Hi all,

My long block came with all the seals/gaskets needed to build the engine up.

One of the seals is this o-ring like seal. Can anyone identify it? The water pump gasket is for perspective.



Thanks!

Steve

 

That's the thermostat neck o-ring/seal.

 

Hmmm...does this go on a 4.2L engine?

My thermostat housing had a flat gasket and that was it. When I removed the old thermostat, there was no other internal gasket.

Steve

 

You have an early build 1996 4.2. Anything built after 7/96 used this type of t-stat seal.Your 4.2 also uses a different type starter too,amongst other parts built pryor to the 7/96 date.If I were you,ide check into this.Also,gaskets fall under this too.

 

Well, this is interesting!

The truck is a 1998 F150. When I took the thermostat housing off, it had a gasket (paper type), but I do not remember seeing any rubber o-ring kind of gasket. I will double-check Haynes/Chiltons.

I fired up the truck last night for the first time (started right up), and I have a coolant leak at the thermostat housing, so maybe something is up!

I replaced the original Ford thermostat with a new one (non-Ford), and it came with the paper gasket also.

Steve

 

Yes,that is interesting.When I bought my t-stat from the dealer,parts guy asked for the build date on my door pillar.It was 10/96.I asked why,he said anything prior to 7/96 uses a paper gasket.

 

I was looking over my Chiltons and it shows on the engines larger than 4.2L a rubber O-ring that goes on the thermostat itself, but it looks like the thermostat housing would still need a traditional gasket.

I'm not sure that the 4.2L has a rubber O-ring in there. I don't remember seeing one when I disassembled the engine.

Steve

 

Well,my 97 uses the o-ring.And,I called my friend,who has a 99 F150,4.2V6,who recently changed his t-stat to a 180* one (I tried talking him out of it) and his had a o-ring.
BTW,the o-ring fits around the t-stat and fits into the groove in the t-stat neck.Notice the extra notch on the o-ring? That fits into the notch machined out in the neck,to keep the o-ring in place.

 

Hi Blue!

Yup, I looked at my O-ring, and noticed the inner diameter had a groove cut into it, and I noticed the tab. Also checked the Chilton/Haynes and could clearly see the O-ring (but did not realize the O-ring went around the thermostat flange - thanks for the tip.

But I'm pretty sure mine does not use the O-ring. I must have an older motor or an older thermostat housing, because my housing neck flange has no slot in it for the O-ring.

I cut myself out a new gasket last night and put her together with some RTV on either side, and didn't crank down on the bolts so tightly this time (I think I destroyed the first gasket by over-tightening). No leaks so far.

Drove the truck into work today for the first time with the new engine/tranny. Runs good! Woohoo!

Thanks for your help.

Steve