1994 Honda Civic Surging idle

UNIBUY

MEMBER
1994 HONDA CIVIC
4 CYL
FWD
AUTOMATIC
229,000 MILES

I drained the coolant from the engine to use some engine block sealer as the coolant is leaking into the engine and blowing out the tailpipe in clouds of white smoke.
I drained ther rad, and filled it up with water. When I started the car again (to blend the water and remaining coolant), the engine started surging about 2 minutes after I started it.

I have filled the rad up, but cannot understand why the engine is now surging everytime. I hesitate to do the repair when the engine is operating like this.

Could it be an air lock/pocket? If so, how do I remove it?

Thanks.

(car is getting tired, but worth the $10.00 bottle of sealer, if it works)

3 Replies

F4I_GUY

MECHANIC
3,302 POSTS

Okay first of all, that stuff you put in the coolant is not going to repair your headgasket whatsoever. Infact, it's going to do more damage than good by clogging up the heatercore and the radiator.

Now, with regards to your problem. You have air bubbles in the system still. Your ECT (coolant temp sensor) is reading improperly because of all the air in the system thus creating a surge in the idle.

Or, it also may be IACV or FITV related as well. They both have coolant lines going to them as well.

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Tuesday, May 19th, 2009 AT 4:11 PM

UNIBUY

MEMBER
2 POSTS

Sounds like it is ready for the big scrapyard in the sky.

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Wednesday, May 20th, 2009 AT 7:46 AM

SOYSAUCESAM

MEMBER
1 POST

I am not sure about the engine block sealer issue,
but as for the air in the coolant system, this is what I had to do to get it out of my 97 civic.

Start with the car cold, and fill the radiator all the way up. Leave the radiator cap off.
Turn the car on and put the heater on full blast. After a few minutes you should see it start belching away. Mine kept bubbling for about 5-10 minutes (after the car got up to operating temperature and the thermostat opens).

You can tell once its done getting the air out because the bubbles change from big, air bubbles to smaller bubbles- where it looks like the coolant is boiling.

Hope that helps! This got rid of the idle surge for me.

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Wednesday, May 27th, 2009 AT 2:55 PM