Jimi Hondrix

1998 Civic EX coupe. AT, 148K miles, stock D16Y8 w/Vtec

My daughters car overheated last week and I finally got time to make the three hour drive to her place to repair it. Turns out the heater hose that connects from a control valve near the firewall and connects to the block near the ECT (under distributor) had a split in it. I also replace a bypass hose as it felt like the hose wall was weakening near one of the block connections. Both hoses shown here: http://repairguide.autozone.com/znet...528006178a.gif

After replacing the hoses I filled the cooling system with water and parked on an incline. Put a funnel in the radiator opening, set cabin air to max heat/recirculate (fan off) , bled air out for 15 minutes while occasionally revving the engine and filled with water when necessary . No, leaks noticed, dash temp gauge in good range, no overheating.
Drain water through stopcock, refilled with 50/50 water-coolant, and repeated air bleed procedure shown in manual. Took for the car for a half hour drive and all was fine.

Drove daughter's car back home (3 hours) last night and check the radiator this morning (when cold before start-up) and coolant was low. It need about 3 or 4 cup of coolant mix to top it off..is this normal?

tony_2018

Its not normal but it could be because you probably didn't bleed out all air.

Jimi Hondrix

I know that a bad head gasket can cause coolant loss.
Both times that I bled it ( water only. 50/50 mix) while revving engine there were only tiny or no bubbles present. However, at idle and especially after revving there were bigger bubbles but, coolant did not spurt out much at all past filler neck. Engine oil looks good..no milky appearance. No white smoke or sweet smell from exhaust. There is a small amount of water present in tail pipe but, from what I've read that is not uncommon for any car. Car seems to run fine.

Does the coolant system bleed more air out to the reservoir on it's own?

Former User

Yes, it can.

Only worry if you must add coolant after every drive. Also note that the coolant level in the reservoir rises when the engine is hot and drops when the engine is cold. This is also normal.

Because you added water to the cooling system, you should drain and refill with 50:50 a few more times to get all the corrosive water out of the system. Alternatively, remove the block drain bolt and drain all the coolant from the system and refill with 50:50.

And the service manual has better coolant hose diagrams:

tony_2018

+1

Probably the boiling water is adding pressure to the system?

Jimi Hondrix

Thanks Ron..I would have normally used distilled water and mixed it with coolant. I didn't have any distilled water available.. so I will repeat the process as you suggested.
I should have got premixed but, it seems overpriced, especially if I needed more than a gallon (in case of a leak). I didn't know the block has a drain bolt..glad you mentioned it.

TomCat39

I'm not sure why others would say it's not normal.

I find every time I bleed my system, the next day I need to top up the reservoir. Then after that, it's all fine and dandy.

I fill the resevoir and the radiator after the burping process and shut the car off while it's still hot. Close everything up and the next morning after the car has fully cooled off, my resevoir is always low. I top that up and then I'm good to go until the next time I do coolant stuff.

Is my situation odd and different of everyone else's?

Oh wait, radiator low...... Yeah my rad is never low, just the resevoir. Sorry can't read. Please ignore.

In your burping process, after you shut the car off, did you top up both the rad and resevoir to full marks (resevoir) and bottom of filler neck (radiator)?