Thermostat which way round

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T25boy71
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Thermostat which way round

Post by T25boy71 »

Hello Hope you can help. I’ve change the thermostat on my van it’s a TD 
When I removed the thermostat it fell out So I’m not 100% sure of which way round it goes, any one know which way round it go’s let me know  
many thanks
Vw T25 1.9 TD Z1 hightop rusty but Less rusty than when I got it. lol: 😊

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ZsZ
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Re: Thermostat which way round

Post by ZsZ »

The longer side with the spring is up inside the water pump. The two frame tabs on the side of the thermostat are parallel to the belts.
Zoltan
1986 Multivan ex-Caravelle. Van since 2006, running mTDi 1Z since 2008 with Fiat Croma 1.9 TDid pump 2008-2019, custom pump since 2019
5spd custom box 4.57 diff + 0.74 5th

T25boy71
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Re: Thermostat which way round

Post by T25boy71 »

Ok I did put it in spring end into water pump so that bits ok the side tabs I don’t quite  know what you mean buy parallel to the belts  phots
my problem is the thermostat is not opening it is stone cold behind the closed thermostat I’ve driven 20 plus miles and it’s still stone cold behind the thermostat the rad gets a warm lower corner I bleed the rad no air just cold fluid.
I only changed the thermostat as a precaution as not much history came with it.ImageImage
Vw T25 1.9 TD Z1 hightop rusty but Less rusty than when I got it. lol: 😊

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ZsZ
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Re: Thermostat which way round

Post by ZsZ »

T25boy71 wrote: 25 Jan 2021, 14:35 Image
Looking from above you should see this side of the thermostat.
The side tabs can block the water going to the water pump impeller making it opening later but in theory it should not matter.

JX has a 87 C termostat with partnr 068 121 113 H 
Zoltan
1986 Multivan ex-Caravelle. Van since 2006, running mTDi 1Z since 2008 with Fiat Croma 1.9 TDid pump 2008-2019, custom pump since 2019
5spd custom box 4.57 diff + 0.74 5th

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Mr Bean
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Re: Thermostat which way round

Post by Mr Bean »

Just poking my nose in here:
Looking that part number up on tinternet I couldn't see a jiggle pin or bleed hole/notch. I have to wonder if this function is achieved by some other means on vehicles using this thermostat?
Anybody?
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boatbuilder
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Re: Thermostat which way round

Post by boatbuilder »

I didn't think they had a bleed hole. People sometimes drill a small hole in the thermostat itself but I think thats a botch job.

Here's an 87 degree one that was fitted in my 1.9dAEF

Image

And an old 87 degree one out of a 1.6dCS- this one was sticking due to the displaced rubber seal.

I'm running an 80 degree one now in my 1.9dAEF

Image
1984 1.9D (AEF Code) T25
My 84 Rusty Project

T25boy71
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Re: Thermostat which way round

Post by T25boy71 »

I’m confused I don’t see why the thermostat is not opening unless there’s air trapped inside the water pump where the thermostat sits “I did test thermostat before fitting” any thoughts
Vw T25 1.9 TD Z1 hightop rusty but Less rusty than when I got it. lol: 😊

boatbuilder
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Re: Thermostat which way round

Post by boatbuilder »

You could just have a faulty thermostat that tends to stick closed. The one I got was calorstat brand which I think is a good one.
You could try drilling a tiny hole say 2mm in the stat to eliminate air bubbles, but it shouldn't be necessary.
1984 1.9D (AEF Code) T25
My 84 Rusty Project

T25boy71
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Re: Thermostat which way round

Post by T25boy71 »

Ok I have 3 thermostat 1 old 2 new the old 1 and 1 of the new 1 I have tested and they work the only difference was the old 1 did not open quite as much as the new 1 dose the other new 1 is in the van the problem is both the new 1s don’t open when there in the waterpump, dose the orientation of the thermostat really matter? The thermostat that is in now does have a lower open temp of 82c not 87c/88c. That’s not opening either I will remove and test. Am I missing something?
Vw T25 1.9 TD Z1 hightop rusty but Less rusty than when I got it. lol: 😊

boatbuilder
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Re: Thermostat which way round

Post by boatbuilder »

Maybe your engine just isn't getting up to operating temperature - take her for a decent drive and then leave her sitting idling for a few minutes afterwards.
1984 1.9D (AEF Code) T25
My 84 Rusty Project

T25boy71
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Re: Thermostat which way round

Post by T25boy71 »

You may have something there the temp gauge Very rearly  gone over the first white block on the gauge,  I did change the On the expansion tank for a new one aftermarket from JK at the same time as I change the thermostat that be causing a problem?
i’ll change the cat back and give it a drive and see if that does anything I’ll keep you posted
Vw T25 1.9 TD Z1 hightop rusty but Less rusty than when I got it. lol: 😊

T25boy71
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Re: Thermostat which way round

Post by T25boy71 »

Ok I’ve removed the thermostat and tested it all ok starts to open at 82c and fully open at 90c. 
so I’m at a loss I can’t see why it’s not opening in the van maybe it’s air just needs bleeding.
any thoughts 
Vw T25 1.9 TD Z1 hightop rusty but Less rusty than when I got it. lol: 😊

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