Unable to bleed the cooling system.

[nighthawk57]

To make a long story short,i own this cb for 2 months and when i got her the previous owner seem to have use some sort of radiator stop-leak to temporary fix the radiator.

So i changed the rad and flushed the coolant since it was very dirty.

The temperature gauge was kind of low and my heater was not pulling enought heat so i changed my T-stat with a auto part one.Nothing changed.

I read on here that honda have issues with non OEM one's so i replace it with a genuine one.No result.

The problem is that now,i don't get more heat and i can't bleed the cooling system.When i start the engine,the cooling rinse right out of the rad so i have no choice but put the cap back on.The engine is cold,so i don't get it.Can a OEM T-stat be faulty?

The lower rad hose is cold,and the upper is hot.The lower one tends to get warmer toward the engine side.

Now this week-end,i want to take a last shot at it before the cold settle in.

What is the right procedure for flushing the heater core?Can i simply unplug the hose at the heater valve and the other side inlet and plug a garden hose?

Since i found large residus inside the T-Stat housing,how should i flush the engine without damaging the water pump?

http://www.cb7tuner.com/vbb/showthread.php?t=144444

Thanks everyone for your precious helps and hints so far

[mj213]

Wonder if you can just let it run for a few minutes even if it's overflowing. Chances are there's an airpocket in the system causing the overflow. Of course if it gets warm it'll overflow anyway.

[accordztech]

if the top is hot the lower one is cold ur thermostat is bad.

BUT!

if it never had a chance to open you wont know. So do this,

make sure with the engine cold that there is enough coolant in the radiator.

then put the cap on.

then there is a bleed valve right on the thermostat housing, kinda looks like a brake blleed screw. losen that TURN THE HEATER ON HOT AND RUN THE FAN and start the car

you will see bubbles comming out then when its pretty much fluid close it.

let the car heat up. after 10 minutes the radiator hoses should be about the same or at leasat getting somewhere. In the meantime keep monitoring the temp from inside the car.

if ur top hose is hot but the bottom stays cold your thermostat is bad. Report back.

also if you never did before, get a new radiator cap. Old ones tend to not hold much pressure lowering the boiling point of the fluid.

maybe use those aftermarket flush fluids to flush out the system, then flush again with water then add coolant. Right now kregan has a sale 2 gallons for 10 bucks for coolant.

[nighthawk57]

if the top is hot the lower one is cold ur thermostat is bad.

BUT!

if it never had a chance to open you wont know. So do this,

make sure with the engine cold that there is enough coolant in the radiator.

then put the cap on.

then there is a bleed valve right on the thermostat housing, kinda looks like a brake blleed screw. losen that TURN THE HEATER ON HOT AND RUN THE FAN and start the car

you will see bubbles comming out then when its pretty much fluid close it.

let the car heat up. after 10 minutes the radiator hoses should be about the same or at leasat getting somewhere. In the meantime keep monitoring the temp from inside the car.

if ur top hose is hot but the bottom stays cold your thermostat is bad. Report back.

also if you never did before, get a new radiator cap. Old ones tend to not hold much pressure lowering the boiling point of the fluid.

maybe use those aftermarket flush fluids to flush out the system, then flush again with water then add coolant. Right now kregan has a sale 2 gallons for 10 bucks for coolant.

Thanks for the quick response

I will try this on saturday and follows all the steps.If it dosen't work i will return it to the dealer.

I did a Flush with some prestone cleaning stuff and it worked great!Now my coolant is much cleaner.The rad cap is brand new and came with the rad.I will post back after with result

[Gummiegorilla]

You should always test a new thermostat before putting it into your car. Do this by placing the thermostat in a pot of water and putting that pot of water on the stove and bring it to a boil , if its bad nothing should happen , but if its good you should see it start to open also if your going to do a complete flush of the cooling system you should open the block drain plug just next to the oil filter and get the excess coolant outta there before flushing it, and like accordztech said dont forget to loosen the bleeder screw on the thermostat housing until a steady air bubble free stream starts to flow. hope this helps a bit I just did a bunch of cooling system work myself a couple weeks ago.

[nighthawk57]

You should always test a new thermostat before putting it into your car. Do this by placing the thermostat in a pot of water and putting that pot of water on the stove and bring it to a boil , if its bad nothing should happen , but if its good you should see it start to open also if your going to do a complete flush of the cooling system you should open the block drain plug just next to the oil filter and get the excess coolant outta there before flushing it, and like accordztech said dont forget to loosen the bleeder screw on the thermostat housing until a steady air bubble free stream starts to flow. hope this helps a bit I just did a bunch of cooling system work myself a couple weeks ago.

Testing the T-stas is defenatly the first thing i will do this w-e,and next time i changed one.Thanks for the tip

[Gummiegorilla]

one thing that also i forgot to mention was always use a new thermostat gasket when replacing the old one to prevent leaks.

[accordztech]

one thing that also i forgot to mention was always use a new thermostat gasket when replacing the old one to prevent leaks.

i never used it, usually the rubber ring around it is fine.

but it never hurts.

[Gummiegorilla]

i never used it, usually the rubber ring around it is fine.

but it never hurts.

yeah thats what i was talkin bout sometimes ive gotten new thermostats outta the box that didnt have the rubber gromet that goes around it, and I had to buy one seperately.

[nighthawk57]

i tested the T-stat and you guys where right it is stuck close...the guy at the honda dealer replace it and as soon as i get my car back from the shop i will change it.Thanks for your help!

btw,the rubber gasket came with the oem one.

[browneyes]

none

note: also check to see if your heater cable is on the water valve

[Teddy]

hi i think your cooling system might be pluged. i`m new to cb7 but i know cooling i would back flush the moter . put a hose in the top rator hose going to the moter and remouve the thermast and the hose, the water should come out with a lot of old stop leak . i don`t know what will hapen to the water pump or if this is the way to do it ..sorry .. good luck... also could your radotor be pluged ? if you put water in the top does it come out the botten of the rad sorry i can`t spell

[kentucky accord]

hi i think your cooling system might be pluged. i`m new to cb7 but i know cooling i would back flush the moter . put a hose in the top rator hose going to the moter and remouve the thermast and the hose, the water should come out with a lot of old stop leak . i don`t know what will hapen to the water pump or if this is the way to do it ..sorry .. good luck... also could your radotor be pluged ? if you put water in the top does it come out the botten of the rad sorry i can`t spell

either the t-stat or air in the system. easiest way to get that air out is to raise the front of the car with a jack, remove the rad cap, and start the car.

remove the t-stat all together and run the system to see if it cycles through.

[speedracer450r]

also be sure the t-stat is installed with the weep hole as close to the top as possible to allow air to come thru if its at the bottom it won't breathe so to speak

[HondaFan81]

Drain your coolant system.

Inspect your radiator cap, if it is not sealing properly, replace it. Your coolant system is and needs to be at 16 psi, which is critical. If radiator cap is degraded and does not seal properly, it can not do that. Replace with new if so.

It seems like your heater core could be plugged up with debris or that junk the previous owner put in your coolant system.

I would remove the inlet heater core hose at the water pipe (near water pump, driver side fender). Then, remove the outlet heater core hose (attaches to cyl head on passenger fender side, under distributor).

Stick water hose on the inlet heater core hose and flush it out. If there is any debris, it will obviously come out the heater core outlet hose near distributor.

I'd remove the Tstat and reconnect all hoses. Fill your coolant system with water, bleed and let engine run, to flush itself out. Drain all water and reinstall Tstat.

Finally, fill the system with coolant and follow procedure.