91 civic - tough question about cooling

larson.joshua · 2006-06-16T03:33:13+00:00

first i'd like to say thanks to the great people on this forum for allthe help they provide.i've done a search for my problem and i've found some things butnothing exactly fits.i recently performed a head gasket job on my civic. i began this jobbecause i had bubbling in my coolant resevoir after driving for awhile. i also had some electrical issues, but i don't see those asrelated to the bubbles. the bubbling was not boiling. some kind ofgas was pushing through to the resevoir, and i assumed it wascompressed gases of some kind coming from the cyclinders through thehead gasket.after removing the head, i took it to the shop. they told me the headhad to be machined by 6 thousands to remove the warp, which seems likequite a bit. he also pointed out where the likely breaches of the oldgasket were.i cleaned and lapped the surface of the block. there was no apparentcracking or warping (i checked for warp with a quality straight edge inmultiple directions).put everything back together to spec.i filled up the cooling system, on an incline with the radiator high.bled the system according to haynes.i've been test driving it for several days, and what happens is alittle weird. after a light drive, i get a few minutes of bubbles(again, not boiling - bubbles) and i can hear coolant sucking past therad cap in pulses. after a heavy drive i get the coolant pulsing, butmuch more bubbling - like the bubbling i used to get.the only thing i have found that i didn't do was crank on the heaterwhen i was filling the cooling system. is it possible that since i didnot do this, there was a chunk of air in the heater core that is nowescaping when the car heats up? i ran the car tonight at idle with theheater on full blast after discovering this possibility, but the radstayed full (again on an incline) even with the bleeder open.it seems there are three or four possibilities:1 - block is cracked2 - head is cracked and crack missed by shop3 - heater core had air bubble and now air is...

Jun 16, 2006 21 Replies

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jim beam 20 years ago

it shouldn't be machined at all [or at least, not with "traditional" gear] for the reasons stated. it just needs to be lapped on a properly flat rigid bed.

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Monster 2269 20 years ago

Radiators are relatively soft. I once saw the neck of the radiator had become "out-of-round", causing several new radiator caps to blow air bubbles into the puke can because an effective seal was not formed. A new radiator fixed the problem. You might check for gunk build-up in the neck which could cause an incomplete seal.

Later, Ralph

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