rb240sx

I did a search but didn't find exactly what i was looking for.

Back Story

The car began overheating on my girlfriend start trouble shooting she tells me the heat just blows cold air.

I pull the thermostat put in boiling water doesn't open. Replaced bad thremo the cars temp will fluctuate from running right in the middle to the red and will bounce from on to the other in a matter of 30 seconds.

I believe i still have air stuck in the system after bleeding

Steps taken to bleed

i removed the reservoir cap

cracked the bleeder valve on the top of the throttle body

the car comes up to temp both lower and upper radiator hoses get hot the upper being hotter but not much

rev the engine at around 2500 rpm

small bubbles come out around the bleeder bolt the reservoir began to spit coolant out what i think is burping.


The cars heat will now blow really hot sometimes then go back to blowing cold.


I thinking air still in the system.

is there a trick i am missing on burping the system?

rb240sx

Put a new reservoir cap as well.

rb240sx

Okay finally got the system burped thermo holds steady right in the middle after a 10 mile run. the heat is also working not at idle but i belive this small pockets of air still. These should bleed out on there own thru the res tank correct?

LScowboyLS

the car will self-bleed if you install a new Toyota radiator (reservoir) cap and make sure that you have the jiggler hole in the thermostat positioned at 12'oclock so that the air bubbles can escape.

then, after making sure the system is full at the FILL BOLT (behind thermostat housing or on top of throttle body depending on year) - make sure the overflow reservoir is filled to the max line and continue to top up after repeating hot/cold engine cycles over upcoming days

PureDrifter

iTrader: (10)

no. they don't.

'98-00 at least do not "self-bleed" as the highest point in the circuit is in the throttle body, not the coolant overflow.
afaik the '98-00 FSMs concur.

LScowboyLS

yes, 98-00 is also self bleeding - all they did different from 90-97 is relocate the fill bolt to the top of the throttle body - I have added this additional location info to my earlier post

please study the factory procedure shown here

cars that you truly have to manually bleed will have a bleeder valve at the highest engine point, my old Honda has one

self-bleeding means all you have to do is repeated hot/cold cycles and adding coolant, conventional bleeding of a cooling system involves cracking a bleeder valve at highest engine point

OKSTANCE

so no one things it could be thewaterpump since it has a new tstat??

PureDrifter

iTrader: (10)

lol doesn't say "self-bleeding" anywhere. In fact it says the following:
So if you leave ANY substantial amount of air at all in the system at this point it will leave a bubble and you will have a fun time getting it out.

Better practice is to fill from the throttle body, fill the reservoir/expansion tank, start the car and let it get warm, top it off THEN close the throttle body bolt and tighten to spec.

LScowboyLS

once again:

self-bleeding means all you have to do is repeated hot/cold cycles and adding coolant, conventional bleeding of a cooling system involves cracking a bleeder valve at highest engine point. Toyota doesn't use the term "self-bleeding" (not sure if their is a correct Japanese translation), but the procedure they describe is a self-bleeding system - the old Honda and other systems where you crack a small "bleeder valve" and wait until it squirts all coolant and no air are conventional manual bleed systems.

PureDrifter

iTrader: (10)

buy a '98-00, leave a nice fat air bubble at the throttle body, and try to "self-bleed" it .

LScowboyLS

there is nothing wrong with opening the fill bolt at the top of the throttle body and ensuring that there is not an air bubble trapped there, the Toyota cooling system design assumes that the throttle body filler area is full to the top.

so we are probably somewhat in agreement here, more so than it sounds like.