Bongo Fury

I recently changed/flushed the coolant (hadn't been done since Nov 06) and replaced a slightly swollen hose (from engine to steel pipe, slightly swollen at engine end of hose) and all has been well. However, after bleeding the system, and for the last few hundred miles I have been regularly (ok, obsessively) checking that I got the hoses tight enough. I didn't get the clamps on the new silicone one quite tight enough first go. While bleeding and feeling up hoses I have become aware that the bottom hose is perhaps not getting hot as quickly as it used to, and is just getting warm rather than hot. I think it would probably be a good plan to change the thermostat. My question (after this long preamble) is whether to replace the thermostat I simply undo the two downward-facing bolts on the thermostat housing (which look hard, but not impossible to get at). Will the housing come apart after doing this? Or do I need to undo the steel pipe as well (I didn't notice how or whether the steel pipe is attached to the frame).

why change it if your system is working? all you are going to do is change something that is working for something else that is working?

If you have doubts about the thermostat, it's easy enough to change, on my 2wd, I did it from underneath (the tray was off as I was doing the hoses anyway), undo the bolt holding the dipstick in place & push it to one side & then it was easy enough to do. As you say nfn, just the two bolts & you've got it. check the old & new stats in a pan of water brought to the boil, if you've got a thermometer capable of reading up to 100 degrees c you can check when thet start to open & close. I didn't have, but the new one opened way sooner than the old one.
It may be worth using a rad flush to clear out the cooling system, I did it with the stat out (easier to bleed & flush thoroughly), just put the rubber seal back in off the old one. I used the holts 2 part system, took a good few hours to do, have to let it cool between emptying & flushing (drop out of the lowest hoses & backflush though wherever you can with a hose). Just don't forget to put the stat back in
At the very least try & back flush the rad with a hosepipe.
Obviously you're ok with the bleeding procedure if you've done a hose already, but after flushing thoroughly, it'll be burping & farting all over the place

If i have read and remembered this correct, on this forum before, the bottom hose does not get as hot as the top hose. so it is probably OK and the thermostat is working, worth changing the thermostat next time you change the coolant for any reason.

Thanks Kirsty -- it's good to know that it's best to tackle the bolts from underneath. I did backflush the rad with the garden hose: I took the hose I was replacing and duct-taped it to the end of the garden hose. I then stuck the other end on the bottom of the radiator and turned on the hose. Water came out the top of the rad pretty quickly. I was amazed that the duct tape held with very little leakage. I didn't see much crud come out -- some little flakes like you get on the bottom of a kettle. I don't know whether I can assume from this that the rad is okay.

daveblueozzie wrote:If i have read and remembered this correct, on this forum before, the bottom hose does not get as hot as the top hose. so it is probably OK and the thermostat is working, worth changing the thermostat next time you change the coolant for any reason.

I agree and the workshop manual uses the word 'warm' not the word 'hot' when referring to bottom hose in the advice on bleeding, which I think is probably significant. I just posted this on LondonRons thread wrt the thermostat, in case it adds anything:

mikeonb4c wrote:Easier to change thermostat on a 2WD as there is no propshaft in the way. Some have changed 4WD thermostat with propshaft in place (from underneath maybe? v. old advice but have a search and maybe it will turn up) but workshop manual says disconnect it. I've changed my 2WD one without problems (need to make sure you put new one in the right way up - I nearly didn't even though I think there is a little locator nib to help you get it right - so note whch way up the old one is when you take it out). I didn't need any special parts.

Obviously, you are going to have to make sure you bleed it properly. I did print the advice from the workshop manual on here recently. Have a search using the word 'manual' and the thread with that advice should be shortlisted (about 1 weeek ago I typed it I think)

Good luck and congrats on the new job.

Given the responses, I may wait and see if my Mason alarm gets peepy in warmer weather and with the longer journeys that it will be doing in the summer before I go ahead and change the stat.

You can get the stat housing from a 4wd without removing the propshaft - you just need a universal joint between the extension of your socket set and the socket - just make sure that you are not directly underneath the housing when you remove it

I will find out if you can get the thing back on when my new stat and radiator turn up

and you dont have to be under the van to do it, i changed ours on a 4wd from above, even with big hands it wasnt too knuckle bashing.

dreamwarrioruk wrote:and you dont have to be under the van to do it, i changed ours on a 4wd from above, even with big hands it wasnt too knuckle bashing.

HOW did you manage that I looked at changing it from the top - and then banished such thoughts from my mind - you have my respect

you cant see what your doing but got to feel your way around, a universal joint on the socket set is needed and the only hard nut is getting to the one at the back,also a pain to get the gasket to stay in imo