What a winter....the heater in my 98 4.6L F150 (130k miles, original owner) was no longer pushing hot air. Assuming a clogged core, I removed the heater hoses under the hood and blew them out with 20 PSI air - lots of rusty crap came out. After that, all seemed good, with fresh heat now being produced.

To complete the job, I drained the old antifreeze from the petcock and flushed out as much as I could without disassembling the lower rad hose or t-stat housing. I then refilled with water and some Prestone Cooling System Cleaner in preparation for a full flush with a new t-stat.

After driving around town for a few days, I decided it was time to do a full flush. The heater had been good and the temp gauge was in range where it always has been. I thought I check the oil level, and..oh, the horror!

A light brown mocha-colored oil compound was on the end of the dipstick. The oil fill cap was full of the creamy white goo discussed on so many other threads on this board as a result of short drives in low temps. Assuming the worst, I drained the oil - all mocha-colored - and removed the t-stat housing and lower rad hose to do a more complete flush of the cooling system.

I let the truck sit for a couple of weeks to let all the bad oil drain out, then refilled the cooling system, installed a new t-stat, removed and cleaned both temp senders, and put six quarts of 10-W40 in the crankcase with some Seafoam.

Prior to the latest adventure, I threw a P0305 code, so I replaced the Number 5 plug. The engine now runs rough and doesn't heat. In reading the threads, I'm contemplating a new water pump, intake manifold gaskets, PCV valve, and removing the block plugs to get a more thorough flush. The next step would be head gaskets. Either that, or just running the engine until it seizes up and swapping in a remanufactured long block, but that ain't cheap.

Questions:
Based on the syptoms above, is the motor terminal?

If not, am I going down the right path to fix it?

Thanks!

Nick

 

hey man sounds like head gasket to me, if you are that mechanically inclined to do all that other stuff i would just go ahead an replace the head gaskets at the same time beats the hell outa doing all that stuff and still having the problem, i would also say you are better off doin this as your motor has a lot of life left in her with only 130k

 

Sounds like a head gasket or intake manifold gasket, also sounds like you are going to need to put in a new heater core soon with all the rust that came out of it.