my nissan sunny's readiator has oil mixed in it. and its engine oil is very much brown muddy color. is my gaskets damaged? it is also diffult to start my car at times. what might be the problem?

You are correct in saying a gasket has Failed

The Sunny engine is prone to head gasket failure. The old Cherry Model of which I had 2 cars, had the same engine, and Head gasket problems.
A common error when fixing the problem is Not to use a torque wrench to tighten the Cylinder head bolts evenly. Thus the head expands when the metal heats up and the leaks continue
Doing it by guesswork on this engine is not recommended
Hope this of some help?
And welcome to Answerpool

I have an '86 Dodge model 600 with the same problem. One thing I discovered is that the Oxygen Sensor(s) are often damaged when a head gasket is leaking. I have determined that my car is not worth fixing, but since it is still drivable, I'm keeping it until it just won't run any more. I did just replace the Oxygen Sensor to correct a frequent stalling problem.

See this page, perhaps it will help.

Dwight

thanks guys your advice really helped.
i replaced new head gaskets and now my car is ok. i was just wondering does gaskets get damaged when an engine boils? or how else could it happen? and what r the other complication if an engine over heats?

quote:

"What do I do if my car overheats — and what's the worst thing that can happen when it does?"

This is the site where that question was asked and answered below. A lot of good information about cars is on that site.

Your vehicle's engine generates enough heat to melt steel. If too much heat accumulates, the engine can be damaged in a number of ways: the metal cylinder head can warp or twist, the layer of insulation called the head gasket can burn away, and internal parts like pistons and their connecting rods can warp or crack. The worst thing that could happen is the engine "seizes" — meaning the pistons actually melt into the cylinder walls — never to move again. If your engine overheats, turn the heater and the fan on high to help get rid of the heat. If that doesn't help, get your car safely off the road, turn off the engine, and let the engine cool down.