Radiator overflowing from overflow resevoir.

[Azplinker]

Need some advice. When the radiator is full and the car warms up, as the thermostat opens, fluid should come into the radiator and drain down through the radiator. If the fluid is coming out of the overflow tank, how do I determine if the radiator is not draining correctly or the radiator cap is too weak to resist the pressure?

1992 Sidekick 4dr Auto 1.6 L 16V MPI

[fixkick]

hello and welcome !

on reflection, i totally misunderstood this question.

overheating or not.?

it seems there are leak's
what are all symptoms.?

[Azplinker]

1992 Sidekick 4dr Auto 1.6 L 16V MPI

How soon after cold start does this happen?

I just replaced the radiator hoses and this was the first time I tried to completely replace all the coolant after draining.
Car has been operating for about 8-9 months without any heat related issues that I know of. I have noticed it would be low on coolant from time to time without any noticable leaks other than the occasional overflow resevoir drips or small puddle. About 7-12 minutes after cold start the temp gauge starts to rise from cold to a little past first warm indication, (1/4 of temp scale) and stays there. So no indication that this is too hot from the gauge. With the radiator cap off to monitor coolant level after filling the radiator completely at cold, as the thermostat opened up, the coolant would rise and fall until I guess the thermostat opened completely. Then, again with cap off, the coolant really started to come out of the top to the point of spurting about 6 inches high at one point. Fans, belt driven and thermostatically controlled, both work and thermostatic cycles on and off.

I will study your overheating info and replace radiator cap and buy pyro gun to check radiator effectiveness.

[fixkick]

rad full, cap off. when the thermostat gets near open nearing 150F, the hot fluid expands in volume, this is normal and the side tank catches all that (if not overfilled before)
i can see all this is minute, eye on,
cold engine
rad full of 50% AF
the caps on, now,
the side tank is on low mark with fluid in there.
the hose from rad neck to tank is good, dont leak,
the hose that point goes in side that tank to the bottom of tank , if not each cool down will suck air to the RAD. and rad will drop level ,
the coolant must not drop in the rad day by day, if side tank works it must NOT drop day by day, or you have serious issues.
yes in a month or so levels can drop a tiny bit. but the side tank covers that. lose at all times if its level mark is always never below the plastic tank marked MINIMUM.
what i dont understand in your post is the leaks thing, exactly what does leak? i think just the side tanks explodes, but i cant see it and seeing makes the case. if set up right before the test, min level, and rad full, that is steam explosion or radical exhaust gases. there.
got oil the the AF , got carbon floating on top of cap off neck , there, cold?? if yes, bingo


if the rad was full (burped.)
tank at min.
the side tank must not ever go over max. if it does, there are serious problems. (exhaust reaching rad via 2 ways, block or head jacket breaches,cracks etc)
or the pump is dead. (steel fins inside impeller, are GONE)
that is why asked if car cools ok moving fast, that proves rad works and pump works.
my guess is you can leave drive way. do to rapid, over flow of side tank.

keep in mind a dead pump causes rapid steam explosions in the water jackets fast, and will do just like you said,same with cracks in block /head or head gasket blown.
the leak down tool passing tells you the blocks ok but pump is dead. see?
each test eliminate other possibles.

one guy i know, flushed the system clean, then took off themostat housing,
and stat
then with that block and housing full of cold clean water, no AF
he started engine, (helper)
and look at the water there in the housing base.,
the water will shoot out, pump flow ,seen, so pumps not dead.
or put it all back together, with NO STAT. and only water,
then with rad cap off, start engine, now pump is on line and pumping full circle. and you look at the cap off neck FOR? EXHAUST Bubbles, now.
see those. you have A big breach to exh or compression side.

those are the only tricks besides , doing the real tests. leak down and mister GREEN/blue, that both find this breach. deal.

[Azplinker]

If Radiator is clogged or cap not sealing would the 12 psi normal pressure push the AF out to the overflow tank until fluid is low enough to flow though the partially clogged radiator?

Leaks were AF from overflow drain hose and/or broken top of overflow tank.

What is best method for flushing possible clogged radiator?

[fixkick]

the a/f freeze and the 12psi, both raise the boiling point,
but yours is not boiling, the gauge is not overheating,
low fluid helps nothing, only viscosity .
if so the side tank over fills even if you start from empty tank.
that is steam or exhaust.
there is no way to clean a rad. all the chem from long ago are not banned, all they sell now is Organic, GREEN? orange oil, and is useless.
most rad shops are gone, now remember WALTS.? its now WaLTS BRAKES. (end of brass rads, caused)
the old shops used acids to clean brass rads.
now the rads are aluminum, and acid kills one is seconds, so how can you clean delicate and thin aluminum ? now that is the $64,000 dollar question.....

do a compression test yet, for $20
if that passes., do the rad leak down test.
if that passes, its a toss, pump or rad.?
ive removed rad 2 big hoses, and run garden hose top side, and at lower end look? ,full blast pressure, and flow of hose, to see if flow is good.

[Azplinker]

the a/f freeze and the 12psi, both raise the boiling point,
but yours is not boiling, the gauge is not overheating,
low fluid helps nothing, only viscosity .
if so the side tank over fills even if you start from empty tank.
that is steam or exhaust.
there is no way to clean a rad. all the chem from long ago are not banned, all they sell now is Organic, GREEN? orange oil, and is useless.
most rad shops are gone, now remember WALTS.? its now WaLTS BRAKES. (end of brass rads, caused)
the old shops used acids to clean brass rads.
now the rads are aluminum, and acid kills one is seconds, so how can you clean delicate and thin aluminum ? now that is the $64,000 dollar question.....

do a compression test yet, for $20
if that passes., do the rad leak down test.
if that passes, its a toss, pump or rad.?
ive removed rad 2 big hoses, and run garden hose top side, and at lower end look? ,full blast pressure, and flow of hose, to see if flow is good.


Bought new Cap. Old cap was missing Vacuum breaker and was stamped for 13 lbs. New cap is stamped 16 lbs. Is 16 lbs wrong? ReFilled radiator and max of overflow reservoir. Started and idle ran for 20 min. Reached 127* F at stat housing. No loss of fluid or overflow. Shut off engine and housing went to 202* F. Top of radiator at 202* F. Overflow tank squirting some AF but not a lot, noticed AF seeping out of top seem of radiator. Have I destroyed radiator by using the wrong rating cap? Thanks O'reilly.

[fixkick]

what thermostat is in car, 180, 193, 195F? they have 3, I run 195fs, for max mpg, and better cooling, but stock and EPA legal is 180f. what is yours.?
50% Antifreeze a must. have that? not over 60% or cooling is less. !!!
16 psi is too high. 12-14 i think is spec. finding caps can be real hard, if the rad was ever changed out to china made rad. seen that many times.
but 2 psi over will not damage any system. (not frail, or ready to fail as most are.......)"straw that broke camels back day"

is this RAD in (was sold day 1 from CAMI with "Harrison" RAD from Canada plant, with alum core and black plastic top ) still stock?
the Rad is bad, all are if stock, no stock rad of above type runs for ever. and for sure, not 23 years ( a Guinness record here?)

but you started from full at rad. and the rad leaks, so that means the top rad hose will never hold 12-14psi pressure, full time,
and means the top Rad hose never gets HARD, like all cars must do. hot.

that means this rule is wrong. 260

[fixkick]

see my newer slam dunk section, i tied to get them all ... not easy and many 20yo, cars fail 2 or 3 here.

http://www.fixkick.com/overheating.html


see the hill billy section too, on wild tests. and why, it can work.

you got leaks, there is not getting past those.... a doom thing that is.(for sure in summer , up high on a mountain)

[Azplinker]

Thanks for all the help and guidance. Trying to understand what is happening with this vehicle. Timing is good: 8-10 * advance. Runs fine as far s I can tell. A little underpowered , but without another one to test with it's hard to tell if there is really a problem. No bubbles in RAD, No oil in AF. No AF in oil or transmission fluid either. Idle seems to work correctly. 1200 rpms until it warms up, then down to 800 after that. Temps steady and doesn't overheat sitting at idle or on the road. Haven't tried pulling a long hill though. Wondering now if I overfilled AF because I forgot that not all AF in engine will drain from petcock. Think I got about 1/2 gallon or so when I drained it. Book says 10.7 Pints for capacity with automatic. That's about 1 and 1/4 gal. Hard to measure when it won't all drain out. Should the fluid always be at the top of the radiator or just watch the level in the overflow resevoir? Maybe the thermostat is a little slow to open and the RAD cap was bad without a vacuum seal[/size]. Have to wait for more time to pass as this is 19 yr old son's car and he doesn't drive it very far most of the time. I'm watching the AF in the overflow resevoir after sealing the RAD cap back on and will try to decide if I need to do the compression check or change the thermostat.