nate6145

95 4Runner 2wd 3.0 292,000 miles.
Using about a half a gallon of coolant per week. Still runs good 18+ mpg.
Changed plugs and noticed no difference in plugs like you usually see when a cylinder is taking on coolant. I have went over the entire engine and cooling system with a flashlight and inspection mirror and can not find any external leak. Under static pressure test, system will hold 12.5 psi. If you go over that it just bleeds back to 12.5 psi. I can smell a slight coolant smell when starting the engine but have no white smoke from the exhaust.

Could this loss of coolant be at the intake manifold or throttle body some how?
Also there is no evidence of coolant in the oil.

Help! I really like this Yota and would keep it forever if I could.

toynado

aluminum eating errosion making holes in water port all the way to the cylinder like in my 22re?
caused by use of hard water instead of steam distilled?
or
mix of anti freezes due to block not totally drained before adding new, different coolant?

re torque head?

ultra stretched out re used head bolts?

yes, the intake can definitely leak coolant

take off air hose and look in open throttle with light and see if it looks too clean to determine if the throttle is involved

examine radiator cuz pinhole leaks have been known to do that with no drips and little or no evidence of whitish coolant stains

use scope to examine piston tops thru spark holes

that amount of coolant will steam clean the pistons for certain

PismoJoe

Most likely a pin hole leak somewhere, could even be in the HG causing it not to smoke too bad or be extremely noticeable since you say you smell a sweet smell at start ups

tc

Historically, evidence would lead to head gasket.

Pull spark plugs

Perform static cooling system pressure check (the longer time, the better)

Crank motor, watch for coolant squirting out of spark plug hole.

metalhed

I have the same problem with my sons truck.
New head gasket, front cover, timing chain, oil pump, cam etc and the antifreeze disappears. We have been over the whole motor--nothing no external leaks, no smoke no smell nothing. Bore scoped the cylinders and it is hard to tell, since the motor was part and worked on 3 months ago.
The truck is going back to the shop that did the head gasket for another look. We have pressure tested overnight, no drop in pressure.

I would like to find an exhaust gas analyzer, and hold it over the open radiator to see if any exhaust is leaking into the cooling system, but you just dont find exhaust gas analyzers at the parts store- a pretty spending item

Plugs are coming out again this weekd end, check and see if they are showing any signs of a leak

frustrating

nate6145

Thanks for the replies.

toynado

duzn't the coolant smell like gas? or 'hydrocarbons' ?
if it leaks enuf it can hydrolock when you try to start it
my 22re did that
it didn't lock up, but it would barely turn over...

tc

Note that Toyota cooling systems are notoriously hard to get the air out of. It's pretty common to appear to be losing coolant after doing engine work where the entire system is drained.

toynado

wow
my 22re always burps itself perfectly
i do have to make sure it duzn't get too low when the thermostat first opens tho
and it'll overheat immediately if it's less than a quart low
bugger

the way it overheats if i start it with the heat on really really really grates my cheese

tc

Search on www.4crawler.com - it's a problem with your thermostat.