So I think I need to replace the thermostat on my 2006 LR3V8. The housing is fine and no leaks but amber check engine light with code that leads me to believe thermostat. So can I replace just the thermostat itself or must I replace whole housing like repair shop said. I pretty handy mechanically so hoping to do myself if not to big a job.

Thanks

 

You can replace just the thermostat and I think it is significantly easier than replacing the entire housing. I believe getting the lower part of the housing out is a fair amount of work, but just taking the top off and replacing the thermostat is certainly the way to go if that's all you need.

Gasket - P/N 4362513
Thermostat - P/N LR005765

 

The thermostat if OEM should come with the gasket. It is a fairly straightforward job, but take the thermostat housing piece inside to a bench and remove the thermostat there. You will find that all the stories about the tiny thimble are true... I had to do a midnight run to the dealer because I lost one... twice.

If the housing assembly is cracked at all, expect to replace it at some point (soon hopefully). If you are lucky it will be in decent shape.

Oh and remember to burp the coolant loop

 

...might wanna replace that (plastic) bleeder T in your coolant loop with a brass one. You're likely to break it while bleeding it, anyway.

 

You can bleed it without touching that T at all... But I did have to open it to get coolant out of the thermostat housing. Brass isn't really necessary if you have a spare, or 5!

Just don't touch it while bleeding anyway, more messy!

 

It's such a weak link I'd really suggest replacing it knowing it'll last the lift of the vehicle / frame etc. Mine bled on a gravel driveway and I was lucky enough to SMELL it before there was any temp fluctuation on the gauge at all.

I hate stuff like that where there's zero warning, that's not how I work with my "preventative maintenance attitude" - I like to fix stuff before it breaks and it's worked great for me in the past. This type of thing sucks and I want nothing to do with it - especially if the fix requires either a more expensive OE part that'll break, or a cheaper brass part that's impossible to break.

Also for the record when mine blew, it took A REALLY REALLY LONG TIME to bleed the air out of the top bleeder. OE procedure is insane and requires multiple cold-hot cycles, certain RPM holds, etc. The brass fitting is threaded and allowed me to fit a tube to a funnel and force fill the system with coolant and bleed it out faster and more thoroughly.

 

I agree, but I never actually got around to getting a brass one... yet.

as for bleeding/burping, I referenced this in another thread but a dealer tech actually came out to my service advisors desk and explained how he does it.

pretty much boils down to close everything as normal except for coolant expansion tank cap. Start the engine and run @ 3000 (i think) rpm and watch temps. Keep heater controls at max heat. Around 197F the t-stat opens and dumps coolant into the full loop. Once it opens, shut off engine, let cool a bit, and top up coolant to line. Repeat two times, put the cap back on after everything is done.

Been months now and I have perfect coolant temps, no bubbles.

 

I forgot to ask the OP - are you getting the "failure to reach operating temp" or whatever error code? If so you should PROBABLY be seeing lowered readings on your temp gauge (though not always). Just curious what is leading you to replace the tstat without a leak.