Thermostat replacement time?

[HoosierJeeper]

This will sound bad but somehow I just realized the only cooling part on my KJ that's OE is the tstat. I have 165k on it. I'm heading to a Jeep show about 4 hours away in a month and don't want any issues. I don't have any symptoms....it heats up as fast as it always has and has good heat. I've read lots of bad stuff about newer replacement Tstats (Mopar and others) not working at all and overheating.

Should I let a sleeping dog lie?

 

[rjkj2005]

With all the stores of bolts braking off while trying to change the t stat. I'd at least wait till after you trip. Hate for you to miss it trying to fix something that's not broke.

Sent from my XT1585 using Tapatalk

 

[tjkj2002]

Replace it when it fails since you have so many miles already,the chance of a broken bolt trying to replace it increases drastically when at high miles with no replacement history beforehand.

 

[HoosierJeeper]

Yeah, that's another thing I was worried about. Is there a way to prevent that? How hard is that to fix?

 

[tjkj2002]

Yeah, that's another thing I was worried about. Is there a way to prevent that? How hard is that to fix?

The top hole you can't do much but the bottom hole goes all the way through the front cover so you can soak that bolt with what ever you like from behind.

I have found having the engine at full operating temp works for those "known to break or stick" bolts,expands that aluminum enough to get the bolt out without breaking.Just got to be very careful of hot coolant so try at your own risk.

 

[HoosierJeeper]

Could at least get them loosened with it at full temp and then let it cool down to finish the job.

What happens if they break? Is it a major hassle?

 

[tjkj2002]

Could at least get them loosened with it at full temp and then let it cool down to finish the job.

What happens if they break? Is it a major hassle?

Yeah you can break them loose then allow to cool,I don't get that luxury at work.

The top bolt is a pain but the bottom is easy.

Top = Hope you can drill the bolt out without damaging the front cover,retap.

Bottom = drill through and use a bolt and nut,or you can retap.


I have been lucky and only have run into the broken bolt for the t=stat housing about 3-4 times on the 3.7/4.7's.All with very high mileage also,like 200k+ miles.

 

[HoosierJeeper]

Trying to think if I'm better off trying it myself when the time comes or taking it in, I don't trust myself to drill/retap and not damage the timing chain cover. Is doing it with the engine hot likely to work? For a good shop, how many hours labor does the worst case scenario involve?

Thanks for all the help.

 

[tjkj2002]

Trying to think if I'm better off trying it myself when the time comes or taking it in, I don't trust myself to drill/retap and not damage the timing chain cover. Is doing it with the engine hot likely to work? For a good shop, how many hours labor does the worst case scenario involve?

Thanks for all the help.

A common issue for the 3.7/4.7 is a seized belt tensioner bolt,trying to remove with a cold engine = no-go,but warm up engine and it comes right out.Same applies to those 2 t-stat housing bolts.

I also never attempt to loosen those t-stat housing bolts on 3.7/4.7's anymore with power tools,hand tools only to judge if the bolt is going to break or not.

 

[LibertyTC]

I would leave it alone.
Sounds to me like you have a good working OEM thermostat.
As long as the Jeep is keeping cool & in the mid range on temp gauge, I say you are good to go.
Have you replaced the water pump yet?

 

[HoosierJeeper]

Yep, water pump and radiator at 108k. Hoses last year, probably have 10-15k on them. Coolant temp sensor about then too.

Don't know how it slipped my mind...but that's what having 4 needy vehicles does. Always a fire to put out lol.

 

[HoosierJeeper]

A common issue for the 3.7/4.7 is a seized belt tensioner bolt,trying to remove with a cold engine = no-go,but warm up engine and it comes right out.Same applies to those 2 t-stat housing bolts.

I also never attempt to loosen those t-stat housing bolts on 3.7/4.7's anymore with power tools,hand tools only to judge if the bolt is going to break or not.

Missed this one when I replied to TC!

I followed that tip when I did my tensioner a few months ago (wonder who told me that:gr_grin: - thanks), came right out....maybe I will give it a go on my own.

Thanks everyone.