Thermostat woes

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gazzoouk
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Thermostat woes

Post by gazzoouk »

Hi,

my 1.8l was running fine apart from the temperature never lifted from the base line. So I decided to replace the thermostat as it was only £2.99 and shouldn't take longer than an hour to fit................how wrong I was.

I cleaned up the three bolt heads securing the thermostat housing and proceeded to slacken off the 1st bolt, snap, off came the head #*"$#. Oh well move on to the next one, same thing again, snapped bolt head. Oh well move on to the last one, yeah your getting the picture now.

I removed the housing. I am now faced with three broken bolts that need to be removed. Not being particularly mechanically gifted (I bet you guessed that already?) I scoured the internet on how these could be removed. I found that I needed to apply heat to the problem so off to B & Q to purchase a gas powered heat gun.

I stripped out all the plastic bits and pieces that would have been adversely affected by the heat and set about blasting the housing . The theory being that the aluminium housing will expand more than the steel bolt and so release it's grip. I blasted the first bolt for about 6 - 7 minutes then got a set of grips clamped them on the bolt and tried to unscrew it. The #@£ing thing didn't move a bit. I tried the same with the other two and got the same result.

I just don't know what to do. I looked into the possibility of removing the whole aluminium casting but the amount of work and possibility of things that could go wrong ruled this option out for me.

If anyone can anyone offer any advice (keep it clean. lol) I would appreciate it?

regards

Gary :cry
colin1
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Re: Thermostat woes

Post by colin1 »

What's the arrangement with the 1.8's thermostat - behind the timing case or out front from the block to the radiator?
93K C20XE Cavalier SRi Hatchback Spectral Blue Metallic
94M X20XEV Cavalier SRi Hatchback Flame Red

96N C14NZ Corsa B 4-dr Flame Red'ish
gazzoouk
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Re: Thermostat woes

Post by gazzoouk »

Hi Colin,

the bit with the bolts that are stuck sits between the block and timing belt etc. I have given a link to a photo I took yesterday;

Image

Gaz
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Cavalier342
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Re: Thermostat woes

Post by Cavalier342 »

They are a pain in the ass those thermostat housings, your easiest bet is to source a new housing from a donor engine, and swap it out, if you can find a good one without broken bolt studs in the holes.

I've had one snap on me, ended up running with 2 bolts holding it on for years with no problems, I swapped out the old bolts for new stainless steel allen bolts.

The other option you have is more fiddly and probably expensive/time consuming, is to drill out the stuck bolts, and re-bore/thread the holes. It's up to you really.
Previous:
China Blue 1989 Vauxhall Cavalier L 18SV
Kings Blue 1992 Vauxhall Cavalier LSi Auto C18NZ
Smoke Grey 1994 Vauxhall Cavalier V6 C25XE

Am I a light sleeper or a heavy sleeper? Well that depends on how much I've had to drink...
colin1
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Re: Thermostat woes

Post by colin1 »

They look awfully set in..
it's either oodles of patience with a good penetrator and cut some grooves in the tops of the stumps with a hacksaw and try and draw them out with a short blade screwdriver or cut your losses and replace the unit.
93K C20XE Cavalier SRi Hatchback Spectral Blue Metallic
94M X20XEV Cavalier SRi Hatchback Flame Red

96N C14NZ Corsa B 4-dr Flame Red'ish
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Cavalier342
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Re: Thermostat woes

Post by Cavalier342 »

Also that temperature sender unit has seen way better days, and that probably makes the temperature gauge needle stay in the blue more than the stat itself. I'd probably replace the unit as suggested, with the sender unit, they're less than a tenner and easy to replace, unbolt-bolt back in.
Previous:
China Blue 1989 Vauxhall Cavalier L 18SV
Kings Blue 1992 Vauxhall Cavalier LSi Auto C18NZ
Smoke Grey 1994 Vauxhall Cavalier V6 C25XE

Am I a light sleeper or a heavy sleeper? Well that depends on how much I've had to drink...
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Robsey
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Re: Thermostat woes

Post by Robsey »

Whatever you do - it is not worth buying a new casting.

Genuine parts search want £216 for one,
And Vauxhall World Parts want £209. !!!

Eeeek!!

Looks like a scrapper is your best option.
Or drilling out the bolts and cleaning up the bolt hole threads.

I personally would drill out the studs, but then I have done this a fair few times on old cars.

There also looks like plenty of stud length to saw a slot into for a screwdriver to have a go at undoing them.
gazzoouk
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Re: Thermostat woes

Post by gazzoouk »

Thank you to all that have taken time to respond. I think initially I will initially try with some extractors and if that fails I will attempt to drill the little buggers out. My thoughts being that if that fails I will have no choice then but to source a second hand casting. Swapping out the casting is a big job (for me) so I want to make it a last resort.

regards

Gaz :cheers
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Mikebmth
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Re: Thermostat woes

Post by Mikebmth »

Nasty ain't they, mine was the same even after heat and lots of Plus gas to try and loosen things up..

Unfortunately due to their location the easiest way is to swap out the entire unit that the Thermostat mates to, it does mean a timing belt change and waterpump with tensioner to do it properly and cost me in excess of £200 as used a local mechanic as didn't fancy setting the timing myself either.

Just another flawed Vauxhall design I'm afraid to say, don't think I'd want to do it twice but Vauxspares sorted me out a secondhand unit for about £20, readily available still.
Free Parking is a bonus, leaving my Cav in a carbon dust filled carpark is not.....
snowy
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Re: Thermostat woes

Post by snowy »

Take it to your local engineers or fabricators. They will get them out for you no problem.

Unless you're close to north wales. Getting these out isn't too bad once you have done a few.
gazzoouk
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Re: Thermostat woes

Post by gazzoouk »

Hello again,

A little update on my thermostat woes.

well i have just spent the last two hours in the cold first trying to extract the broken studs but in the end they wouldn't budge so i have managed to drill them out. I have managed to insert three Allen head bolts (i had to shave a bit off the heads to make them fit) through the rear of the holes to give me three studs to wind nuts onto.

Ha ha i thought jobs a good un...... Iv'e just looked at the thermostat housing and noticed one of the two "tangs" that retains the thermostat has broken so the thermostat doesn't sit correctly and i assume wont operate correctly either. I didn't notice this when i dissmantled it, it was only when i tried to fit the new thermostat.

Just so i can use the car i have re-assembled it without the thermostat fitted as i thought this would be the best temporary option.

Now for the life of me i don't know where i am going to get a second hand or even new replacment thermostat housing. :wall

I have seached Ebay etc but the only ones i can find are for the Cavaliers/Calibre's that are twin cam models.

Please can anyone point me in the direction of a replacement part and save my sanity??? :?

regards

Gaz
snowy
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Re: Thermostat woes

Post by snowy »

gazzoouk wrote:Hello again,

A little update on my thermostat woes.

well i have just spent the last two hours in the cold first trying to extract the broken studs but in the end they wouldn't budge so i have managed to drill them out. I have managed to insert three Allen head bolts (i had to shave a bit off the heads to make them fit) through the rear of the holes to give me three studs to wind nuts onto.

Ha ha i thought jobs a good un...... Iv'e just looked at the thermostat housing and noticed one of the two "tangs" that retains the thermostat has broken so the thermostat doesn't sit correctly and i assume wont operate correctly either. I didn't notice this when i dissmantled it, it was only when i tried to fit the new thermostat.

Just so i can use the car i have re-assembled it without the thermostat fitted as i thought this would be the best temporary option.

Now for the life of me i don't know where i am going to get a second hand or even new replacment thermostat housing. :wall

I have seached Ebay etc but the only ones i can find are for the Cavaliers/Calibre's that are twin cam models.

Please can anyone point me in the direction of a replacement part and save my sanity??? :?

regards

Gaz
I have a few off an 1800 engine. Can you post a pic of yours showing the sensors etc screwed into it to see if the ones I have are the same. I know the bodies are the same. Mine just might be missing a few holes.
gazzoouk
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Re: Thermostat woes

Post by gazzoouk »

Hi Snowy,

heres a link to a couple of pictures i have taken this morning;

http://i1038.photobucket.com/albums/a46 ... mbp3rg.jpg

http://i1038.photobucket.com/albums/a46 ... flktfy.jpg

i hope you can help. :wave

Gaz
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Robsey
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Re: Thermostat woes

Post by Robsey »

According to EPC4...

Part numbet 90 280 746.
Thermostat Housing and Water Outlet.

This should fit the following engines.
C16NZ2, X16SZ, 18SV, C18NZ, E18NVR, 20NE, C20NE, 20SEH...

So any of the big block 8 valve petrol engines.

It does say 14NV and 16SV E16NZ, C16NZ
So small-block heads too.

So only exclusions are 16 valve, V6 and diesel engines...

Image

Image
gazzoouk
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Re: Thermostat woes

Post by gazzoouk »

Hi Robsey,

thank you for the response. I only need to replace the part that holds the thermostat and then bolts to the part you have kindly shown. It's the part shown in the photo links i have posted in the above post and it doesn't have any sensers or anything coming out of it, just the large coolent hose from the radiator.

Gaz
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Robsey
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Re: Thermostat woes

Post by Robsey »

If it is the front housing itself, then these are readily available on the standard C18NZ engine as an integral part of the stat itself.

It is a bit more expensive but a lot easier to get hold of.

Vauxhall world parts are doing these for under £10..
90232012

Or this one is about £15...
90443473
gazzoouk
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Re: Thermostat woes

Post by gazzoouk »

Thanks Robsey,

that looks like just the thing i'm after. :thumb Thank you again. BTW how do you find the Vauxhall part numbers?

I will keep you posted.

regards

Gaz
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Robsey
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Re: Thermostat woes

Post by Robsey »

I use ecat24...
There are other sites available too.

Here is your part.
Part number 8 on here.

http://ecat24.com/opel/catalog/part/1/39/227/4211/9621/

You can get these from any auto-factors.
Or ebay is your friend if you can wait.

I usually put in "vauxhall" and the part number into google.
gazzoouk
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Re: Thermostat woes

Post by gazzoouk »

Robsey,

you are a star :cheers
thank you for help.

Gaz :D
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Robsey
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Re: Thermostat woes

Post by Robsey »

My pleasure...
It keeps the old grey cells active.
gazzoouk
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Re: Thermostat woes

Post by gazzoouk »

Quick update,

Saturday morning I tapped the holes in the main water jacket out to an M8 thread size. I did this carefully as there wasn't a lot of meat left on the main housing. I also had to open up the holes in the new thermostat housing that I had brought again being careful.
I refitted everything using copper grease on the bolts, fired up the engine to check for leaks then took it for a 5mile test run. All sorted :lol:

thanks again to all of you that took the time to respond, it is much appreciated. :thumb

Gaz
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Cavalier342
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Re: Thermostat woes

Post by Cavalier342 »

Well a solution to a problem is always the best thing, glad to hear it.
Previous:
China Blue 1989 Vauxhall Cavalier L 18SV
Kings Blue 1992 Vauxhall Cavalier LSi Auto C18NZ
Smoke Grey 1994 Vauxhall Cavalier V6 C25XE

Am I a light sleeper or a heavy sleeper? Well that depends on how much I've had to drink...
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Robsey
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Re: Thermostat woes

Post by Robsey »

Yayy...

I likes a happy endin'

Just need to be a bit more cautious in future when tightening the bolts up.

-----------------------------------------------------

As a point of future reference - I would have heli-coiled the stat casting.
It prevents thread stripping in future.
And being stainless wire inserts, they don't chemically weld together.
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Robsey
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Re: Thermostat woes

Post by Robsey »

Image

Image

Image
snowy
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Re: Thermostat woes

Post by snowy »

Sorry, only just seen this.
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