Lower intake gasket

[cdndrtbk]

Is it possible to be pulling air into the cooling sytem via a blown lower intake gasket?

 

[Wicked_Sludge]

unlikely. the cooling system is under pressure. it would be more likely to leak antifreeze out of a leaking manifold gasket and pull air in through the overflow tank (after its sucked dry) as the engine cools off.

 

[NeilC]

More than likely a blown head gasket, warped head or cracked cylinder head is causing the problem if your getting "air" into the cooling system. Is the cooling system pressuring up causing the coolant to over fill the reservior bottle? Also at times the coolant will get an odor almost like raw exhaust if you have a bad

 

[cdndrtbk]

My promblem arose after I changed the coolant temperature sensor. I burpped the cooling system and everything seemed fine. After driving the truck I noticed the temp guage fluctuating and a thumping from the cooling system. I went back to the shop and burpped the system again, still doing the same thing. I burpped the system 3 or 4 times with no affect, so I brought my truck to a local garage and had them remove and replace the coolant under vaccuum. Truck was fine for 2 days then the symptoms came back. So I wonder if somehow it is pulling air into the cooling system. Not overfilling the resivoir, not smelling exhaust in the coolant or coolant in the exhaust. The rad is always full when checked and resivoir is remaining at a constant height. I'm stumped.

 

[kkjb4x4.0]

Could a bad thermostat cause these symptoms?

 

[Wicked_Sludge]

theres a TSB on those exact symptoms for that exact truck.

its a flaw in the design of the cooling system. the best way to fix it is to have ford install the bypass kit, which modifies the flow of the system to prevent steam buildup (thats what your hearing).

 

[NeilC]

You may have an air lock in your system that will not bleed off without a little help. I have found that both rangers and explorers tend to air lock in the heater core after the coolant has been drained and it can be a real pain to bleed the air out. One trick I have found works well for me is I take an old radiator cap and cut the lower portion off ( the seal at the end of the spring). I fill the system and fill the coolant bottle to the full line then take the truck for a short drive with a couple of hard excellerations untill its warmed up. When I get back to the shop I top up the coolant bottle again and let the truck idle for a few minutes. If you see the coolant bottle bubbling while the truck is running then most likely you have a compression leak (cracked head, bad head gasket, cracked block etc) which is causing your problems. If you dont see any bubbles in the coolant bottle with the truck running then most likely it is just an air lock. Shut the truck off and let it cool down for an hour or so then replace the rad cap with the propper cap.

 

[cdndrtbk]

Thanks for the tip NielC, I have an old cap so I will try that method. Wicked Sludge I have read the TSB all the symptoms are correct as you say. It just seems odd to me that this problem started right after I replaced the sensor. The truck is 10 years old why would it just start happening now? In my mind it has to be air trapped, or a real coincidence.

 

[cdndrtbk]

Nielc do you mean to remove just the rubber seal or the whole piece(rubber seal and brass backing plate? spring too)

 

[NeilC]

I removed the entire spring and backing plate from the cap leaving only the upper gasket that seals at the top of the rad filler spout. I think it would work by just removing the rubber seal as well.

 

[dorman68]

More than likely a blown head gasket, warped head or cracked cylinder head is causing the problem if your getting "air" into the cooling system. Is the cooling system pressuring up causing the coolant to over fill the reservior bottle? Also at times the coolant will get an odor almost like raw exhaust if you have a bad

I agree