2008 tundra limited potential problem

I have a 2008 tundra limited double cab 5.7 and I am slowly losing coolant but can’t see where it’s going. No condensation under oil cap and no visible leaks underneath. I have 148,000 miles. Changed my rad about a year ago because it was leaking. I’ve also noticed my gas mileage has been horrible. Use to get 12 mpg now I’m getting 9-10. When I changed my spark plugs at 100k there was oil in the spark plug holes of 2 of the 8 (I’m aware that I probably need to replace the valve cover gasket)

Anyone else ever have a similar issue? I’m fearing that I need to replace the head gasket.

much appreciated!
Mark

 

Take your engine cover off. Take a flashlight and shine it between the risers of the intake and check to see if you have coolant in that valley between your cylinders.

 

Pull the splash pan and look up at the bottom of the water pump. It wouldn't surprise me if you find pink crusties around the weep hole at that age and mileage. I replaced mine a few years ago for that same reason.

 

I second this. The pump will weep just enough to evaporate without a visible leak due to the seal design. I’ve not had the issue myself but have read several reports of it. I asked the lead tech at dealership about it once and he confirmed they see it often.

 

Thanks guys!