I have a Titan 2008 pickup and oil is in my radiator. What happened? What could of caused the oil to go to the radiator?

A low freon level will cause the compressor to not operate by not grounding the relay. Some Nissans also use the heater motor resistor to make the relay operate. If your heater speeds do not function on all settings the resistor could be the problem

If you are taking on such a huge job as a head gasket on a Titan, why oh why didn't you MARK EVERYTHING.

Several things,check your oil,serpitine belt,clean you radiator(flush). Thermostate..

put the thermostat back in the right way . Check and replace the bottom radiator hose if it feels soft when cool. Old soft hoses will suck together at speed and slow down the coolant circulation. Have a flow test done on the radiator cores for partially blocked radiator.

you have most likely blown a head gasket or cracked a head

It needs to be scanned by a code reader or scanner to realy find out the problem.

check the reservoir and the overflow tube for cracks. also followq the hoses, and see if one is leaking, and the coolant running down the rad. hope this helps.

From the 2004 Titan Factory Service Manual, You can get one Promanuals. I hope this helps. It's straight forward procedure.

1. Drain engine coolant from the radiator.

2. Remove air cleaner and air duct assembly.

3. Disconnect A/T fluid cooler hoses.
(Install blind plug to avoid leakage of A/T fluid)

4. Disconnect radiator upper and lower hoses from radiator.
CAUTION:
Do not allow coolant to contact drive belts.

5. Remove the lower radiator shroud.
( Release the tabs, pull lower radiator shroud rearwards and
down to remove.)

6. Remove the radiator shroud upper bolts and remove the radiator
shroud upper.

7. Remove the A/C condenser bolts and brackets.
NOTE:
Lift A/C condenser up and forward to remove from radiator.

8. Remove A/T oil cooler bolts and oil cooler from radiator and
position aside.

9. Lift up and remove the radiator.
CAUTION:
Do not damage or scratch air conditioner condenser and
radiator core when removing.

That service "Expert" who told you that should probably get his head checked or his *** kicked. The radiator has nothing to with the stereo system. Although and I dont think this would be the situation at all, its possible if you have an amp hooked up, its drawing too much off the alternator but that would be drawing current off the battery. It's not the stereo, I think it's second rate material that they are making everything out of these days. It goes bad so you have to take it back to be told your stereo is causing it. Hope it helps.

control head is it still warranty?