I have a 2000 F150 with the 5.4 that has developed a really bad miss and consumes coolant at a pretty good rate. I pulled the codes and it's missing on cylinder 1. There is coolant in the cylinder.

Also when you first start it up, the temp gauge slowly goes up to the red line or close to it before it falls back to normal. You don't get heat until it starts to fall back.

It also has coolant in the oil and the milky froth until the oil filler cap.

I have thought it was head gasket related. I used Bar's Leaks and it stopped the problem for a while. Now it's back.

So I called my local dealer for a price quote. He said around 2500 bucks for a passinger side head gasket. But he also said that he didn't think it was a head gasket. He thought it might be intake gaskets. I found one other thread in the 5.4 forum about a guy with a similar problem and it being an intake gasket. Maybe it's a problem with the plastic intake manifold. (WTF is with plastic anyway?)

What do you all think?

Mike

 

I figure that other than hard engine part failure such as head or block cracks, that the only way that water could get into the #1 cylinder is through the intake manifold gasket or the head gasket.

So if I change the intake manifold gasket and that's not it, then it would have to be the head gasket if it's not a failed hard part.

Also, the missing is much worse after warm up than when it's cold. It's especially worse after the temp gauge goes up and then falls. If it was a head gasket, I'd think that it would be missing about the same all the time.

Mike

 

Anyone, anyone, Bueller? Fry, Fry?

Mike

 

The temp gauge actually reads head temp, not coolant temp.
It is possibly an intake gasket, to tell, remove the intake and see if there is coolant in the intake port, if not, it is either the head gasket or a cracked head.
The coolant passage is not plastic, it is aluminum, the air intake part of it is plastic.

 

Thanks for the reply. I'm tearing into the engine this friday to see if it's an intake manifold gasket.

I'm thinking that it's probably this because of what the dealer said and from the thread I found here with almost identical symptoms. The poster said that the original gasket only had one seal between the coolant passage and the air passage. The newer gasket has a seal for each one.

Also wouldn't a head gasket miss about the same all the time? It doesn't miss very bad until it's warmed up and you can't feel a miss very much above idle speed. The only time you can feel the miss when cruising is at low RPM in OD. Don't head gaskets get worse over time as well.

You've probably noticed that I'm praying that it's the intake gasket and not the head gasket.

Mike

 

Is there any compression in the cooling system? Usually a head gasket will allow compression into the cooling system and cause bubbles and alot of pressure.

 

IDK if there is any more compression than normal.

As far as bubbles, it's been puking coolant when I fill it. It does that when the temp is at it's max, and then it falls back to normal.

The reason I think that it's intake manifold vs head gasket is how it runs when it's first started. It's almost smooth. It only misses every now and then. After the temp rise and fall (which I assume is it switching from closed to open loop), it misses like crazy.

I'd think that a head gasket would miss right from start up. I'm thinking that the system is low on coolant and only after it goes into open loop is there enough coolant to reach the intake gasket. It's only after the temp rise and fall that I get heat as well. I haven't filled it up lately and it now only has heat when the RPMs are up.

Mike

 

A headgasket may not show till it heats up also. Hear is a little trick we learned yrs ago ,If you have the tools
Compression tester and a cooling system tester.
Get the engine warm ,then get the cylinder that you think is having the problem at top dead center both valves closed ,Pull sparkplug and install commpression guage the put cooling sytem pressure tester on and pump up and watch the compression guage .
If the it starts to rise 9 times out of 10 its a headgasket,unless its leaking between cylinders .Don't over pressure the system !

My best guess is the head gasket.

Rich

 

Well I rented the coolant pressure tester and it didn't have the screw on adapter.

So I'm just going to tear into the engine tonight and look at the intake manifold gaskets. If they are ok, then it's most likely the head gaskets right?

Mike

 

I'm afraid so

 

Thanks for the help guys. I didn't get a chance to tear into the engine this weekend as I ripped my left big toenail off and tore up the toe pretty bad. So I didn't really feel like working on the truck.

I'm still holding out hope that it's the intake gasket as it runs pretty much smooth as glass all day long at anything above idle. I'd think that a head gasket would miss more.

But we'll see when I get into it.

Mike