akacoke

Hi, my civic d15b7 wasnt passing smog test for couple times, i thought the headgasket was leaking, so my friend owns the smog shop did the sniffer test on the radiator with cap off, there is 0 HC , i know that usually means the headgaket is fine, now the car passed smog check after valve adj, new O2 sensor and sea foam, everything is running perfect, idle smooth. i did a visual inspection of leaks, found no leak. i dont have to add any coolant what so ever. i never have any hard time starting the engine, every time i crank the engine i try to listen, the rhythm is smooth and even the car never over heats, i know the ECT sensor is working correctly.

its just some tiny lil bubbles and big ones are like 1/10th inch 2/10th inch ones comes out from radiator sometime, after thermostat opens it doesnt come very often its like every 30-40 sec 6 7or small bubbles would come out. is this normal? i only had the cap off for about 6-8 mins. so right now it could be not doing it at all.

im a mechanic student, im just trying to learn and get everybody's opinion

akacoke

i just did some more research, can anybody confirm if its a bad radiator cap?

MegasXLR

Bubbles are just air in there... usually you wait until the fan comes on before you put the radiator cap back on.

akacoke

thanks for the input, i know its air, im not asking how to bleed or put on the cap.

but how is it gotten into the systerm? i wanna find if the cap is the cause of air getting into the cooling systerm

lazlong

Pressure test the cap and system. Google for coolant or radiator pressure test. Youtube has some decent videos.

motegicivic

If you want to play it safe get a new cap, pretty cheap. As for it letting air in, hard to say I would doubt it.

akacoke

imma test the cap at school, but im pretty sure its not sealing properly, cuz i caught some coolant sitting on top of the cap coming from under the sticker.



i asked the my teacher and other classmates who're working techs, they all confirmed that if the cap its not sealing air would be sucked in during engine cooling down


i just bought a new cap from my local honda dealer, its like 14 bucks. not bad tho. thanks for your guys help, i appreciate it.

motegicivic

Compare the old to the new, the old one might be missing the rubber gasket.

I bought a new cap and the rubber gasket had come loose within a year, I had the old one in the trunk and used that. Both Honda caps.

akacoke

i checked nothing is missing or cracked on the old one. i guess the new parts quality is not really as good as old parts

motegicivic

Pisses me off, the damn gasket detached and was in the neck of the radiator, doesn't go on right, so I used the old one for now.

akacoke

theres 1 year warranty on the cap

motegicivic

Over a year old unforuntately.

akacoke

i would just bring that broken one to them, they might just give you a new one, or its only 13 bucks, at least thats what i paid, you dont want a 10 dollar part to messup your engine