Dave2017

I am relatively sure I need to change the head gasket on my 94 f150 4.9L.

Did a coolant change with the flush from Prestone. Drove it for a few days before clean water rinse and new coolant.

Shortly there after I noticed air intake on valve cover blowing oil in small amounts into air cleaner housing. White smoke was also coming out PVC or valve cover intake.

Is this indicative of blown head gasket? How hard is it to replace?

I am mechanical and very good with tools and confident. Do most all preventative maintenance including brakes and rotors, etc... Used to rebuild motorcycles...

raski

I would suspect excessive blowby due to a ring problem.I never heard of a head gasket causing your symptom.. Head gasket issues are rare on a 4.9. Pressure testing the cooling system and compression/ leakdown checks are in order. Also make sure you have sufficient vacuum at the pcv and the breather/filter is clear.

Dave2017

Thank you Raski! I appreciate the response...


I knew the pressure and compression tests would come up... Just don't have the gear or access to them...


New PVC and have vacuum at intake manifold for PVC... But, I will double check again...


I may have had the blow by issue and it slowly got worse. But, how do we explain the coolant in the oil??? I was told a bad gasket could cause my issue with the coolant & oil especially after using a strong prolonged flush... Also replaced hoses and tstat... tstat is opening and closing. Have pressure in cooling system...


I grant you, I could have two separate issues... But, only testing will confirm... I think I may be able to rent test equipment...


Many Thanks Again!
Dave...

raski

Sorry, I missed the coolant in oil in your title. I was wondering if you had these problems prior to flushing? You could even have a cracked head. Putting cold water into the hot engine during flushing might do that.

techrep

iTrader: (1)

Or a intake manifold leak

Dave2017

Hi Guys! thank you both for responding... Sincerely appreciate it...


I think I may have had the blow by issue in a mild form. I also think I am getting some coolant into the cylinder that turns into steam which is blowing out more oil than normal into the air cleaner housing. The coolant in the oil (I think) is from a failed head gasket from the prolonged flush. I understand older gaskets do break down over time. F150 has 170+ miles on it. Head gasket most obvious culprit to me...


I would never put cold water into a hot engine. No chance of cracked head. Intake manifold could have a leak but I doubt it. But, will check anyway.


I am losing coolant and oil in very, very small amounts. Too small amount to measure... I did check the white smoke, it is not oil, it is steam... I think the steam is pushing more oil out the valve cover into the air cleaner...


Hence, why I think small hole in head gasket allowing coolant into cylinder but not enough to keep it from firing


I will double check manifold leak and ensure good vacuum on PVC.


BTW - Is it hard to change the head gasket? How long would it take and what are the gotch ya's to look out for...


Many Thanks,
Dave...