not a blown head??

[rockcrawler31]

hey guys

had the shop test my 1HZ. thought the gasket or head might be screwed because it was blowing the water in the top radiator tank as well as the overflow and was sitting slightly higher temp than normal. was also getting froth in the coolant when filled up. We did a CO2 gas test which showed no compression getting into the coolant, so it may not be the head or gasket after all. We are replacing the rad cap and thermostat, but if that don't fix it any ideas what it may be? Don't want to go through the rigmarole of doing a head if it dont need it.

[morkz]

try the toyo section other people in there will have more info for u rather in general tech

[Zeyphly]

might sound stupid but have you replaced your thermostat in the cooling system.

[rockcrawler31]

yeah, doing the thermostat currently, but had initially ruled it out as a stuffed thermo shouldn't make you blow water

[bad_religion_au]

have you replaced the radiator hoses. a mechanic friend of mine once told me a story about his falcon that was doing similar to what you describe, he tested the head and head gasket, the thermostat and all that, came back empty handed, so his ego challenged, he just started throwing parts at it, new head and head gasket, thermostat and radiator cap, still doing it.

it turned out part of the inside surface of the radiator hose was loose, and acting as a diaphram, occasionally building pressure until it'd release it by blowing water out of the overflow.

now it's a long shot, but radiator hoses aren't too expensive...

[dumbdunce]

start with the easy easy stuff - is the radiator cap any good? and get an aftermarket one, the toyota ones are crap.

1HZ's aren't known for blowing head gaskets even if overheated so it's not likely to be that. the thermostat will probably only be bad if it has been overheated. the toyota radiators aren't spectacular and if it has over 150,000km on it it might be time to think about a new one.

[rockcrawler31]

cheers guys

i have heard that while the gasket is uncommon, the weaknes is cracking in the head itself. Having said that i think i will try all the cheap stuff first.

thanks for the hoses tip too...

MILO

[up2nogood]

There is a couple of tests a good mechanic can do which will see if you are leaking exhaust into the water galleries.

One involves a fluid colour change test at the radiator and the other is a leak down test to see if the cylinder loses pressure too quickly.

Ring around and see who can perform these for you, it will save a lot of stuffing around.

[skootin]

More than likely the head. Head gaskets do blow often. And the top of the block also gets low spots between the cylinders. Have just been thru exact same problem with customer.