you are towing at walking speed up very steep slopes with minimal air flow.

One last note. The fan clutches wear out, and you get minimal fan air flow at low speeds. I'd replace the fan clutch too. Check the fan clutch by running the motor at about 2500rpms, and kill it while watching the fan. Crank pulley and fan should stop at the same time. If the fan runs longer, the clutch is shot. Costs under $100 for a good one.

Re your vehicle search, I'd think you best buy is to find one that the heads are bad on. You get a real steep discount off KBB this way. I've seen them for $500. Then you spend the $1500 (or less) on doing the heads yourself (not hard, not too tricky with what we know here) and have a very sound motor you can trust. No real special tools needed except a 10mm hex socket for the head bolts (like a big allen wrench) and a good torque wrench and a 22mm deep socket for the crank bolt. TIming belt crank sprockets are sometimes stuck on there, but you just drill them and split them off and get a new one.

If you go this route, I'll write up the whole tear down/ rebuild sequence for you, or download the fsm from MontyMcV's site.

Man, that is great info. I really do aprecitate what you just shared with us Fasteddy!!!<img src="/forums/images/graemlins/cheers.gif" alt="" />

I have one more question. I see a Montero for sale in my area for $500. I've looked at it and have yet to hear it run {bat. was dead}. The owner said that it has an ocational lower end knock sound <img src="/forums/images/graemlins/frown.gif" alt="" />. Story goes that they overheated their motor, had head work done, and then heard the lower end make a knock sound every now and then. They parked it 5 yeas ago and have done nothing to it. What do you think about that story?

I'd like a copy - this is the route that I'm seriously considering myself (unless you wanna shoot his site add'y my way).

HBinKC

I'd take a look at it, hauling along a couple of well charged batteries. I'd crank it until the oil pressure comes up on the gauge, looking for any flutter in the pressure. Then I'd take an oil sample and send it out for an oil test (search KevinC and oil test for who he uses).

This will confirm oil pressure (the pressure check is a LOT easier if you rig up a standard 60psi pressure gauge from the plumbing supply store and replace the gague sender at the oil filter with the mech gauge) and tell you if they have the expensive metal in the oil. I'd also buy a compression tester and test the compression. My guess is:

1. they may be lying pukes and it's a rod knock or main knock, but a rod knock happens twice per engine rev, should be audible at idle, and constant. A main is a much harder knock, probably twice per rev also. The bottom end on these things are very tough, and although it happens, rarely go south at under 200-250k miles. The heads last around 80-100k easy.

2. It's a misfire or the head work was done wrong and it's hydrolocking on cranking from the leaking head gasket.

The fuel is gonna be bad sitting that long, and will smell very varnishy, and probably won't run the motor.

My son bought a 91v6 5spd for $500 that wouldn't crank. We got it running by sloshing gas in the throttle body, and quickly took it to a gas station and hit it with two cans of injector cleaner and a Chevron fillup. Ran like a champ from then on. He traded it for a $2k veedub westphalia camper popup van straight up.

Wish I was closer and I'd go with you...

HB, look under username MontyMcV on the user list, and go to his listed web site for a free fsm download for your or similar model and read that. When you get ready, I'll do a "head job bible" from my old posts for the tech sticky, after all the other good mechs on here get thru peeing in the soup...

Well, it looks as if MontyMcV currently has his resume posted. I wish him luck btw.

What sort of info would I be getting if I could have downloaded the fsm (what does fsm stand for?)

I'll take a compression tester along, as well as some fresh fuel. I'll check the oil and the fluids too.

I'll let you folks know how it goes. Thanks for the info.

FSM = Field Service Manual. Has just about all the info you need to work on most issues that pop up on the truck.

I've always used it to mean Factory Service Manual in the context of Mitsu FSM's. <img src="/forums/images/graemlins/cyclops.gif" alt="" />

FSM downloads available per the link in my sig... <img src="/forums/images/graemlins/wink.gif" alt="" />