What is that screw for?

[Shaun]

Working on my FJ 1990 pull the oil drain plug and notice there is a screw in it from the outside. I looked at the plug and the screw hole does not go all the way through, it seems to end in a blind hole / dead air space and do nothing in particular. I thought I read something about this before so I tried searching the site and got no where really, so no joy there to it's purpose so I'll try the those who know things FJ. Not really important just curious on thoughts to what and why.

Shaun

[SlowOldGuy]

The dealer's shop will attach a temperature probe in the drain screw when they are adjusting carb mixtures using theie Exhaust Gas Analyzer.  It monitors the oil/engine temperature.  The EGA probes screw into the exhaust headers, see the bolts in each header tube just before the collector.

DavidR.

[Marsh White]

Thanks David!  I had always been curious myself as to the purpose of that screw on the drain plug AND the header bolts - you fixed us up in one fell swoop!   

[Kopfjaeger]

i ll say!!! i read that they were drain plugs? on the headers.....makes sense now. speaking of all things oil and temperature, has any one fitted a temp gauge where their oil cap goes?

[Harvy]

i ll say!!! i read that they were drain plugs? on the headers.....makes sense now. speaking of all things oil and temperature, has any one fitted a temp gauge where their oil cap goes?

Neil, I looked into getting one of those gauges that goes into the oil filler plug hole, BUT....... its not a line of sight path down to the oil level...... the clutch cage is in the way, so I don't see how you could get accurate temps with them.
I did the temp probe in the oil galley plug method....... at least that is always in oil so should be accurate.

Harvy

[Kopfjaeger]

cheers harvey. i just though they looked cool!!!! i remeber hearing someone saying " you know why they dont put numbers on oil temp gauges in some cars? cos the owners would sh*t themselves!!!"

[turbocamino]

  Or maybe...if you have a header that wont allow drain plug access.... you could do what i did last week and remove the screw install a 5mm bolt and weld it in ...now a long allen wrench can reach up between the pipes and R&R the plug.  I was concerned at first that i wouldnt get it tight enough but after a few tests..all seems well.   

[Travis398]

  Or maybe...if you have a header that wont allow drain plug access.... you could do what i did last week and remove the screw install a 5mm bolt and weld it in ...now a long allen wrench can reach up between the pipes and R&R the plug.  I was concerned at first that i wouldnt get it tight enough but after a few tests..all seems well.   

that's a pretty cool idea