GodwinAustin

Well I should have expected this as my last two trucks have both had cooling issues. and here we go again.


I bought this 88 4runner a short time ago, it is a 22re.

Well out on a trail yesterday, got out of the truck and the coolant was boiling furiously in the radiator. Ended up checking the cap, and sure enough the cap was busted and the wasnt holding pressure. This and driving at 10,000 feet easily caused the coolant to boil. To compound this, for whatever reason the PO didnt have a fan shroud installed on the radiator I had planned on changing it soon, but being winter in the rockies I wasnt rushing to get it done.

so... after pressurizing the system I drove a bit, parked, and what do you know but a big puddle of coolant collecting under then truck.

After a bit of investigation it seems to be coming from both the waterpump and the hose that connects the pump to the lower coolant hose fixture, and its leaking alot, but only when it is under pressure.

Regardless, I am buying a new waterpump and probably just going to replace all the hoses, I may even splurge and buy some evans waterless coolant that mt goat wrote about.

I guess my question is...

assuming the truck was run for a while with an unpressurized cooling system operating without a fan shroud, what kind of life can I expect from the headgasket??

camo31_10.50

did it ever overheat?..mine only boiled when it over heated..LOL..

idk what happens at higher altitudes..but if it was boiling..that's definitely not good for your headgasket bud!

GodwinAustin

temp gauge never went past halfway, and beyond that the truck ran fine
no loss in power, or hesitation - both of which happened when my pickup overheated.

again the coolant was unpressurized and I was at about 10,000 feet.

camo31_10.50

i would say your HG should be fine...replace the necessary parts and see what happens..lol

i take it you have the stock fan?...ever thought about upgrading to an electric one..like the taurus setup..or the mercury villager?

GodwinAustin

yeah, well since i had to go in and replace the shroud, and the water pump, I was thinking of doing the taurus fan mod, but I couldnt find one near here, and when I added shipping it was just too much.


I guess I still dont understand what boiling coolant does in the short term thats so bad...I understand a coolant system works by pressurizing the coolant, subsequently raising the boiling temp, but higher boiling point or not, the coolant still gets just as hot temperature wise either way.
I understand you will lose water from the coolant as it evaporates, but as long as you refill the coolant and that steam is able to be released, where is the damage done?

Does the boiling cause the coolant to lose its effectiveness because of the smaller percentage of water?

camo31_10.50

whoa..i have no idea..LMAO!..i aint that smart (yet im only 18) all i know is that boiling coolant is bad LOL

abecedarian

When the coolant boils, it boils around the cylinders and passages in the head. Vapor / steam in those areas reduces the ability of the coolant to conduct heat away from the metal and into the coolant since the liquid isn't in contact with the metal, so the metal parts get hotter than normal.

If coolant is adaquately circulating, no significant damage should be done, but it is possible for the rapid expansion of the coolant into vapor to cause erosion to metal parts.

desertcamper67

X2 and great answer. I'm not sure but would retorquing the head help? At least give some reasurrance?

abecedarian

Retorquing shouldn't be necessary and I would advise against it.

camo31_10.50

Listen to abe!!!! He knows his shiz nizz

desertcamper67

Why is that?

Magnusian

Wasn't this exact issue on Car Talk a couple weeks ago? I think it was a '93 4runner though. I believe the suggested culprit was the water pump.

e: No, wait, boiling coolant was someone else, woman with the 4runner had a funky transmission.

abecedarian

The bolts aren't going to loosen due to getting a bit hot and over-torquing can damage more things than running slightly under-torqued.

GodwinAustin

You guys are amazing. thanks. and although there seem to be alot of threads on boiling coolant - I didnt see any threads that really detailed why the boiling was bad - and although it is obviously not good for your coolant to be boiling - its nice to actually know WHY.

So I am going to change out the hoses, add a shroud and fix the water pump and hope my HG is doing ok.

runnermedic

your problem maybe a thermostat faillure, if you dont burp the engine water and air will get trapped inside the egine and making pressure to the radiator only.if the thermostat doesnt open the water from the engine will keep heating up vaporizing the water.this will only happens with the radiator cap on,but if you loose the cap prior to start the engine the pressure will exit from the radiator,check the 2 radiator hoses for difference in temp.top hot and lower cold after engine reaching the operational temp, means a bad thermo or air in cooling system in some cases cold wheater cause thermo faillure.
well hope this can help!!!
check my mercury villager efan swap!!!

blackcat79

your problem maybe a thermostat faillure, if you dont burp the engine water and air will get trapped inside the egine and making pressure to the radiator only.if the thermostat doesnt open the water from the engine will keep heating up vaporizing the water.this will only happens with the radiator cap on,but if you loose the cap prior to start the engine the pressure will exit from the radiator,check the 2 radiator hoses for difference in temp.top hot and lower cold after engine reaching the operational temp, means a bad thermo or air in cooling system in some cases cold wheater cause thermo faillure.
well hope this can help!!!
check my mercury villager efan swap!!!


I want to thank you for this!! I have this problem!! I just changed out the head gaskets. so after reading several posts that i could be a bad head gasket i wanted to to throw up. i had a conversation with my dad about it and he think it could be the thermostat as well. gonna change it tomorrow. The one in it is new but ive had em be bad from the factory. If any one reads this pray for me!! lol