1FZFE Thermostat gasket replacement (1 Viewer)

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Hi there fellas,

Simple question. I'm about to install a t-stat on a LX450 without it and after checking the FSM, as you can see below, I understand that the t-stat goes first, than the gasket and last the housing.

Screen Shot 2020-08-19 at 8.40.03 AM.png


However, after checking the new oem gasket it looks like there is a 360˚ groove on the inner side, image also below. Now i'm questioning if the t-stat edge should attach to the inner groove of the o-ring so the t-stat edge is covered by the gasket.

Screen Shot 2020-08-19 at 8.48.38 AM.png


I have tried placing the parts together as the FSM states but without closing the housing just to see how things would sit and it is hard to keep that loose gasket in place before closing the housing. Nothing that some tiny bead of grease couldn't help but still, i'm intrigued by it.

Does anybody know if the gasket should sit atop the t-stat as the FSM diagram shows or does it need to attach and cover the t-stat edge?

Any help is greatly appreciated. Thanks
 
Change the bypass o-rings while you’re there.

Hi Joe! Thanks for the suggestion.

Yea, I replaced the whole bypass assembly last month (bypass pipe, inner pipe and o-rings) as the whole thing was leaking and not looking good. By the way, just a suggestion...that could be another kit that you could sell on your website as it is directly related to the t-stat kit that you already sell. A water bypass kit with the pipes and o-rings. I'm sure it would make some 80series owners life easier.

I finished the t-stat job this morning and went for a drive, the rig is running smooth with a new cooling system and around 2˚F cooler. Thanks @flintknapper for the heads up on the correct gasket placement!

And again thanks Joe/Wit's End! I got most parts for the cooling system there and the service is spot on! Those kits really make it easy to maintain these trucks. 🥃🥃
 
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Very good reference! Thanks for sharing.

I replaced exactly those parts last month, it took me sometime to find all the part# but internet helped as always.

Now, everything is sealed and ready to go. phh is next, can't wait 🥵

Yeah, PHH is a fun one. Putting toothpaste back in the tube is easier.

But it's 'rite of passage' around here, so you earn street 'cred' if you do it.
 
I did the front axle service well before attempting the PHH.

PHH is way simpler.
 
Does part# 90301-29006 By-Pass Pipe o-rings come 3 each from the dealer?
 
Does part# 90301-29006 By-Pass Pipe o-rings come 3 each from the dealer?

No, sold individually. Requires (3) IF you pull the connecting pipe.
 
I did the front axle service well before attempting the PHH.

PHH is way simpler.

That is encouraging. These 2 jobs are the next ones on my list. Have to find the Koyo bearings for the front axle though, it looks like there has been a shortage on those these days.
 
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That is encouraging. These 2 jobs are the next on my list. Have to find the Koyo bearings for the front axle though, it looks like there has been a shortage on those these days.


Try @Cruiseroutfitters
 
Timken bearings seem to be easier to find, and are high quality as well.
 

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