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Coolant leak from Thermostat housing

Posted: 11 Oct 2014, 11:03
by madoc
T25 1.9DG

Looks like I have a coolant leak just over the rear left exhaust manifold, i.e. coming from somewhere within that thermostat housing assembly.
I don't think it's the pipes but it's tough to tell.

I can see there is an O ring on the housing but is there a gasket between the housing and the head or indeed anywhere else in there ?

If I have to dismantle it and lose coolant, then I'd rather do it the once ....

Re: Coolant leak from Thermostat housing

Posted: 11 Oct 2014, 11:06
by madoc
scrap that .. looks like one of these does the job:

http://www.brickwerks.co.uk/index.php/t ... t-2wd.html" onclick="window.open(this.href);return false;

Is it worth a new housing ?
How bad do they get ?
Anything else needed ...

Re: Coolant leak from Thermostat housing

Posted: 11 Oct 2014, 13:47
by nicktennear
I've just replaced the whole of the housing after cracking the original (long story). I used the budget housing from Brickwerks and their fitting kit and so far it's all good. One word of warning though, the bolts holding the housing to the head were the rustiest Allen bolts ever so I cut through the cracked housing to get a better vantage point then used the Irwin bolt removers that Covkid (should really be Saint Covkid the amount of times I thank him when doing jobs on the van) recommended in his Wiki post about removing the early housing. Knowing that it's all new and fitted is good but if you doubt the seals and not the actual housing then refit the seals, see what happens and then get the new housing if the van keeps doing wees. I know it involves paying postage but works out cheaper in the long run not buying every bit at once that you might not need. I call these bits my spares stash but really there my bits I could have done without but didn't think properly stash. It's a big stash.

It is worth using the new housing top bolts from the kit though even if you're not changing the housing because at some point your original bolts will be impossible to remove (or they are now) and at some point you will need to replace the thermostat, worth checking your thermostat while the top's off.

Re: Coolant leak from Thermostat housing

Posted: 12 Oct 2014, 08:17
by ghost123uk
The temp senders on the stat housing have a habit of leaking. It's the weird clip and O ring fixing method that is the weak spot.

Re: Coolant leak from Thermostat housing

Posted: 12 Oct 2014, 12:36
by CovKid
Saint Covkid. :oops:

Not a problem fella. If any of my tips/articles have saved anyone grief/hardship/breakdowns then I'm only too happy. However, over the years I've been promised probably hundreds of beers and never got one except from 1664. :D

I still get called in by some local garages when they're mashing their brains trying to fix a v-dub. Getting too creaky to roll around underneath now but I'll always have a go!

As a tribute, I've swapped my avatar for a week.... :rofl

Re: Coolant leak from Thermostat housing

Posted: 12 Oct 2014, 13:26
by California Dreamin
The plastic thermostat housings are mounted using two allen key bolts, these go through steel sleeve inserts in the housing that corrode and expand over time eventually leading to the plastic around the mounting bolts splitting open.
I did mine last year and replaced the sensor O rings at the same time.

Martin

Re: Coolant leak from Thermostat housing

Posted: 21 Nov 2014, 10:18
by madoc
Update

I bought a new housing and seal kit.
The allen bolts were unmovable and corroded enough to be pretty much rounded off.
I removed all the sensors and wiring and then chiselled the old housing away enough to get some heat on the engine block and some grips on the bolt shafts and they came out.

turns out both sensors were sealed with silicon (no rubber seals).

Anyone else about to attempt a similar job would be advised that before you obtain the bits, to check the allen key into the housing to engine block bolts first and if they are bad to think about a new housing.