EGT Probe Removal Help

[455]

I have Racepak EGT probes in headers, removal of the probes can be very difficult at times (several day process). Is their a high temp anti sieze or other product that can be used to help keep the two tapered surfaces that seal the probe from sticking together?

My process for removal is to lossen the nut, and soak the probe in the header with liquid wrench each day for two days and more. I then see which one can be rotated and removed after two days. The last ones can take over a week.

I see two issues in their removal1). the probe itself gets a build up of gunk on it, making it larger then the header hole opening ( adding the liquid wrench softens this and allows removal); 2). The two tapered surfaces that seal the EGT probe to the header stick together, preventing removal of the probe. Worst case for removal has been to heat the probe and rotate with significant force (damaging probe in process).

My thoughts are to ream out the header probe holes a little for more clearance for the gunk on the probe, not damaging the sealing ( tapered) surfaces, along with a lubricant that would prevent tapered surfaces from sticking, if such exists.

Recommendations on what to use for preventing tapered surfaces from sticking together. Any other suggestions.

Thanks,
Les Otte
323 D/SA

[FED 387]

Have you tried anti sieze on the threads??? also heating the area around the probe with a propane torch just a little to help let the metal expand some times works--- if the use a NPT thread you might use a NP straight tap instead of the taper tap just put the probes in and SNUG them in NOT OVERLY tighten when installing---worse case scenario remove and re-install after every weekend to keep them free--you will have to use a socket or line wrench to totally engage the flats on the nut otherwise your gonna round it off then you will really have problems--- what does Racepak say????

[FED 387]

Have you tried anti sieze on the threads??? also heating the area around the probe with a propane torch just a little to help let the metal expand some times works--- if the use a NPT thread you might use a NP straight tap instead of the taper tap just put the probes in and SNUG them in NOT OVERLY tighten when installing---worse case scenario remove and re-install after every weekend to keep them free--you will have to use a socket or line wrench to totally engage the flats on the nut otherwise your gonna round it off then you will really have problems--- what does Racepak say????

[Tom Goldman]

Permatex 77124 Nickle antiseize works the best for hi exhaust temps and dissimilar metals. ....I coat the probe sheath where it goes thru the brass fitting.
We've used it for years on O2 sensors at the shop . ...they always come back out ,even years later.

[chris ok]

My trick.
Gettingout O2 sensors has always been a problem in toyotas since the steel header exhaust manifolds and it was found brake fluid is the best lubricant to get them out.
Right from toyota engineering. Where we've gone to steel header exhaust manifolds it is often impossible to remove the sensors as opposed to cast iron manifolds. Works all the time.

[BlueOval Ralph]

GM has a special anti-seize for O2 sensors that does not screw up the sensors kinda pricey but so are O2 sensors

[chris ok]

We've tried everything. I will crack an O2 and then it appears to want to bind and cross thread. I put brake fluid on it. Wait a few minutes and they come out. Put the brake fluid in an oil can squirter and spray on. And its cheap. Always works. A secret Toyota does not like to let out, but for the racers, anything.

[MOTORSPORTS Innovations]

A bit Anti-Sieze on the shaft and in the cap will do the trick.


I'll have to try the brake fluid trick on my next tough to remove fitting - thanks Chris. Does it work on bolts too?

[455]

Thanks for all your help, your suggestions should make removal much easier in the future!!!!

Racepak said their standard procedure after they install the EGT Probe holders in headers is to drill out the hole with a 17/64 drill bit. The probe and holder hole diameter is about .255" or .254"and the drill bit is about.264. Racepak says the two tapered surfaces( the one on the probe and the one machined into header holder) are what keep the probe in-place. They use this procedure on Top Fuel dragsters headers, so it should work on a "stocker".

The additional clearance in the header holder, along w/ all your help for for the tapered surfaces with two different metals will make removal much easier in the future.

Thanks again for all your help.
Les Otte