A couple questions....

[turbododgewagon]

I have 2 things I need cleared up if anyone can help me...

I need to know what size and thread plug goes in place of the top plug and the coolant line out the side of the thermostat housing. Anyone know?

And does anyone know what these are? Are these the accelerometers for the SRS?

[black86glhs]

If I remember correctly it is a 5/8" x 18 plug. Those look like the air bag sensors, but I'm not 100%.

[turbovanman²]

The top most plug is 3/8 pipe thread as is the coolant pipe exit and the coolant temp sensor.

Those look like something to do with the air bag system.

[black86glhs]

I wondered if it was pipe thread. I checked the thread count and it was #18 on my thread guage. Temp sensor measured 5/8" in diameter. Thanks for the correction Simon.

[turbovanman²]

I wondered if it was pipe thread. I checked the thread count and it was #18 on my thread guage. Temp sensor measured 5/8" in diameter. Thanks for the correction Simon.

I think your right on the 18 pitch but they just call it pipe thread. It does come in a fine thread too,

[Clay]

tapered pipe thread is tapered pipe thread.

No course or fine for tapered pipe. it is what it is.

3/8" NPT is always 3/8" x 18 thread. Always. Etc.

[turbovanman²]

tapered pipe thread is tapered pipe thread.

No course or fine for tapered pipe. it is what it is.

3/8" NPT is always 3/8" x 18 thread. Always. Etc.

Your wrong on that, the threads in the head are straight tapped, so yes, its just 3/8 X18, and yes, you can get fine also. The fittings and sensors are tapered,

[Clay]

Your wrong on that, the threads in the head are straight tapped, so yes, its just 3/8 X18, and yes, you can get fine also. The fittings and sensors are tapered,

I may be reading your post wrong...... but

You're saying that TAPERED PIPE threads (ie NPT) are available in course and fine thread?

[turbovanman²]

I may be reading your post wrong...... but

You're saying that TAPERED PIPE threads (ie NPT) are available in course and fine thread?

Yes, when I ordered the tap, they wanted to know fine or course thread.

[Clay]

Hmmm maybe a mistake on their part, but as far as NPT/ US tapered pipe thread goes, one size is it. in fact there are only like 5 different pitches for threaded pipe in the US: 27, 18, 14, 11-1/2, and 8.

[black86glhs]

At least I still remembered pipe thread was tapered...lol!

[Tonatom]

There is tho NPTF which is fuel pipe threads which would be considered by a lot of people "fine".

[Clay]

NPTF are just dry seal NPT threads, ie they require no sealant to seal, but they are the same size and pitch more or less. The major and minor diameters of the threads are a bit different so you have no gap when they are screwed together, so they require no sealant, ie dry seal.