Lb7 head gaskets?!
 

Had some issues with my temp guage at first not staying as warm as it used to. Round 185 but the needle seemes to bounce around a bit. Changed thermostats and no change.. Truck has 281,000 on it... With efi live ppe boost valve... New reman turbo and built transmission... Is it worth to pay for the head gasket replacement. Or should I sell??

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And how do I confirm head gaskets are bad?

is it using any aintfrez?

No and I don't notice the system pressurizing either. I recently put a new coolant sensor and thermostat in. But i noticed every once in a while it will ever so slightly smoke white at idle... During the daylight I can't see it. Only at night with headlights behind me

how meany miles on your injectors the "smoke" could be haze aka raw fuel from worn injectors. also is it making oil?

185 seams quite normal. the LB7s seem to be the coolest running duramax's.

gasket issues typically result in the engine drinking coolant or excessive pressure building in the reservoir.

i agree with walker, the white smoke at idle is probably just worn injectors. mine doesn't hardly ever get over 185 unless i'm really making it work hard. it won't take long for the coolant reservoir to get dark on the inside. if theres no pressure,no loss of coolant, not much white smoke, and the tanks not dark i would think it could be the gauge itself.

Don't worry about seeing the "little white smoke in the head lights" its just diesel smoke nothing to worry about. The only time you should be worried about seeing white smoke is if your driving and you have white smoke coming out of your exhaust, otherwise your fine