Thermostat Replacement Advice

callahanoffroad · Post by **callahanoffroad** » 17 Nov 2018, 16:00

Okay friends I need to change the thermostat on my 850 non turbo as the car isn't really blowing too much hot air except when I'm sitting still or when the engine is revving. So I'm thinking the thermostat is stuck open.

Well it's only two bolts right? No prob. Super easy. Except not. I cannot get the bolts to turn and I'm afraid I'm going to strip the bolts out. Any advice? I do have a massive impact wrench that I'm tempted to use.

WhatAmIDoing · Post by **WhatAmIDoing** » 17 Nov 2018, 16:05

I've heard of using a dremel with a cutting wheel to cut slits into the bolt heads for removal with a large flat head screw driver.

I do not think these are common bolts to snap, usually just strip the heads, so I would try the impact. But first, soak everything in your favorite penetrating oil. Also, you are 100% going to want new, quality steel bolts.

Post by **cn90** » 17 Nov 2018, 16:27

Spray the bolts with PB Blaster etc.
Let it sit for a day then come back tomorrow.

callahanoffroad · Post by **callahanoffroad** » 17 Nov 2018, 16:44

WhatAmIDoing wrote: ↑17 Nov 2018, 16:05 I've heard of using a dremel with a cutting wheel to cut slits into the bolt heads for removal with a large flat head screw driver.

I do not think these are common bolts to snap, usually just strip the heads, so I would try the impact. But first, soak everything in your favorite penetrating oil. Also, you are 100% going to want new, quality steel bolts.

Any idea what size bolts they are?

Post by **scot850** » 17 Nov 2018, 16:45

+ 1 on what the guys have said. I also have an elongated 3/8" Torx socket which allows the shaft to sit square against the side of the head. When I soak it with penetrating oil I use the Torx socket and give it a few taps with a hammer to try to shock the aluminum and steel threads to give a gap for the penetrating oil to work down.

Let is sit for 24hrs and tap again before trying to remove. I have a long 3/8" breaker bar and with as much downward pressure as possible, give it sharp tugs to try to break it loose rather than a steady pressure. To date have not stripped a thread or break a thermostat housing. Problem as usual is modern manufacturers using dis-similar metals which react and 'weld' to each others.

Good luck!

Neil.

Post by **xHeart** » 17 Nov 2018, 18:23

T40 long.
For a clean job the fuel line can be undone.
The torx head will likely strip. You will need two new screws.

callahanoffroad · Post by **callahanoffroad** » 17 Nov 2018, 18:30

Good news fcp carries new ones ready to go.

Post by **wizechatmgr** » 17 Nov 2018, 18:41

Worst case scenario - I believe the whole housing can be removed from the engine. Obviously this too isn't fun...

callahanoffroad · Post by **callahanoffroad** » 17 Nov 2018, 18:44

wizechatmgr wrote: ↑17 Nov 2018, 18:41 Worst case scenario - I believe the whole housing can be removed from the engine. Obviously this too isn't fun...

That's the, I'm taking my ball and going home scenario.

Post by **wizechatmgr** » 17 Nov 2018, 18:47

callahanoffroad wrote: ↑17 Nov 2018, 18:44
wizechatmgr wrote: ↑17 Nov 2018, 18:41 Worst case scenario - I believe the whole housing can be removed from the engine. Obviously this too isn't fun...
That's the, I'm taking my ball and going home scenario.

All else fails, cover half of the front of the radiator with cardboard until you can get it off - any heat that is more than you have will be heat you appreciate.

I believe I shocked my bolts with a couple pound sledge on the end of a 3/8" extension before I removed them.