Coolent System Thermostat

[volamoose]

Good morning, I'm some 10 years into this Bongo malarkey and still seking solutions. I strongly suspect my thermostat is knackered and have read of it's removal, but can't find, with a few searches attempted, what if any are the major downsides to this. My aim is to remove the springs & stuff so I can still fit the body of the thermostat, I would be grateful if any of the Bongo oracles could point out the glaring but as yet unspotted (by me ) error in this plan? thanks!

[haydn callow]

Just put a new one in !!!! Simples
Not a good idea to remove the workings......it controls the engine temp and removing it will mean it never gets to a good constant working temp.

If you are removing it because it overheats.....again not a good idea.....you need to fix the cause.

[mikeonb4c]

Ditto with Haydn.

4wd trickier to change than 2wd. With the former, official advice I think is drop the driveshaft but I''ve read some have managed it without doing that, using (i think) knuckle jointed socket set.

[rita]

Why do you want to doctor the old thermostat, does the vehicle have an overheating problem.??

[volamoose]

it has overheated, but I believe the thermostat not opening was the cause, as the bottom pipe on the radiator remained cold, why remove it, because they stick shut on a regular basis. I may be wrong on both counts which is why I've posted the question

[volamoose]

to clarify, I was losing small amounts of coolant....no sweat checked round..small drip from a hose, sorted that, refill bleed, bleed and bleed a bit more. test drive, overheat bleed a bit more...read up, suspect water pump ( due to a few other symptoms which would be too long winded)..change pump...damn...glaring error, cold bottom hoses...read up...suspect thermostat....so here we are. I've just ordered a replacement thermostat, I suppose I just wondered what purpose it served, I thought it just brought the engine up to temp a little sooner, but once open that was that....so why not just dispense with the gubbins leaving the body in place due to the seal.....every day is a school day!

[haydn callow]

I repeat my advice above!! They do not stick shut on a regular basis.......put a new one in...gen Mazda......it will probably overheat again and you must find the cause.....head could be cracked after overheating...
Did the coolant level drop....have you a coolant alarm fitted?

[volamoose]

yes the level dropped a few times, but never overheated till I drained the system to repair the dripping hose. I realise the head maybe cracked, but with a cracked head I still would have thought that the bottom hoses on the radiator would have got hot as I didn't think the head being cracked would stop the coolant circulation?...No no coolant alarm, but a new head some four years ago

[volamoose]

oh and after your liberal use of exclamation marks,you needn't fret I have already ordered a replacement thermostat!!

[haydn callow]

Did you bleed it according to the YouTube videos?

[haydn callow]

What !! Marks

[volamoose]

I have since seeing the videos yesterday, previous to that I was bleeding it with a method posted previously on here, bleeding through and maintaining level in header, which incidentally has always worked for me in the past.

[volamoose]

Right, I'm at the end of my tether.....thermostat changed...bottom of the radiator is still cold....I have read back and whilst I wouldn't expect the bottom hoses to be as warm I would expect a little more even temperature in the rad.
So am I facing the almost inevitable conclusion that head #2 has gone, in which case I am afraid she's down the road!!?
All Ideas gratefully considered.

[francophile1947]

You have to rev the engine, with the vehicle stationery, for a long time to get the bottom hose hot, which is why bleeding takes so long. During normal driving I don't remember my bottom hose ever getting hot - it really needs long hills or a good blast along a motorway - it's not like a normal car.

[Titan1995]

Easiest way I found is to remove the thermostat housing from the block.

This will allow you to fit the thermostat a lot easier.

The housing to block gasket is readily available from any Ford dealer.

Presuming that you are talking about a 2.5 diesel engine of course.