Hello Scotty. I'll try to be on point. 2007 Toyota FJ. About 18 months ago I replace the spark plugs. #6 cylinder started fouling. Also noticed that when I warmed up vehicle in a cold morning interior would be cold until I started to drive, then it would heat fine. Noises also in the dash started to appear. My coolant was low at times. I thought it was coil pack so I changed, but wasn't the issue. I also noticed if I turned engine off and restarted it would go away. This kept happening. I took to dealer, they said blown head gasket on #6 with a price tag of 4-10 thousand to fix depending on cause. Well I did not have the cash so I just kept driving and adding coolant. My oil is fine, no coolant mixed in. Generally FJ would foul slightly when I stated it up but clear up within a few seconds and run fine. I just cleared codes when I needed to. 12 months later I had the cash to replace head gaskets so I was going to do it myself; I'm an A&P mechanic. I decided to go to O'Reilly and rented a tester for combustion gases in the coolant. Test was negative, not indication of head gasket leak. FJ is no longer fouling either... I'm seriously confused now. Now I am losing coolant and the FJ cabin will not warm up until I start to drive even though I have let it idle for 15 mins and temp is up. SO if I really make sure coolant is topped off, the cabin heat is fine, but over a couple weeks back to cold cabin. One more point, after driving 15 mins and then letting FJ set for hour or so and I start it up I can smell coolant when walking up to FJ and a bit on the interior. I am pretty confused but if need be I will tackle heater core and head gasket. 220,000 plus miles but I love my truck. Thank you. Great site!
Yes, do your test for leaking heater core. Try this first: