It's looking increasingly likely that I have seepage between one or more cylinders and the cooling system. I say this because when the car initially starts (fist 30 sec or so) the tailpipe shows nice and clear exhaust but then a continuous white plume comes out and never stops even after car has reached temps an d been driven awhile. Not only is there the white plume but plenty of water vapor too since a big puddle forms under the muffler/tailpipe. At times, the white plume from the tail pipe eased a bit but never recedes.

Removing the radiator fill cap (when engine cold) I did a cooling system bleed even though there was no reason to think it was needed, or so I thought. Once engine was at operating temperature I notice the coolant level constantly fluctuated slightly as seem from the open radiator fill port. There was a descent amount of large bubbles that bleed off the open radiation fill port at first, then there were no more large bubbles but then there were these very small bubbles clustered in waves. These waves of small bubbles kept happening so I finally just put on the radiator cap to let pressure built and drive the car a bit.

It started happening, when driving the car, high pulsating idle surges (1000 to 1500 rpm) anytime the accelerator pedal not pressed. Funny thing is that if I let the car idle before doing any driving it idles fine for as long as I let it, but once driving begins the idle does the crazy pulsing I mentioned. Since I believe to have a blown head gasket may it be possible that this idle problem is tied to it? I'm thinking that the cylinder gases are entering the cooling system and because the IABV is the highest point in the cooling system that air pocket forms there and causes the valve plunger to stay open slightly causing the high pulsing idle?

Any thoughts are welcome!

I've driven this 91 Honda since 2003 with no headaches, been a wonderful car (fun to drive too!) and since Dec 2018 when I stopped driving to do clutch plate change and some other stuff...problems seems to creep up that leaves me uncomfortable driving the thing to work everyday. Aiaiai...I can't believe I still haven't got this car fixed and now looks like it needs a new head gasket so that's gonna be another big job that will take me weeks.

Dave

 

Pull the spark plugs and check for coolant being burnt in the combustion chamber. A cylinder that is leaking coolant will usually have a spark plug that is very clean, sometimes even looking like it has been polished/wet. this is due to the steaming effect that burning coolant in the engine has. They may also have a sweet smell to them, some say it is similar to a fresh cut cedar smell. that is coolant.

Another way to test would be to do a coolant system pressure test. I'm not 100% in your area but you can usually rent, borrow a tester from a local parts store, or pick one up for fairly cheap and sell it when you are done.

As far as the surging idle, yes, air pockets around the ECT sensor or IAC, FIT valves can cause this.

 

Good info there Ghost. I already know there is coolant entering the cylinder(s) because there is always white smoke coming out the tailpipe even after can has been driven/idle for 20 minutes. There is small air bubbles in the coolant and the expansion tank is being drawn down a good amount each time I take a cold reading of it and there is the idle surges once the car starts driving. To me this is definite that coolant is being combusted, or can there be another explanation?

By the way what are the FIT valves? What does FIT stand for?


Dave