I have been working on my girlfriends 94 honda civic dx 1.5 liter with 230,000 miles.
Originally the car was overheating and the radiator and the thermostat seemed bad so I replaced those. The car ran good for a while until she was stuck in traffic on a hot day. Then it started overheating again, and continued overheating until it started blowing out white smoke. Also the car was burning oil and she was running it three quarts low but she says she didn't run it like that for that long. So we figured she blew a headgasket. So I took off the head and took it in to be pressure tested and they said there are no cracks but it needs a valve job and new exhaust valves. And there was a hole in the head gasket.
So we did a valve job, got a new gasket set, put the head back on, and changed the oil etc.
It's still overheating and blowing out alot of white smoke.
And it surges while it's idling or at low speeds which it did that before also.
I was thinking maybe the water pump is bad, is there a way to test the pump without taking it out, or the thermoswitch?
Or is there a way to test and see it the new gasket is leaking without taking the head back off?
Anytime the white stuff is coming out the tailpipe, you have a water problem in the cylinders. The overheating is the next indicator and the surging is related. The surging should go away when everything else is taken care of. The air in the system is causing a sensor to misjudge the temp of the vehicle and tries to compensate with modifying the fuel mixture back and forth. This is a case of either a bad head gasket (even a new one), an improper installation of the head gasket, an improper job of torque on the head bolts, or not getting the head planed. Walk yourself through those steps and figure out where to step next.