Need opinions

I just bought a 2005 Tacoma 4.0L 138k miles and I noticed heat starts blowing cold intermittently at idle and blows hot again the second I touch the gas. Took it back to dealership where they pressure tested it and everything checked out fine heat was working normal after I topped it off and bled air out. For a few days and last night it started blowing cold again, so I checked fluids antifreeze level is normal dipstick is clean however I found moisture in the threads of the oil cap is it related? Any advice or opinions welcomed.

 

Welcome to Tacoma World. The water pump pushes coolant through the system, and for heat to work it has to flow through the heater core. It could be that the water pump isn’t doing its job any more, could be the heater core is partially blocked, or could be something else entirely. Moisture in the oil cap could be due to not getting warm enough / only driving short trips, but can also be a symptom of other not so fun things. Unfortunately no way for us to tell over the web so you’ll either have to start diagnosing yourself, find a mechanic friend, or take it somewhere. Good luck.

 

Thank you was just trying to figure out if they could possibly be connected as milky residue would indicate a serious problem such as head gasket, intake ect if I have a leak would it be possible for air to get into the cooling system causing the intermittent loss of heat or unrelated? Unknown if It leaks antifreeze it was low when I first noticed and had to add to it for a few days but appears to remain stable now. As for travel I drive 30 minutes average per trip.

 

Welcome to TW! Good luck!

 

Maybe check that plastic coolant pipe under the intake isn’t cracked.

 

Well update truck was taken to dealership. I advised them I believe it has leaking head gasket or intake gasket, they called back few days later to tell me there's air getting into the system even tho I told them that when I dropped it off so they replaced heater core got truck back today problem remains so ill be calling them back tomorrow keep in mind I haven't even made a payment on it yet 05 Tacoma will update.

 

Hi there