Hi All, can anyone who has replaced the Purge flow valve on an LR3 tell me what the bolt size is? I can’t see anything and can’t tell if I am on the right part for sure. I have tried a few different sizes but no luck so far. Seems pretty small.

 

M6 x 1.0 x 20mm I'm guessing?

 

I'm pretty sure it's just a standard 8 mm head. I think I used a small ratchet and socket, but I can't remember for sure. You would likely benefit from a telescoping mirror and good flashlight to get a visual of it. From there it will be by feel to remove it.

 

Well, mine was a 7mm which is weird. Anyway. I got the bolt off and took a couple of pictures back there. Now to figure out how to disconnect the power and then figure out where the other end of the hose is connected. Hopefully once I disconnect the power, I will be able to see it.

 

For others….

i was able to get it off. Having the correct replacement part helped tremendously because I could overlay it and vishalize how it’s connected. The power clip was easier to get off than I expected and besides the bolt, nothing had a risk of falling down.

I started all of this because I keep having surging problems on start which would go away after about 10 minutes (and not come back unless the truck is turned off for a few hours) and I would randomly get the incorrect purge flow error. Unfortunately, the surging is still there and the jury is still out as to if the incorrect purge flow error is gone. But I guess I eliminated one thing…$200+ later.

 

Glad you got it done! If you think the surge could still be related to the evap system, you can remove the purge tube at the air intake and place a vacuum cap over the nipple. You will get a code, but you're isolating the evap system from impacting your engine performance. It's kind of dumb how expensive the purge valve assembly is!

 

yeah I for sure feel dumb for it not solving my problem! I honestly don’t know what it is. It is making a whistling noise during this warm up period and the surging. I know it’s not the water pump or the thermostat. (I have an odd suspicion that it is coolant related with the fan racing and then slowing down to surging).

 

Any codes? Reading live data during cold starts and during the surging may help narrow it down. The cooling fan normally runs high or full speed on startup and slows down after a short bit. My 06's aftermarket fan installed by the previous owner is way louder than my 07's stock fan.

I have not dealt with a surge, but monitoring Short Term Fuel Trim, Coolant Temp, might be a good start. A whistling noise could be a vacuum leak (or not) but it would definitely show on fuel trim if it is. Partially disconnecting the purge, PCV tube at idle while monitoring Fuel Trim gives you a good idea how sensitive it can be.

 

after a while I will get the error about the coolant temperature staying too low. I have also had the too high message. I have recently replaced the water pump, the thermostat, the top bleeder valve and the ect sensor. (ALL OEM) I have on my docket tonight to check the coolant level and bleed again tonight. And then I am going to try to monitor live values although I don’t know what I will be looking for exactly. I want to record a video too but it’s so hard to capture these engine noises well because everything is too loud. I have a stethoscope but my ears are too old to track down where that noise is coming from.